Kouloulias, Vassilis; Karanasiou, Irene; Koutsoupidou, Maria; Matsopoulos, George; Kouvaris, John; Uzunoglu, Nikolaos
2015-01-01
Background. Deep heating is still the main subject for research in hyperthermia treatment. Aim. The purpose of this study was to develop and analyze a simple loop as a heating applicator. Methods. The performance of two 27 MHz inductive loop antennas as potential applicators in hyperthermia treatment was studied theoretically as well as experimentally in phantoms. Two inductive loop antennas with radii 7 cm and 9 cm were designed, simulated, and constructed. The theoretical analysis was performed by using Green's function and Bessel's function technique. Experiments were performed with phantoms radiated by the aforementioned loop antennas. Results. The specific absorption rate (SAR) distributions were estimated from the respective local phantom temperature measurements. Comparisons of the theoretical, simulation, and experimental studies showed satisfying agreement. The penetration depth was measured theoretically and experimentally in the range of 2–3.5 cm. Conclusion. The theoretical and experimental analysis showed that current loops are efficient in the case where the peripheral heating of spherical tumor formation located at 2–3.5 cm depth is required. PMID:26649070
A theoretical analysis of steady-state photocurrents in simple silicon diodes
NASA Technical Reports Server (NTRS)
Edmonds, L.
1995-01-01
A theoretical analysis solves for the steady-state photocurrents produced by a given photo-generation rate function with negligible recombination in simple silicon diodes, consisting of a uniformly doped quasi-neutral region (called 'substrate' below) adjacent to a p-n junction depletion region (DR). Special attention is given to conditions that produce 'funneling' (a term used by the single-eventeffects community) under steady-state conditions. Funneling occurs when carriers are generated so fast that the DR becomes flooded and partially or completely collapses. Some or nearly all of the applied voltage, plus built-in potential normally across the DR, is now across the substrate. This substrate voltage drop affects substrate currents. The steady-state problem can provide some qualitative insights into the more difficult transient problem. First, it was found that funneling can be induced from a distance, i.e., from carriers generated at locations outside of the DR. Secondly, it was found that the substrate can divide into two subregions, with one controlling substrate resistance and the other characterized by ambipolar diffusion. Finally, funneling was found to be more difficult to induce in the p(sup +)/n diode than in the n(sup +)/p diode. The carrier density exceeding the doping density in the substrate and at the DR boundary is not a sufficient condition to collapse a DR.
NASA Astrophysics Data System (ADS)
Wearing, M.; Hindmarsh, R. C. A.; Worster, G.
2014-12-01
Ice-shelf calving-rates and the buttressing ice shelves provide to grounded ice are both difficult to model and quantify. An increased understanding of the mechanics of this process is imperative in determining the dynamics of marine ice sheets and consequently predicting their future extent and thickness. Alley et al. (2008) proposed an empirically derived calving law, relating the calving rate to the strain rate at the calving front. However, Hindmarsh (2012) showed that a similar relationship could be deduced by considering the viscous flow of the ice shelf. We investigate the relationship between the ice shelf flow field and the strain rate field in the area close to the calving front. Analysis is undertaken of ice surface velocity data for a range of large Antarctic ice shelves (data from Rignot et al., 2011) and an inferred strain rate field produced from that data. These geophysical results are compared with a series of simple mathematical models from which thickness profiles and velocity fields can be obtained for a range of geometries and flow regimes. Fluid mechanical laboratory experiments simulating the flow of an ice shelf in an idealized channel geometry provide a further comparison to the theoretical models and geophysical data, and allow a wider range of parameters to be tested. We show some results from these laboratory experiments aimed at exploring the success of the mathematical models.
Simple theoretical models for composite rotor blades
NASA Technical Reports Server (NTRS)
Valisetty, R. R.; Rehfield, L. W.
1984-01-01
The development of theoretical rotor blade structural models for designs based upon composite construction is discussed. Care was exercised to include a member of nonclassical effects that previous experience indicated would be potentially important to account for. A model, representative of the size of a main rotor blade, is analyzed in order to assess the importance of various influences. The findings of this model study suggest that for the slenderness and closed cell construction considered, the refinements are of little importance and a classical type theory is adequate. The potential of elastic tailoring is dramatically demonstrated, so the generality of arbitrary ply layup in the cell wall is needed to exploit this opportunity.
Dimensional analysis made simple
NASA Astrophysics Data System (ADS)
Lira, Ignacio
2013-11-01
An inductive strategy is proposed for teaching dimensional analysis to second- or third-year students of physics, chemistry, or engineering. In this strategy, Buckingham's theorem is seen as a consequence and not as the starting point. In order to concentrate on the basics, the mathematics is kept as elementary as possible. Simple examples are suggested for classroom demonstrations of the power of the technique and others are put forward for homework or experimentation, but instructors are encouraged to produce examples of their own.
A Simple Plant Growth Analysis.
ERIC Educational Resources Information Center
Oxlade, E.
1985-01-01
Describes the analysis of dandelion peduncle growth based on peduncle length, epidermal cell dimensions, and fresh/dry mass. Methods are simple and require no special apparatus or materials. Suggests that limited practical work in this area may contribute to students' lack of knowledge on plant growth. (Author/DH)
Amano, Ken-ichi Takahashi, Ohgi; Suzuki, Kazuhiro; Fukuma, Takeshi; Onishi, Hiroshi
2013-12-14
The density of a liquid is not uniform when placed on a solid. The structured liquid pushes or pulls a probe employed in atomic force microscopy, as demonstrated in a number of experimental studies. In the present study, the relation between the force on a probe and the local density of a liquid is derived based on the statistical mechanics of simple liquids. When the probe is identical to a solvent molecule, the strength of the force is shown to be proportional to the vertical gradient of ln(ρ{sub DS}) with the local liquid's density on a solid surface being ρ{sub DS}. The intrinsic liquid's density on a solid is numerically calculated and compared with the density reconstructed from the force on a probe that is identical or not identical to the solvent molecule.
Theoretical Analysis of a Pulse Tube Regenerator
NASA Technical Reports Server (NTRS)
Roach, Pat R.; Kashani, Ali; Lee, J. M.; Cheng, Pearl L. (Technical Monitor)
1995-01-01
A theoretical analysis of the behavior of a typical pulse tube regenerator has been carried out. Assuming simple sinusoidal oscillations, the static and oscillatory pressures, velocities and temperatures have been determined for a model that includes a compressible gas and imperfect thermal contact between the gas and the regenerator matrix. For realistic material parameters, the analysis reveals that the pressure and, velocity oscillations are largely independent of details of the thermal contact between the gas and the solid matrix. Only the temperature oscillations depend on this contact. Suggestions for optimizing the design of a regenerator are given.
A theoretical model of sheath fold morphology in simple shear
NASA Astrophysics Data System (ADS)
Reber, Jacqueline E.; Dabrowski, Marcin; Galland, Olivier; Schmid, Daniel W.
2013-04-01
Sheath folds are highly non-cylindrical structures often associated with shear zones. The geometry of sheath folds, especially cross-sections perpendicular to the stretching direction that display eye-patterns, have been used in the field to deduce kinematic information such as shear sense and bulk strain type. However, how sheath folds form and how they evolve with increasing strain is still a matter of debate. We investigate the formation of sheath folds around a weak inclusion acting as a slip surface in simple shear by means of an analytical model. We systematically vary the slip surface orientation and shape and evaluate the impact on the evolving eye-pattern. In addition we compare our results to existing classifications. Based on field observations it has been suggested that the shear sense of a shear zone can be determined by knowing the position of the center of an eye-pattern and the closing direction of the corresponding sheath fold. In our modeled sheath folds we can observe for a given strain that the center of the eye-structure is subject to change in height with respect to the upper edge of the outermost closed contour for different cross-sections perpendicular to the shear direction. This results in a large variability in layer thickness, questioning the usefulness of sheath folds as shear sense indicators. The location of the center of the eye structure, however, is largely invariant to the initial configurations of the slip surface as well as to strain. It has been suggested that the ratio of the aspect ratio of the innermost and outermost closed contour in eye-patterns could be linked to the bulk strain type based on filed observations. We apply this classification to our modeled sheath folds and we observe that the values of the aspect ratios of the closed contours within the eye-pattern are dependent on the strain and the cross-section location. The ratio (R') of the aspect ratios of the outermost closed contour (Ryz) and the innermost closed
Simple Numerical Analysis of Longboard Speedometer Data
ERIC Educational Resources Information Center
Hare, Jonathan
2013-01-01
Simple numerical data analysis is described, using a standard spreadsheet program, to determine distance, velocity (speed) and acceleration from voltage data generated by a skateboard/longboard speedometer (Hare 2012 "Phys. Educ." 47 409-17). This simple analysis is an introduction to data processing including scaling data as well as…
Theoretical analysis of ARC constriction
Stoenescu, M.L.; Brooks, A.W.; Smith, T.M.
1980-12-01
The physics of the thermionic converter is governed by strong electrode-plasma interactions (emissions surface scattering, charge exchange) and weak interactions (diffusion, radiation) at the maximum interelectrode plasma radius. The physical processes are thus mostly convective in thin sheaths in front of the electrodes and mostly diffusive and radiative in the plasma bulk. The physical boundaries are open boundaries to particle transfer (electrons emitted or absorbed by the electrodes, all particles diffusing through some maximum plasma radius) and to convective, conductive and radiative heat transfer. In a first approximation the thermionic converter may be described by a one-dimensional classical transport theory. The two-dimensional effects may be significant as a result of the sheath sensitivity to radial plasma variations and of the strong sheath-plasma coupling. The current-voltage characteristic of the converter is thus the result of an integrated current density over the collector area for which the boundary conditions at each r determine the regime (ignited/unignited) of the local current density. A current redistribution strongly weighted at small radii (arc constriction) limits the converter performance and opens questions on constriction reduction possibilities. The questions addressed are the followng: (1) what are the main contributors to the loss of current at high voltage in the thermionic converter; and (2) is arc constriction observable theoretically and what are the conditions of its occurrence. The resulting theoretical problem is formulated and results are given. The converter electrical current is estimated directly from the electron and ion particle fluxes based on the spatial distribution of the electron/ion density n, temperatures T/sub e/, T/sub i/, electrical voltage V and on the knowledge of the transport coefficients. (WHK)
Simple control-theoretic models of human steering activity in visually guided vehicle control
NASA Technical Reports Server (NTRS)
Hess, Ronald A.
1991-01-01
A simple control theoretic model of human steering or control activity in the lateral-directional control of vehicles such as automobiles and rotorcraft is discussed. The term 'control theoretic' is used to emphasize the fact that the model is derived from a consideration of well-known control system design principles as opposed to psychological theories regarding egomotion, etc. The model is employed to emphasize the 'closed-loop' nature of tasks involving the visually guided control of vehicles upon, or in close proximity to, the earth and to hypothesize how changes in vehicle dynamics can significantly alter the nature of the visual cues which a human might use in such tasks.
A simple theoretical model for ⁶³Ni betavoltaic battery.
Zuo, Guoping; Zhou, Jianliang; Ke, Guotu
2013-12-01
A numerical simulation of the energy deposition distribution in semiconductors is performed for ⁶³Ni beta particles. Results show that the energy deposition distribution exhibits an approximate exponential decay law. A simple theoretical model is developed for ⁶³Ni betavoltaic battery based on the distribution characteristics. The correctness of the model is validated by two literature experiments. Results show that the theoretical short-circuit current agrees well with the experimental results, and the open-circuit voltage deviates from the experimental results in terms of the influence of the PN junction defects and the simplification of the source. The theoretical model can be applied to ⁶³Ni and ¹⁴⁷Pm betavoltaic batteries. PMID:23974307
Diaz, Carlos; Llovera, Ligia; Echevarria, Lorenzo; Hernández, Florencio E
2015-02-01
Herein, we present a simple and versatile theoretical-experimental approach to assess the tautomeric distribution on 5(6)-aminobenzimidazole (5(6)-ABZ) derivatives in solution via one-photon absorption. The method is based on the optimized weighted sum of the theoretical spectra of the corresponding tautomers. In this article we show how the choice of exchange-correlation functional (XCF) employed in the calculations becomes crucial for the success of the approach. After the systematic analysis of XCFs with different amounts of exact-exchange we found a better performance for B3LYP and PBE0. The direct test of the proposed method on omeprazole, a well-known 5(6)-benzimidazole based pharmacotherapeutic, demonstrate its broader applicability. The proposed approach is expected to find direct applications on the tautomeric analysis of other molecular systems exhibiting similar tautomeric equilibria. PMID:25510544
NEMP Qualification of Electrically Simple Equipment on Aircraft via Analysis
NASA Astrophysics Data System (ADS)
Ockerse, J.; Flessa, C.
2012-05-01
The purpose of this paper is to demonstrate a theoretical analysis method for analysing the NEMP (Nuclear Electromagnetic Pulse) qualification status of electrically simple equipment or devices. (e.g., switches, actuators, sensors, etc.) The method is transparent to the certification authorities. This is in order to release them from the (costly) requirement for actual NEMP testing of these parts. This work is based on the experience gained in the successful certification of an advanced, all-carbon- fibre-composite (CFC) military helicopter. The method has been validated by testing.
Simple gas chromatographic method for furfural analysis.
Gaspar, Elvira M S M; Lopes, João F
2009-04-01
A new, simple, gas chromatographic method was developed for the direct analysis of 5-hydroxymethylfurfural (5-HMF), 2-furfural (2-F) and 5-methylfurfural (5-MF) in liquid and water soluble foods, using direct immersion SPME coupled to GC-FID and/or GC-TOF-MS. The fiber (DVB/CAR/PDMS) conditions were optimized: pH effect, temperature, adsorption and desorption times. The method is simple and accurate (RSD<8%), showed good recoveries (77-107%) and good limits of detection (GC-FID: 1.37 microgL(-1) for 2-F, 8.96 microgL(-1) for 5-MF, 6.52 microgL(-1) for 5-HMF; GC-TOF-MS: 0.3, 1.2 and 0.9 ngmL(-1) for 2-F, 5-MF and 5-HMF, respectively). It was applied to different commercial food matrices: honey, white, demerara, brown and yellow table sugars, and white and red balsamic vinegars. This one-step, sensitive and direct method for the analysis of furfurals will contribute to characterise and quantify their presence in the human diet. PMID:18976770
Wenk, H.-R.; Takeshita, T.; Bechler, E.; Erskine, B.G.; Matthies, S.
1987-01-01
The pattern of lattice preferred orientation (texture) in deformed rocks is an expression of the strain path and the acting deformation mechanisms. A first indication about the strain path is given by the symmetry of pole figures: coaxial deformation produces orthorhombic pole figures, while non-coaxial deformation yields monoclinic or triclinic pole figures. More quantitative information about the strain history can be obtained by comparing natural textures with experimental ones and with theoretical models. For this comparison, a representation in the sensitive three-dimensional orientation distribution space is extremely important and efforts are made to explain this concept. We have been investigating differences between pure shear and simple shear deformation incarbonate rocks and have found considerable agreement between textures produced in plane strain experiments and predictions based on the Taylor model. We were able to simulate the observed changes with strain history (coaxial vs non-coaxial) and the profound texture transition which occurs with increasing temperature. Two natural calcite textures were then selected which we interpreted by comparing them with the experimental and theoretical results. A marble from the Santa Rosa mylonite zone in southern California displays orthorhombic pole figures with patterns consistent with low temperature deformation in pure shear. A limestone from the Tanque Verde detachment fault in Arizona has a monoclinic fabric from which we can interpret that 60% of the deformation occurred by simple shear. ?? 1987.
Theoretical analysis of multispectral image segmentation criteria.
Kerfoot, I B; Bresler, Y
1999-01-01
Markov random field (MRF) image segmentation algorithms have been extensively studied, and have gained wide acceptance. However, almost all of the work on them has been experimental. This provides a good understanding of the performance of existing algorithms, but not a unified explanation of the significance of each component. To address this issue, we present a theoretical analysis of several MRF image segmentation criteria. Standard methods of signal detection and estimation are used in the theoretical analysis, which quantitatively predicts the performance at realistic noise levels. The analysis is decoupled into the problems of false alarm rate, parameter selection (Neyman-Pearson and receiver operating characteristics), detection threshold, expected a priori boundary roughness, and supervision. Only the performance inherent to a criterion, with perfect global optimization, is considered. The analysis indicates that boundary and region penalties are very useful, while distinct-mean penalties are of questionable merit. Region penalties are far more important for multispectral segmentation than for greyscale. This observation also holds for Gauss-Markov random fields, and for many separable within-class PDFs. To validate the analysis, we present optimization algorithms for several criteria. Theoretical and experimental results agree fairly well. PMID:18267494
Diurnal and subdiurnal terms of nutation: a simple theoretical model for a nonrigid Earth.
NASA Astrophysics Data System (ADS)
Brzeziński, A.
This paper presents a simple theoretical description of the high frequency nutation. First we derive the equation describing the lunisolar excitation of polar motion. The underlying model of the Earth consists of the rotationally symmetrical elastic mantle and the liquid core, with no coupling between these two. Then, we give a systematic review of various components of the equatorial lunisolar torque and of the corresponding perturbation in Earth rotation. Our purpose is to find explicit analytical expressions involving both the parameters of geopotential and the tidal parameters, which gives us insight into the physical mechanism generating this minor, but not negligible, component of the lunisolar perturbation in Earth rotation and makes clear its geometry.
Simple Analysis of Historical Lime Mortars
ERIC Educational Resources Information Center
Pires, Joa~o
2015-01-01
A laboratory experiment is described in which a simple characterization of a historical lime mortar is made by the determination of its approximate composition by a gravimetric method. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) are also used for the qualitative characterization of the lime mortar components. These…
Simple yet Hidden Counterexamples in Undergraduate Real Analysis
ERIC Educational Resources Information Center
Shipman, Barbara A.; Shipman, Patrick D.
2013-01-01
We study situations in introductory analysis in which students affirmed false statements as true, despite simple counterexamples that they easily recognized afterwards. The study draws attention to how simple counterexamples can become hidden in plain sight, even in an active learning atmosphere where students proposed simple (as well as more…
Analysis of a theoretically optimized transonic airfoil
NASA Technical Reports Server (NTRS)
Lores, M. E.; Burdges, K. P.; Shrewsbury, G. D.
1978-01-01
Numerical optimization was used in conjunction with an inviscid, full potential equation, transonic flow analysis computer code to design an upper surface contour for a conventional airfoil to improve its supercritical performance. The modified airfoil was tested in a compressible flow wind tunnel. The modified airfoil's performance was evaluated by comparison with test data for the baseline airfoil and for an airfoil developed by optimization of leading edge of the baseline airfoil. While the leading edge modification performed as expected, the upper surface re-design did not produce all of the expected performance improvements. Theoretical solutions computed using a full potential, transonic airfoil code corrected for viscosity were compared to experimental data for the baseline airfoil and the upper surface modification. These correlations showed that the theory predicted the aerodynamics of the baseline airfoil fairly well, but failed to accurately compute drag characteristics for the upper surface modification.
Simple Sensitivity Analysis for Orion GNC
NASA Technical Reports Server (NTRS)
Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar
2013-01-01
The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch.We describe in this paper a sensitivity analysis tool (Critical Factors Tool or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.
Simple Low Level Features for Image Analysis
NASA Astrophysics Data System (ADS)
Falcoz, Paolo
As human beings, we perceive the world around us mainly through our eyes, and give what we see the status of “reality”; as such we historically tried to create ways of recording this reality so we could augment or extend our memory. From early attempts in photography like the image produced in 1826 by the French inventor Nicéphore Niépce (Figure 2.1) to the latest high definition camcorders, the number of recorded pieces of reality increased exponentially, posing the problem of managing all that information. Most of the raw video material produced today has lost its memory augmentation function, as it will hardly ever be viewed by any human; pervasive CCTVs are an example. They generate an enormous amount of data each day, but there is not enough “human processing power” to view them. Therefore the need for effective automatic image analysis tools is great, and a lot effort has been put in it, both from the academia and the industry. In this chapter, a review of some of the most important image analysis tools are presented.
Theoretical analysis of sheet metal formability
NASA Astrophysics Data System (ADS)
Zhu, Xinhai
Sheet metal forming processes are among the most important metal-working operations. These processes account for a sizable proportion of manufactured goods made in industrialized countries each year. Furthermore, to reduce the cost and increase the performance of manufactured products, in addition to the environmental concern, more and more light weight and high strength materials have been used as a substitute to the conventional steel. These materials usually have limited formability, thus, a thorough understanding of the deformation processes and the factors limiting the forming of sound parts is important, not only from a scientific or engineering viewpoint, but also from an economic point of view. An extensive review of previous studies pertaining to theoretical analyses of Forming Limit Diagrams (FLDs) is contained in Chapter I. A numerical model to analyze the neck evolution process is outlined in Chapter II. With the use of strain gradient theory, the effect of initial defect profile on the necking process is analyzed. In the third chapter, the method proposed by Storen and Rice is adopted to analyze the initiation of localized neck and predict the corresponding FLDs. In view of the fact that the width of the localized neck is narrow, the deformation inside the neck region is constrained by the material in the neighboring homogeneous region. The relative rotation effect may then be assumed to be small and is thus neglected. In Chapter IV, Hill's 1948 yield criterion and strain gradient theory are employed to obtain FLDs, for planar anisotropic sheet materials by using bifurcation analysis. The effects of the strain gradient coefficient c and the material anisotropic parameters R's on the orientation of the neck and FLDs are analyzed in a systematic manner and compared with experiments. In Chapter V, Hill's 79 non-quadratic yield criterion with a deformation theory of plasticity is used along with bifurcation analyses to derive a general analytical
Physical Violence between Siblings: A Theoretical and Empirical Analysis
ERIC Educational Resources Information Center
Hoffman, Kristi L.; Kiecolt, K. Jill; Edwards, John N.
2005-01-01
This study develops and tests a theoretical model to explain sibling violence based on the feminist, conflict, and social learning theoretical perspectives and research in psychology and sociology. A multivariate analysis of data from 651 young adults generally supports hypotheses from all three theoretical perspectives. Males with brothers have…
Interaction of Simple Ions with Water: Theoretical Models for the Study of Ion Hydration
ERIC Educational Resources Information Center
Gancheff, Jorge S.; Kremer, Carlos; Ventura, Oscar N.
2009-01-01
A computational experiment aimed to create and systematically analyze models of simple cation hydrates is presented. The changes in the structure (bond distances and angles) and the electronic density distribution of the solvent and the thermodynamic parameters of the hydration process are calculated and compared with the experimental data. The…
Rossi, Federico; Nicolini, Andrea
2003-05-01
No suitable handy tool is available to predict train-induced vibration on environmental impact assessment. A simple prediction model is proposed which has been calibrated for high speed trains. The model input data are train characteristics, train speed and track properties; model output data are soil time-averaged velocity and velocity level. Model results have been compared with numerous vibration data retrieved from measurement campaigns led along the most important high-speed European rail tracks. Model performances have been tested by comparing measured and predicted vibration values.
Theoretical analysis of the EWEC report
NASA Technical Reports Server (NTRS)
1976-01-01
This analytic investigation shows how the electromagnetic wave energy conversion (EWEC) device, as used for solar-to-electric power conversion, is significantly different from solar cells, with respect to principles of operation. An optimistic estimate of efficiency is about 80% for a full-wave rectifying configuration with solar radiation normally incident. This compares favorably with the theoretical maximum for a CdTe solar cell (23.5%), as well as with the efficiencies of more familiar cells: Si (19.5%), InP (21.5%), and GaAs (23%). Some key technological issues that must be resolved before the EWEC device can be realized are identified. Those issues include: the fabrication of a pn semi-conductor junction with no permittivity resonances in the optical band; and the efficient channeling of the power received by countless microscopic horn antennas through a relatively few number of wires.
Theoretical and experimental evidence of Fano-like resonances in simple monomode photonic circuits
NASA Astrophysics Data System (ADS)
Mouadili, A.; El Boudouti, E. H.; Soltani, A.; Talbi, A.; Akjouj, A.; Djafari-Rouhani, B.
2013-04-01
A simple photonic device consisting of two dangling side resonators grafted at two sites on a waveguide is designed in order to obtain sharp resonant states inside the transmission gaps without introducing any defects in the structure. This results from an internal resonance of the structure when such a resonance is situated in the vicinity of a zero of transmission or placed between two zeros of transmission, the so-called Fano resonances. A general analytical expression for the transmission coefficient is given for various systems of this kind. The amplitude of the transmission is obtained following the Fano form. The full width at half maximum of the resonances as well as the asymmetric Fano parameter are discussed explicitly as function of the geometrical parameters of the system. In addition to the usual asymmetric Fano resonance, we show that this system may exhibit an electromagnetic induced transparency resonance as well as well as a particular case where such resonances collapse in the transmission coefficient. Also, we give a comparison between the phase of the determinant of the scattering matrix, the so-called Friedel phase, and the phase of the transmission amplitude. The analytical results are obtained by means of the Green's function method, whereas the experiments are carried out using coaxial cables in the radio-frequency regime. These results should have important consequences for designing integrated devices such as narrow-frequency optical or microwave filters and high-speed switches. This system is proposed as a simpler alternative to coupled-micoresonators.
A theoretical analysis of basin-scale groundwater temperature distribution
NASA Astrophysics Data System (ADS)
An, Ran; Jiang, Xiao-Wei; Wang, Jun-Zhi; Wan, Li; Wang, Xu-Sheng; Li, Hailong
2015-03-01
The theory of regional groundwater flow is critical for explaining heat transport by moving groundwater in basins. Domenico and Palciauskas's (1973) pioneering study on convective heat transport in a simple basin assumed that convection has a small influence on redistributing groundwater temperature. Moreover, there has been no research focused on the temperature distribution around stagnation zones among flow systems. In this paper, the temperature distribution in the simple basin is reexamined and that in a complex basin with nested flow systems is explored. In both basins, compared to the temperature distribution due to conduction, convection leads to a lower temperature in most parts of the basin except for a small part near the discharge area. There is a high-temperature anomaly around the basin-bottom stagnation point where two flow systems converge due to a low degree of convection and a long travel distance, but there is no anomaly around the basin-bottom stagnation point where two flow systems diverge. In the complex basin, there are also high-temperature anomalies around internal stagnation points. Temperature around internal stagnation points could be very high when they are close to the basin bottom, for example, due to the small permeability anisotropy ratio. The temperature distribution revealed in this study could be valuable when using heat as a tracer to identify the pattern of groundwater flow in large-scale basins. Domenico PA, Palciauskas VV (1973) Theoretical analysis of forced convective heat transfer in regional groundwater flow. Geological Society of America Bulletin 84:3803-3814
Category Theoretic Analysis of Hierarchical Protein Materials and Social Networks
Spivak, David I.; Giesa, Tristan; Wood, Elizabeth; Buehler, Markus J.
2011-01-01
Materials in biology span all the scales from Angstroms to meters and typically consist of complex hierarchical assemblies of simple building blocks. Here we describe an application of category theory to describe structural and resulting functional properties of biological protein materials by developing so-called ologs. An olog is like a “concept web” or “semantic network” except that it follows a rigorous mathematical formulation based on category theory. This key difference ensures that an olog is unambiguous, highly adaptable to evolution and change, and suitable for sharing concepts with other olog. We consider simple cases of beta-helical and amyloid-like protein filaments subjected to axial extension and develop an olog representation of their structural and resulting mechanical properties. We also construct a representation of a social network in which people send text-messages to their nearest neighbors and act as a team to perform a task. We show that the olog for the protein and the olog for the social network feature identical category-theoretic representations, and we proceed to precisely explicate the analogy or isomorphism between them. The examples presented here demonstrate that the intrinsic nature of a complex system, which in particular includes a precise relationship between structure and function at different hierarchical levels, can be effectively represented by an olog. This, in turn, allows for comparative studies between disparate materials or fields of application, and results in novel approaches to derive functionality in the design of de novo hierarchical systems. We discuss opportunities and challenges associated with the description of complex biological materials by using ologs as a powerful tool for analysis and design in the context of materiomics, and we present the potential impact of this approach for engineering, life sciences, and medicine. PMID:21931622
Theoretical analysis of HVAC duct hanger systems
NASA Technical Reports Server (NTRS)
Miller, R. D.
1987-01-01
Several methods are presented which, together, may be used in the analysis of duct hanger systems over a wide range of frequencies. The finite element method (FEM) and component mode synthesis (CMS) method are used for low- to mid-frequency range computations and have been shown to yield reasonably close results. The statistical energy analysis (SEA) method yields predictions which agree with the CMS results for the 800 to 1000 Hz range provided that a sufficient number of modes participate. The CMS approach has been shown to yield valuable insight into the mid-frequency range of the analysis. It has been demonstrated that it is possible to conduct an analysis of a duct/hanger system in a cost-effective way for a wide frequency range, using several methods which overlap for several frequency bands.
Landscape analysis: Theoretical considerations and practical needs
Godfrey, A.E.; Cleaves, E.T.
1991-01-01
Numerous systems of land classification have been proposed. Most have led directly to or have been driven by an author's philosophy of earth-forming processes. However, the practical need of classifying land for planning and management purposes requires that a system lead to predictions of the results of management activities. We propose a landscape classification system composed of 11 units, from realm (a continental mass) to feature (a splash impression). The classification concerns physical aspects rather than economic or social factors; and aims to merge land inventory with dynamic processes. Landscape units are organized using a hierarchical system so that information may be assembled and communicated at different levels of scale and abstraction. Our classification uses a geomorphic systems approach that emphasizes the geologic-geomorphic attributes of the units. Realm, major division, province, and section are formulated by subdividing large units into smaller ones. For the larger units we have followed Fenneman's delineations, which are well established in the North American literature. Areas and districts are aggregated into regions and regions into sections. Units smaller than areas have, in practice, been subdivided into zones and smaller units if required. We developed the theoretical framework embodied in this classification from practical applications aimed at land use planning and land management in Maryland (eastern Piedmont Province near Baltimore) and Utah (eastern Uinta Mountains). ?? 1991 Springer-Verlag New York Inc.
A theoretical analysis of vertical flow equilibrium
Yortsos, Y.C.
1992-01-01
The assumption of Vertical Flow Equilibrium (VFE) and of parallel flow conditions, in general, is often applied to the modeling of flow and displacement in natural porous media. However, the methodology for the development of the various models is rather intuitive, and no rigorous method is currently available. In this paper, we develop an asymptotic theory using as parameter the variable R{sub L} = (L/H){radical}(k{sub V})/(k{sub H}). It is rigorously shown that present models represent the leading order term of an asymptotic expansion with respect to 1/R{sub L}{sup 2}. Although this was numerically suspected, it is the first time that is is theoretically proved. Based on the general formulation, a series of models are subsequently obtained. In the absence of strong gravity effects, they generalize previous works by Zapata and Lake (1981), Yokoyama and Lake (1981) and Lake and Hirasaki (1981), on immiscible and miscible displacements. In the limit of gravity-segregated flow, we prove conditions for the fluids to be segregated and derive the Dupuit and Dietz (1953) approximations. Finally, we also discuss effects of capillarity and transverse dispersion.
Theoretical and experimental analysis of mylar balloons
NASA Astrophysics Data System (ADS)
Romaguera, Antonio; Démery, Vincent; Davidovitch, Benny
2015-03-01
In the present study, we present a theoretical and experimental study of the problem known as the mylar balloon shape. The problem consists of inflating a balloon made of two circular discs of an unstretchable material sewed at the edge. A solution for this problem was given by W. H. Paulsen in 1994 for constrain free. In our analyzes, we fixed the height of the balloon and measure the inflated diameter. As a result, we were able to map the constrained shape in terms of the original mylar balloon's shape. The basic assumption of this problem is that the gravitational, stretching and bending energies are negligible compared with the mechanical energy - pV . Controlling the pressure and the height of the balloon, we are able to find the condition where these assumptions fail, specially in the limit h --> 0 for fixed p. A remarkable feature of this problem is the presence of wrinkles across the equator of the balloon. A precise description for that region must include the large deformation from the flat disc initial condition. We will also present some experimental data on the wrinkle's length and its connection with the pressure and height of the balloon.
Landscape analysis: Theoretical considerations and practical needs
NASA Astrophysics Data System (ADS)
Godfrey, Andrew E.; Cleaves, Emery T.
1991-03-01
Numerous systems of land classification have been proposed. Most have led directly to or have been driven by an author's philosophy of earth-forming processes. However, the practical need of classifying land for planning and management purposes requires that a system lead to predictions of the results of management activities. We propose a landscape classification system composed of 11 units, from realm (a continental mass) to feature (a splash impression). The classification concerns physical aspects rather than economic or social factors; and aims to merge land inventory with dynamic processes. Landscape units are organized using a hierarchical system so that information may be assembled and communicated at different levels of scale and abstraction. Our classification uses a geomorphic systems approach that emphasizes the geologic-geomorphic attributes of the units. Realm, major division, province, and section are formulated by subdividing large units into smaller ones. For the larger units we have followed Fenneman's delineations, which are well established in the North American literature. Areas and districts are aggregated into regions and regions into sections. Units smaller than areas have, in practice, been subdivided into zones and smaller units if required. We developed the theoretical framework embodied in this classification from practical applications aimed at land use planning and land management in Maryland (eastern Piedmont Province near Baltimore) and Utah (eastern Uinta Mountains).
Theoretical and experimental analysis of the physics of water rockets
NASA Astrophysics Data System (ADS)
Barrio-Perotti, R.; Blanco-Marigorta, E.; Fernández-Francos, J.; Galdo-Vega, M.
2010-09-01
A simple rocket can be made using a plastic bottle filled with a volume of water and pressurized air. When opened, the air pressure pushes the water out of the bottle. This causes an increase in the bottle momentum so that it can be propelled to fairly long distances or heights. Water rockets are widely used as an educational activity, and several mathematical models have been proposed to investigate and predict their physics. However, the real equations that describe the physics of the rockets are so complicated that certain assumptions are usually made to obtain models that are easier to use. These models provide relatively good predictions but fail in describing the complex physics of the flow. This paper presents a detailed theoretical analysis of the physics of water rockets that concludes with the proposal of a physical model. The validity of the model is checked by a series of field tests. The tests showed maximum differences with predictions of about 6%. The proposed model is finally used to investigate the temporal evolution of some significant variables during the propulsion and flight of the rocket. The experience and procedure described in this paper can be proposed to graduate students and also at undergraduate level if certain simplifications are assumed in the general equations.
Theoretical and Numerical Assessment of Strain Pattern Analysis
NASA Astrophysics Data System (ADS)
Milne, R. D.; Simpson, A.
1996-04-01
The Strain Pattern Analysis (SPA) method was conceived at the RAE in the 1970s as a means of estimating the displacement shape of a helicopter rotor blade by using only strain gauge data, but no attempt was made to provide theoretical justification for the procedure. In this paper, the SPA method is placed on a firm mathematical basis by the use of vector space theory. It is shown that the natural normwhich underlies the SPA projection is the strain energy functionalof the structure under consideration. The natural norm is a weightedversion of the original SPA norm. Numerical experiments on simple flexure and coupled flexure-torsion systems indicate that the use of the natural norm yields structural deflection estimates of significantly greater accuracy than those obtained from the original SPA procedure and that measurement error tolerance is also enhanced. Extensive numerical results are presented for an emulation of the SPA method as applied to existing mathematical models of the main rotor of the DRA Lynx ZD559 helicopter. The efficacy of SPA is demonstrated by using a quasi-linear rotor model in the frequency domain and a fully non-linear, kinematically exact model in the time domain: the procedure based on the natural (or weighted) norm is again found to be superior to that based on the original SPA method, both in respect of displacement estimates and measurement error tolerance.
Air Ingress Analysis: Part 1 - Theoretical Approach
Chang Ho Oh
2011-01-01
Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy (DOE), is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature gas-cooled reactors (VHTRs). Phenomena identification and ranking studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air-ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the VHTR through the break, possibly causing oxidation of the graphite core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of lower plenum graphite caused by graphite oxidation can lead to a loss of mechanical strength. Excessive oxidation of core graphite can also lead to a release of fission products into the confinement, which could be detrimental to reactor safety. Analytical models developed in this study will improve our understanding of this phenomenon. This paper presents two sets of analytical models for the qualitative assessment of the air ingress phenomena. The results from the analytical models are compared with results of the computational fluid dynamic models (CFD) in the subsequent paper. The analytical models agree well with those CFD results.
Simple Analysis of Prolate-Spin Attitude Stability
NASA Astrophysics Data System (ADS)
Kawase, Sei-Ichiro
How can a prolate satellite spinning about its axis of minimum moment of inertia be attitude-stabilized using dual spin? To this question, we find a simple, clear answer. We replace the satellite with an equivalent frame model and describe its attitude motion as small deviations from its nominal attitude. We show that a friction-like torque applied to the spin axis reduces its nutation motion, and that a similar torque is generated by a nutation damper on a de-spun platform. Thus, we derive a simple attitude-stability theory using minimal mathematical analysis. This theory is applicable to the spin stabilization of geosynchronous communication satellite.
Empirical and theoretical analysis of complex systems
NASA Astrophysics Data System (ADS)
Zhao, Guannan
structures evolve on a similar timescale to individual level transmission, we investigated the process of transmission through a model population comprising of social groups which follow simple dynamical rules for growth and break-up, and the profiles produced bear a striking resemblance to empirical data obtained from social, financial and biological systems. Finally, for better implementation of a widely accepted power law test algorithm, we have developed a fast testing procedure using parallel computation.
Medial Cochlear Efferent Function: A Theoretical Analysis
NASA Astrophysics Data System (ADS)
Mountain, David C.
2011-11-01
Since the discovery of the cochlear efferent system, many hypotheses have been put forth for its function. These hypotheses for its function range from protecting the cochlea from over stimulation to improving the detection of sounds in noise. It is known that the medial efferent system innervates the outer hair cells and that stimulation of this system reduces basilar membrane and auditory nerve sensitivity which suggests that this system acts to decrease the gain of the cochlear amplifier. Here I present modeling results as well as analysis of published experimental data that suggest that the function of the medial efferent reflex is to decrease the cochlear amplifier gain by just the right amount so that the nonlinearity in the basilar membrane response lines up perfectly with the inner hair cell nonlinear transduction process to produce a hair cell receptor potential that is proportional to the logarithm of the sound pressure level.
Graph theoretical analysis of climate data
NASA Astrophysics Data System (ADS)
Zerenner, T.; Hense, A.
2012-04-01
Applying methods from graph and network theory to climatological data is a quite new approach and contains numerous difficulties. The atmosphere is a high dimensional and complex dynamical system which per se does not show a network-like structure. It does not consist of well-defined nodes and edges. Thus considering such a system as a network or graph inevitably involves radical simplifications and ambiguities. Nevertheless network analysis has provided useful results for different kinds of complex systems for example in biology or medical science (neural and gene interaction networks). The application of these methods on climate data provides interesting results as well. If the network construction is based on the correlation matrix of the underlying data, the resulting network structures show many well known patterns and characteristics of the atmospheric circulation (Tsonis et al. 2006, Donges et al. 2009). The interpretation of these network structures is yet questionable. Using Pearson Correlation for network construction does not allow to differ between direct and indirect dependencies. An edge does not necessarily represent a causal connection. An interpretation of these structures for instance concerning the stability of the climate system is therefore doubtful. Gene interaction networks for example are often constructed using partial correlations (Wu et al. 2003), which makes it possible to distinguish between direct and indirect dependencies. Although a high value of partial correlation does not guarantee causality it is a step in the direction of measuring causal dependencies. This approach is known as Gaussian Graphical Models, GGMs. For high dimensional datasets such as climate data partial correlations can be obtained by calculating the precision matrix, the inverse covariance matrix. Since the maximum likelihood estimates of covariance matrices of climate datasets are singular the precision matrices can only be estimated for example by using the
Unusual Inorganic Biradicals: A Theoretical Analysis
Miliordos, Evangelos; Ruedenberg, Klaus; Xantheas, Sotiris S.
2013-05-27
Triatomic ions in the series FX_{2}^{+}, where X = O, S, Se, Te and Po are the terminal atoms, exhibit unusually high biradical characters (0.76 < β < 0.92), as measured from the analysis of Multi-Reference Configuration Interaction (MRCI) wavefunctions. Candidates in this series have the largest biradical character among the homologous, 18 valence electron CX_{2}^{2-}, NX_{2}^{-}, X_{3} and OX_{2} (X = O, S, Se, Te and Po) systems. In the same scale the biradical character of ozone (O_{3}) is just 0.19, whereas that of trimethylenemethane [C(CH_{2})_{3}] is 0.97 (β=1 for an "ideal" biradical). For the 24 electron XO_{2} series, consisting of molecules with two oxygen atoms and a moiety X that is isoelectronic to oxygen, i.e. X= CH_{2}, NH, O, F^{+}, the singlet (S) state is lower than the triplet (T) one and the S-T splitting as well the barrier between their "open" and "ring" configurations was found to depend linearly with the inverse of the biradical character.
Development of Novel, Simple Multianalyte Sensors for Remote Environmental Analysis
Professor Sanford A. Asher
2003-02-18
Advancement of our polymerized crystalline colloidal array chemical sensing technology. They have dramatically advanced their polymerized crystalline colloidal array chemical sensing technology. They fabricated nonselective sensors for determining pH and ionic strength. They also developed selective sensors for glucose and organophosphorus mimics of nerve gas agents. They developed a trace sensor for cations in water which utilized a novel crosslinking sensing motif. In all of these cases they have been able to theoretically model their sensor response by extending hydrogel volume phase transition theory. They also developed transient sampling methods to allow their ion sensing methods to operate at high ionic strengths. They also developed a novel optrode to provide for simple sampling.
Hou, Chen; Amunugama, Kaushalya
2015-07-01
The relationship between energy expenditure and longevity has been a central theme in aging studies. Empirical studies have yielded controversial results, which cannot be reconciled by existing theories. In this paper, we present a simple theoretical model based on first principles of energy conservation and allometric scaling laws. The model takes into considerations the energy tradeoffs between life history traits and the efficiency of the energy utilization, and offers quantitative and qualitative explanations for a set of seemingly contradictory empirical results. We show that oxidative metabolism can affect cellular damage and longevity in different ways in animals with different life histories and under different experimental conditions. Qualitative data and the linearity between energy expenditure, cellular damage, and lifespan assumed in previous studies are not sufficient to understand the complexity of the relationships. Our model provides a theoretical framework for quantitative analyses and predictions. The model is supported by a variety of empirical studies, including studies on the cellular damage profile during ontogeny; the intra- and inter-specific correlations between body mass, metabolic rate, and lifespan; and the effects on lifespan of (1) diet restriction and genetic modification of growth hormone, (2) the cold and exercise stresses, and (3) manipulations of antioxidant. PMID:26086438
Theoretical analysis on flow characteristics of melt gear pump
NASA Astrophysics Data System (ADS)
Zhao, R. J.; Wang, J. Q.; Kong, F. Y.
2016-05-01
The relationship between Geometric parameters and theoretical flow of melt gear pump is revealed, providing a theoretical basis to melt gear pump design. The paper has an analysis of meshing movement of melt gear pump on the condition of four different tooth numbers, stack movement law and flow ripple. The regulation of flow pulsation coefficient is researched by MATLAB software. The modulus formula of melt gear pump is proposed, consistent with actual situation.
Morphometric analysis of a fresh simple crater on the Moon.
NASA Astrophysics Data System (ADS)
Vivaldi, V.; Ninfo, A.; Massironi, M.; Martellato, E.; Cremonese, G.
In this research we are proposing an innovative method to determine and quantify the morphology of a simple fresh impact crater. Linné is a well preserved impact crater of 2.2 km in diameter, located at 27.7oN 11.8oE, near the western edge of Mare Serenitatis on the Moon. The crater was photographed by the Lunar Orbiter and the Apollo space missions. Its particular morphology may place Linné as the most striking example of small fresh simple crater. Morphometric analysis, conducted on recent high resolution DTM from LROC (NASA), quantitatively confirmed the pristine morphology of the crater, revealing a clear inner layering which highlight a sequence of lava emplacement events.
Simple Analysis of Prolate-Spin Attitude Stability
NASA Astrophysics Data System (ADS)
Kawase, Sei-Ichiro
How can a prolate spacecraft spinning about its axis of minimum moment of inertia be attitude-stabilized by using dual spin? To this question, we find a simple, clear answer. We replace the spacecraft with an equivalent point-mass model and describe its attitude motion as small deviations from its nominal attitude. We show that a friction-like torque applied to the spin axis would reduce wobble motions, and that a similar torque is generated by a wobble damper on a de-spun platform. Thus, we derive a simple attitude-stability theory using minimal mathematical analysis, and this theory is applicable to the spin stabilization of geosynchronous communication spacecraft.
Bioimpedance Analysis: A Guide to Simple Design and Implementation
Aroom, Kevin R.; Harting, Matthew T.; Cox, Charles S.; Radharkrishnan, Ravi S.; Smith, Carter; Gill, Brijesh S.
2013-01-01
Background Bioimpedance analysis has found utility in many fields of medical research, yet instrumentation can be expensive and/or complicated to build. Advancements in electronic component design and equipment allow for simple bioimpedance analysis using equipment now commonly found in an engineering lab, combined with a few components exclusive to impedance analysis. Materials and methods A modified Howland bridge circuit was designed on a small circuit board with connections for power and bioimpedance probes. A programmable function generator and an oscilloscope were connected to a laptop computer and were tasked to drive and receive data from the circuit. The software then parsed the received data and inserted it into a spreadsheet for subsequent data analysis. The circuit was validated by testing its current output over a range of frequencies and comparing measured values of impedance across a test circuit to expected values. Results The system was validated over frequencies between 1 and 100 kHz. Maximum fluctuation in current was on the order of micro-Amperes. Similarly, the measured value of impedance in a test circuit followed the pattern of actual impedance over the range of frequencies measured. Conclusions Contemporary generation electronic measurement equipment provides adequate levels of connectivity and programmability to rapidly measure and record data for bioimpedance research. These components allow for the rapid development of a simple but accurate bioimpedance measurement system that can be assembled by individuals with limited knowledge of electronics or programming. PMID:18805550
The Theoretical Foundation of Sensitivity Analysis for GPS
NASA Astrophysics Data System (ADS)
Shikoska, U.; Davchev, D.; Shikoski, J.
2008-10-01
In this paper the equations of sensitivity analysis are derived and established theoretical underpinnings for the analyses. Paper propounds a land-vehicle navigation concepts and definition for sensitivity analysis. Equations of sensitivity analysis are presented for a linear Kalman filter and case study is given to illustrate the use of sensitivity analysis to the reader. At the end of the paper, extensions that are required for this research are made to the basic equations of sensitivity analysis specifically; the equations of sensitivity analysis are re-derived for a linearized Kalman filter.
Mode Deactivation Therapy (MDT) Family Therapy: A Theoretical Case Analysis
ERIC Educational Resources Information Center
Apsche, J. A.; Ward Bailey, S. R.
2004-01-01
This case study presents a theoretical analysis of implementing mode deactivation therapy (MDT) (Apsche & Ward Bailey, 2003) family therapy with a 13 year old Caucasian male. MDT is a form of cognitive behavioral therapy (CBT) that combines the balance of dialectical behavior therapy (DBT) (Linehan, 1993), the importance of perception from…
Theoretical Notes on the Sociological Analysis of School Reform Networks
ERIC Educational Resources Information Center
Ladwig, James G.
2014-01-01
Nearly two decades ago, Ladwig outlined the theoretical and methodological implications of Bourdieu's concept of the social field for sociological analyses of educational policy and school reform. The current analysis extends this work to consider the sociological import of one of the most ubiquitous forms of educational reform found around…
NASA Technical Reports Server (NTRS)
Hakkinen, Raimo J; Richardson, A S , Jr
1957-01-01
Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.
Game theoretic analysis of physical protection system design
Canion, B.; Schneider, E.; Bickel, E.; Hadlock, C.; Morton, D.
2013-07-01
The physical protection system (PPS) of a fictional small modular reactor (SMR) facility have been modeled as a platform for a game theoretic approach to security decision analysis. To demonstrate the game theoretic approach, a rational adversary with complete knowledge of the facility has been modeled attempting a sabotage attack. The adversary adjusts his decisions in response to investments made by the defender to enhance the security measures. This can lead to a conservative physical protection system design. Since defender upgrades were limited by a budget, cost benefit analysis may be conducted upon security upgrades. One approach to cost benefit analysis is the efficient frontier, which depicts the reduction in expected consequence per incremental increase in the security budget.
A simple model of hysteresis behavior using spreadsheet analysis
NASA Astrophysics Data System (ADS)
Ehrmann, A.; Blachowicz, T.
2015-01-01
Hysteresis loops occur in many scientific and technical problems, especially as field dependent magnetization of ferromagnetic materials, but also as stress-strain-curves of materials measured by tensile tests including thermal effects, liquid-solid phase transitions, in cell biology or economics. While several mathematical models exist which aim to calculate hysteresis energies and other parameters, here we offer a simple model for a general hysteretic system, showing different hysteresis loops depending on the defined parameters. The calculation which is based on basic spreadsheet analysis plus an easy macro code can be used by students to understand how these systems work and how the parameters influence the reactions of the system on an external field. Importantly, in the step-by-step mode, each change of the system state, compared to the last step, becomes visible. The simple program can be developed further by several changes and additions, enabling the building of a tool which is capable of answering real physical questions in the broad field of magnetism as well as in other scientific areas, in which similar hysteresis loops occur.
Barringer, J.L.; Johnsson, P.A.
1996-01-01
Titrations for alkalinity and acidity using the technique described by Gran (1952, Determination of the equivalence point in potentiometric titrations, Part II: The Analyst, v. 77, p. 661-671) have been employed in the analysis of low-pH natural waters. This report includes a synopsis of the theory and calculations associated with Gran's technique and presents a simple and inexpensive method for performing alkalinity and acidity determinations. However, potential sources of error introduced by the chemical character of some waters may limit the utility of Gran's technique. Therefore, the cost- and time-efficient method for performing alkalinity and acidity determinations described in this report is useful for exploring the suitability of Gran's technique in studies of water chemistry.
Laney, Jonathan; Adalı, Tülay; McCombe Waller, Sandy; Westlake, Kelly P
2015-01-01
The assessment of neuroplasticity after stroke through functional magnetic resonance imaging (fMRI) analysis is a developing field where the objective is to better understand the neural process of recovery and to better target rehabilitation interventions. The challenge in this population stems from the large amount of individual spatial variability and the need to summarize entire brain maps by generating simple, yet discriminating features to highlight differences in functional connectivity. Independent vector analysis (IVA) has been shown to provide superior performance in preserving subject variability when compared with widely used methods such as group independent component analysis. Hence, in this paper, graph-theoretical (GT) analysis is applied to IVA-generated components to effectively exploit the individual subjects' connectivity to produce discriminative features. The analysis is performed on fMRI data collected from individuals with chronic stroke both before and after a 6-week arm and hand rehabilitation intervention. Resulting GT features are shown to capture connectivity changes that are not evident through direct comparison of the group t-maps. The GT features revealed increased small worldness across components and greater centrality in key motor networks as a result of the intervention, suggesting improved efficiency in neural communication. Clinically, these results bring forth new possibilities as a means to observe the neural processes underlying improvements in motor function. PMID:26106554
Cost analysis and outcomes of simple elbow dislocations
Panteli, Michalis; Pountos, Ippokratis; Kanakaris, Nikolaos K; Tosounidis, Theodoros H; Giannoudis, Peter V
2015-01-01
AIM: To evaluate the management, clinical outcome and cost implications of three different treatment regimes for simple elbow dislocations. METHODS: Following institutional board approval, we performed a retrospective review of all consecutive patients treated for simple elbow dislocations in a Level I trauma centre between January 2008 and December 2010. Based on the length of elbow immobilisation (LOI), patients were divided in three groups (Group I, < 2 wk; Group II, 2-3 wk; and Group III, > 3 wk). Outcome was considered satisfactory when a patient could achieve a pain-free range of motion ≥ 100° (from 30° to 130°). The associated direct medical costs for the treatment of each patient were then calculated and analysed. RESULTS: We identified 80 patients who met the inclusion criteria. Due to loss to follow up, 13 patients were excluded from further analysis, leaving 67 patients for the final analysis. The mean LOI was 14 d (median 15 d; range 3-43 d) with a mean duration of hospital engagement of 67 d (median 57 d; range 10-351 d). Group III (prolonged immobilisation) had a statistically significant worse outcome in comparison to Group I and II (P = 0.04 and P = 0.01 respectively); however, there was no significant difference in the outcome between groups I and II (P = 0.30). No statistically significant difference in the direct medical costs between the groups was identified. CONCLUSION: The length of elbow immobilization doesn’t influence the medical cost; however immobilisation longer than three weeks is associated with persistent stiffness and a less satisfactory clinical outcome. PMID:26301180
An analysis of morphologic variation in simple lunar craters
NASA Astrophysics Data System (ADS)
Ravine, M. A.; Grieve, R. A. F.
Previous photogeologic classification of lunar craters have differentiated them into various morphologic types. In an attempt to identify the physical factors responsible for these morphologic variations, this study examined 44 fresh, simple lunar craters between 1.1 and 14 km in diameter on the maria. Photogeologic analysis was performed using Apollo stereo panoramic photography, while a quantitative analysis of cross-sectional shape was done using Fourier analysis. These analyses showed that the sample could not be split into two distinct types (flat- and round-floored) as had been done previously. The two crater types at best represent end-members of a distribution of morphologies. Some correlation was found between the degree of relative degradation and floor roundness, implying that flat floors are primary and round floors are degradational features. No difference was found between the average depth-to-diameter ratio of flat- and round-floored craters, indicating that the factor of two variation in depth-to-diameter ratio in this sample of fresh craters is a primary morphologic feature and that minor degradation of fresh craters has no significant effect on average crater depth.
Image inpainting: theoretical analysis and comparison of algorithms
NASA Astrophysics Data System (ADS)
King, Emily J.; Kutyniok, Gitta; Lim, Wang-Q.
2013-09-01
An issue in data analysis is that of incomplete data, for example a photograph with scratches or seismic data collected with fewer than necessary sensors. There exists a unified approach to solving this problem and that of data separation: namely, minimizing the norm of the analysis (rather than synthesis) coefficients with respect to particular frame(s).There have been a number of successful applications of this method recently. Analyzing this method using the concept of clustered sparsity leads to theoretical bounds and results, which will be presented. Furthermore, necessary conditions for the frames to lead to sufficiently good solutions will be shown, and this theoretical framework will be use to show that shearlets are able to inpaint larger gaps than wavelets. Finally, the results of numerical experiments comparing this approach to inpainting to numerous others will be presented.
Wissler, Eugene H; Havenith, George
2009-03-01
Overall resistances for heat and vapor transport in a multilayer garment depend on the properties of individual layers and the thickness of any air space between layers. Under uncomplicated, steady-state conditions, thermal and mass fluxes are uniform within the garment, and the rate of transport is simply computed as the overall temperature or water concentration difference divided by the appropriate resistance. However, that simple computation is not valid under cool ambient conditions when the vapor permeability of the garment is low, and condensation occurs within the garment. Several recent studies have measured heat and vapor transport when condensation occurs within the garment (Richards et al. in Report on Project ThermProject, Contract No. G6RD-CT-2002-00846, 2002; Havenith et al. in J Appl Physiol 104:142-149, 2008). In addition to measuring cooling rates for ensembles when the skin was either wet or dry, both studies employed a flat-plate apparatus to measure resistances of individual layers. Those data provide information required to define the properties of an ensemble in terms of its individual layers. We have extended the work of previous investigators by developing a rather simple technique for analyzing heat and water vapor transport when condensation occurs within a garment. Computed results agree well with experimental results reported by Richards et al. (Report on Project ThermProject, Contract No. G6RD-CT-2002-00846, 2002) and Havenith et al. (J Appl Physiol 104:142-149, 2008). We discuss application of the method to human subjects for whom the rate of sweat secretion, instead of the partial pressure of water on the skin, is specified. Analysis of a more complicated five-layer system studied by Yoo and Kim (Text Res J 78:189-197, 2008) required an iterative computation based on principles defined in this paper. PMID:19125281
Dynamic and Thermodynamic Analysis of a Simple Model of DNA
NASA Astrophysics Data System (ADS)
Techera, Mario Isaac Felix
1991-02-01
A new simple model of DNA is presented based on the results of lattice dynamics (LD) calculations in conjunction with the modified self-consistent phonon approximation (MSPA) done on a detailed model of DNA homopolymers. The model emphasizes the intrinsic nonlinearities present in the hydrogen-bonded duplex. The impetus for introducing the simplified model is to analyze the importance of the nonlinearities in the dynamics that lead to denaturation. An initial analysis is done on the possible dynamical excitations that can exist in the system due to the hydrogen bond (HB) nonlinearities. It is found that in a certain regime of base-pair motion, the nonlinearities can prevent dissipation of wave packets and thus suggesting the possibility of energy transfer along the molecule. What is also found, is the ability of the nonlinearities to "pin" excitations on the lattice thus suggesting a possible mechanism for localizing energy along the molecule for biologically significant periods of time. This analysis is done on a "cold" chain, i.e. at T = 0 K. In the latter part of this thesis, this model is shown to be thermodynamically unstable under certain circumstances. This instability is analyzed and general conclusions are drawn concerning the thermodynamics of any interaction similar to the ones used in the present case. As a result of this instability the thermodynamic analysis is done in nonequilibrium situations using stochastic methods to simulate a heat bath. Numerical calculations are performed to study the dissociation of the molecule and the possible effects of the thermal bath on the dynamical excitations mentioned in the previous paragraph. It is found that the dissociation time is very long at room temperature for long molecules.
Python for Information Theoretic Analysis of Neural Data
Ince, Robin A. A.; Petersen, Rasmus S.; Swan, Daniel C.; Panzeri, Stefano
2008-01-01
Information theory, the mathematical theory of communication in the presence of noise, is playing an increasingly important role in modern quantitative neuroscience. It makes it possible to treat neural systems as stochastic communication channels and gain valuable, quantitative insights into their sensory coding function. These techniques provide results on how neurons encode stimuli in a way which is independent of any specific assumptions on which part of the neuronal response is signal and which is noise, and they can be usefully applied even to highly non-linear systems where traditional techniques fail. In this article, we describe our work and experiences using Python for information theoretic analysis. We outline some of the algorithmic, statistical and numerical challenges in the computation of information theoretic quantities from neural data. In particular, we consider the problems arising from limited sampling bias and from calculation of maximum entropy distributions in the presence of constraints representing the effects of different orders of interaction in the system. We explain how and why using Python has allowed us to significantly improve the speed and domain of applicability of the information theoretic algorithms, allowing analysis of data sets characterized by larger numbers of variables. We also discuss how our use of Python is facilitating integration with collaborative databases and centralised computational resources. PMID:19242557
NASA Astrophysics Data System (ADS)
Loubriel, G. M.
1980-03-01
The interaction between small molecules and transition metal atoms is investigated. Nitric oxide adsorbed on clean metal surfaces and transition metal complexes like Cr(NO)4, Cr(CO)6 and Ni(CO)4 were studied. The approach used was to learn as much as possible about the electronic structure and bonding in carbonyls and nitrosyls where the atomic positions were known and use this knowledge to help determine the bonding geometry of NO adsorbed on Ni(100). In addition to the analysis of photoemission, theoretical calculations of electronic structure via the self-consistent field X alpha multiple scattering technique were performed. The bonding of NO to transition metal atoms occurs mainly through the interaction of the levels of the metal atom and the 2 pi level of NO. In Cr(NO)4 this bonding is reflected in a charge transfer of about half an electron into the 2 pi level of each one of the NO molecules. The results of first principles calculations of shakeup energies and shakeup intensities for the photo-electron spectra of carbonyls and nitrosyls are reported. The mechanisms by which core holes produced by the photo-excitation are screened are discussed. The results for Ni(CO)4 and Cr(NO)4 are in excellent agreement with experiment.
A simple and inexpensive device for biofilm analysis.
Almshawit, Hala; Macreadie, Ian; Grando, Danilla
2014-03-01
The Calgary Biofilm Device (CBD) has been described as a technology for the rapid and reproducible assay of biofilm susceptibilities to antibiotics. In this study a simple and inexpensive alternative to the CBD was developed from polypropylene (PP) microcentrifuge tubes and pipette tip boxes. The utility of the device was demonstrated using Candida glabrata, a yeast that can develop antimicrobial-resistant biofilm communities. Biofilms of C. glabrata were formed on the outside surface of microcentrifuge tubes and examined by quantitative analysis and scanning electron microscopy. Growth of three C. glabrata strains, including a clinical isolate, demonstrated that biofilms could be formed on the microcentrifuge tubes. After 24 h incubation the three C. glabrata strains produced biofilms that were recovered into cell suspension and quantified. The method was found to produce uniform and reproducible results with no significant differences between biofilms formed on PP tubes incubated in various compartments of the device. In addition, the difference between maximum and minimum counts for each strain was comparable to those which have been reported for the CBD device. PMID:24389040
Global analysis of a 'simple' proteome : methanoccus jannaschii.
Giometti, C. S.; Reich, C.; Tollaksen, S.; Babnigg, G.; Lim, H.; Zhu, W.; Yates, J., III; Olsen, G.; Biosciences Division; Univ. of Illinois; The Scripps Inst.
2002-12-25
The completed genome of Methanococcus jannaschii, including the main chromosome and two extra-chromosomal elements, predicts a proteome comprised of 1783 proteins. How many of those proteins are expressed at any given time and the relative abundance of the expressed proteins, however, cannot be predicted solely from the genome sequence. Two-dimensional gel electrophoresis coupled with peptide mass spectrometry is being used to identify the proteins expressed by M. jannaschii cells grown under different conditions as part of an effort to correlate protein expression with regulatory mechanisms. Here we describe the identification of 170 of the most abundant proteins found in total lysates of M. jannaschii grown under optimal fermentation conditions. To optimize the number of proteins detected, two different protein specific stains (Coomassie Blue R250 or silver nitrate) and two different first dimension separation methods (isoelectric focusing or nonequilibrium pH gradient electrophoresis) were used. Thirty-two percent of the proteins identified are annotated as hypothetical (21% conserved hypothetical and 11% hypothetical), 21% are enzymes involved in energy metabolism, 12% are proteins required for protein synthesis, and the remainder include proteins necessary for intermediary metabolism, cell division, and cell structure. Evidence of post-translational modification of numerous M. jannaschii proteins has been found, as well as indications of incomplete dissociation of protein-protein complexes. These results demonstrate the complexity of proteome analysis even when dealing with a relatively simple genome.
Evolution Analysis of Simple Sequence Repeats in Plant Genome
Qin, Zhen; Wang, Yanping; Wang, Qingmei; Li, Aixian; Hou, Fuyun; Zhang, Liming
2015-01-01
Simple sequence repeats (SSRs) are widespread units on genome sequences, and play many important roles in plants. In order to reveal the evolution of plant genomes, we investigated the evolutionary regularities of SSRs during the evolution of plant species and the plant kingdom by analysis of twelve sequenced plant genome sequences. First, in the twelve studied plant genomes, the main SSRs were those which contain repeats of 1–3 nucleotides combination. Second, in mononucleotide SSRs, the A/T percentage gradually increased along with the evolution of plants (except for P. patens). With the increase of SSRs repeat number the percentage of A/T in C. reinhardtii had no significant change, while the percentage of A/T in terrestrial plants species gradually declined. Third, in dinucleotide SSRs, the percentage of AT/TA increased along with the evolution of plant kingdom and the repeat number increased in terrestrial plants species. This trend was more obvious in dicotyledon than monocotyledon. The percentage of CG/GC showed the opposite pattern to the AT/TA. Forth, in trinucleotide SSRs, the percentages of combinations including two or three A/T were in a rising trend along with the evolution of plant kingdom; meanwhile with the increase of SSRs repeat number in plants species, different species chose different combinations as dominant SSRs. SSRs in C. reinhardtii, P. patens, Z. mays and A. thaliana showed their specific patterns related to evolutionary position or specific changes of genome sequences. The results showed that, SSRs not only had the general pattern in the evolution of plant kingdom, but also were associated with the evolution of the specific genome sequence. The study of the evolutionary regularities of SSRs provided new insights for the analysis of the plant genome evolution. PMID:26630570
Theoretical analysis of quantum ghost imaging through turbulence
Chan, Kam Wai Clifford; Simon, D. S.; Sergienko, A. V.; Hardy, Nicholas D.; Shapiro, Jeffrey H.; Dixon, P. Ben; Howland, Gregory A.; Howell, John C.; Eberly, Joseph H.; O'Sullivan, Malcolm N.; Rodenburg, Brandon; Boyd, Robert W.
2011-10-15
Atmospheric turbulence generally affects the resolution and visibility of an image in long-distance imaging. In a recent quantum ghost imaging experiment [P. B. Dixon et al., Phys. Rev. A 83, 051803 (2011)], it was found that the effect of the turbulence can nevertheless be mitigated under certain conditions. This paper gives a detailed theoretical analysis to the setup and results reported in the experiment. Entangled photons with a finite correlation area and a turbulence model beyond the phase screen approximation are considered.
A Simple Buckling Analysis Method for Airframe Composite Stiffened Panel by Finite Strip Method
NASA Astrophysics Data System (ADS)
Tanoue, Yoshitsugu
Carbon fiber reinforced plastics (CFRP) have been used in structural components for newly developed aircraft and spacecraft. The main structures of an airframe, such as the fuselage and wings, are essentially composed of stiffened panels. Therefore, in the structural design of airframes, it is important to evaluate the buckling strength of the composite stiffened panels. Widely used finite element method (FEM) can analyzed any stiffened panel shape with various boundary conditions. However, in the early phase of airframe development, many studies are required in structural design prior to carrying out detail drawing. In this phase, performing structural analysis using only FEM may not be very efficient. This paper describes a simple buckling analysis method for composite stiffened panels, which is based on finite strip method. This method can deal with isotropic and anisotropic laminated plates and shells with several boundary conditions. The accuracy of this method was verified by comparing it with theoretical analysis and FEM analysis (NASTRAN). It has been observed that the buckling coefficients calculated via the present method are in agreement with results found by detail analysis methods. Consequently, this method is designed to be an effective calculation tool for the buckling analysis in the early phases of airframe design.
Theoretical analysis of dynamic processes for interacting molecular motors
NASA Astrophysics Data System (ADS)
Teimouri, Hamid; Kolomeisky, Anatoly B.; Mehrabiani, Kareem
2015-02-01
Biological transport is supported by the collective dynamics of enzymatic molecules that are called motor proteins or molecular motors. Experiments suggest that motor proteins interact locally via short-range potentials. We investigate the fundamental role of these interactions by carrying out an analysis of a new class of totally asymmetric exclusion processes, in which interactions are accounted for in a thermodynamically consistent fashion. This allows us to explicitly connect microscopic features of motor proteins with their collective dynamic properties. A theoretical analysis that combines various mean-field calculations and computer simulations suggests that the dynamic properties of molecular motors strongly depend on the interactions, and that the correlations are stronger for interacting motor proteins. Surprisingly, it is found that there is an optimal strength of interactions (weak repulsion) that leads to a maximal particle flux. It is also argued that molecular motor transport is more sensitive to attractive interactions. Applications of these results for kinesin motor proteins are discussed.
Theoretical analysis of the performance of a foam fractionation column
Tobin, S. T.; Weaire, D.; Hutzler, S.
2014-01-01
A model system for theory and experiment which is relevant to foam fractionation consists of a column of foam moving through an inverted U-tube between two pools of surfactant solution. The foam drainage equation is used for a detailed theoretical analysis of this process. In a previous paper, we focused on the case where the lengths of the two legs are large. In this work, we examine the approach to the limiting case (i.e. the effects of finite leg lengths) and how it affects the performance of the fractionation column. We also briefly discuss some alternative set-ups that are of interest in industry and experiment, with numerical and analytical results to support them. Our analysis is shown to be generally applicable to a range of fractionation columns. PMID:24808752
Theoretical analysis and applications in inverse T-shape structure.
Li, Boxun; Li, Hongjian; Zeng, Lili; Zhan, Shiping; He, Zhihui; Chen, Zhiquan; Xu, Hui
2016-05-01
An inverse T-shape structure, consisting of a bus waveguide coupled with two perpendicular rectangular cavities, has been investigated numerically and theoretically. The position of the transparency window can be manipulated by adjusting the lateral displacement between the two perpendicular cavities. The effects of changing different structural parameters on the transmission features are investigated in detail. The results indicate that the length of two cavities play important roles in optimizing optical response. Finally, two simple applications based on the inverse T-shape structure are briefly discussed. The findings demonstrate that the first- and second-order modes can be separated without interference, and the sensitivity of the inverse T-shape is as high as 1750 nm per refractive index unit (RIU); the corresponding figure of merit (FOM) reaches up to 77.1 RIU^{-1}, which is higher than in previous reports. The plasmonic configuration possesses the advantages of easy fabrication, compactness, and higher sensitivity as well as higher FOM, which will greatly benefit the compact plasmonic filter and high-sensitivity nanosensor in highly integrated optical devices. PMID:27140878
NASA Astrophysics Data System (ADS)
Livshts, Mikhail A.; Khomyakova, Elena; Evtushenko, Evgeniy G.; Lazarev, Vassili N.; Kulemin, Nikolay A.; Semina, Svetlana E.; Generozov, Edward V.; Govorun, Vadim M.
2015-11-01
Exosomes, small (40-100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for “fixed-angle” rotors. For both types of rotors - “swinging bucket” and “fixed-angle” - we express the theoretically expected proportion of pelleted vesicles of a given size and the “cut-off” size of completely sedimented vesicles as dependent on the centrifugation force and duration and the sedimentation path-lengths. The proper centrifugation conditions can be selected using relatively simple theoretical estimates of the “cut-off” sizes of vesicles. Experimental verification on exosomes isolated from HT29 cell culture supernatant confirmed the main theoretical statements. Measured by the nanoparticle tracking analysis (NTA) technique, the concentration and size distribution of the vesicles after centrifugation agree with those theoretically expected. To simplify this “cut-off”-size-based adjustment of centrifugation protocol for any rotor, we developed a web-calculator.
Livshits, Mikhail A; Livshts, Mikhail A; Khomyakova, Elena; Evtushenko, Evgeniy G; Lazarev, Vassili N; Kulemin, Nikolay A; Semina, Svetlana E; Generozov, Edward V; Govorun, Vadim M
2015-01-01
Exosomes, small (40-100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for "fixed-angle" rotors. For both types of rotors--"swinging bucket" and "fixed-angle"--we express the theoretically expected proportion of pelleted vesicles of a given size and the "cut-off" size of completely sedimented vesicles as dependent on the centrifugation force and duration and the sedimentation path-lengths. The proper centrifugation conditions can be selected using relatively simple theoretical estimates of the "cut-off" sizes of vesicles. Experimental verification on exosomes isolated from HT29 cell culture supernatant confirmed the main theoretical statements. Measured by the nanoparticle tracking analysis (NTA) technique, the concentration and size distribution of the vesicles after centrifugation agree with those theoretically expected. To simplify this "cut-off"-size-based adjustment of centrifugation protocol for any rotor, we developed a web-calculator. PMID:26616523
Livshts, Mikhail A.; Khomyakova, Elena; Evtushenko, Evgeniy G.; Lazarev, Vassili N.; Kulemin, Nikolay A.; Semina, Svetlana E.; Generozov, Edward V.; Govorun, Vadim M.
2015-01-01
Exosomes, small (40–100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for “fixed-angle” rotors. For both types of rotors – “swinging bucket” and “fixed-angle” – we express the theoretically expected proportion of pelleted vesicles of a given size and the “cut-off” size of completely sedimented vesicles as dependent on the centrifugation force and duration and the sedimentation path-lengths. The proper centrifugation conditions can be selected using relatively simple theoretical estimates of the “cut-off” sizes of vesicles. Experimental verification on exosomes isolated from HT29 cell culture supernatant confirmed the main theoretical statements. Measured by the nanoparticle tracking analysis (NTA) technique, the concentration and size distribution of the vesicles after centrifugation agree with those theoretically expected. To simplify this “cut-off”-size-based adjustment of centrifugation protocol for any rotor, we developed a web-calculator. PMID:26616523
Theoretical analysis of hot electron dynamics in nanorods.
Kumarasinghe, Chathurangi S; Premaratne, Malin; Bao, Qiaoliang; Agrawal, Govind P
2015-01-01
Localised surface plasmons create a non-equilibrium high-energy electron gas in nanostructures that can be injected into other media in energy harvesting applications. Here, we derive the rate of this localised-surface-plasmon mediated generation of hot electrons in nanorods and the rate of injecting them into other media by considering quantum mechanical motion of the electron gas. Specifically, we use the single-electron wave function of a particle in a cylindrical potential well and the electric field enhancement factor of an elongated ellipsoid to derive the energy distribution of electrons after plasmon excitation. We compare the performance of nanorods with equivolume nanoparticles of other shapes such as nanospheres and nanopallets and report that nanorods exhibit significantly better performance over a broad spectrum. We present a comprehensive theoretical analysis of how different parameters contribute to efficiency of hot-electron harvesting in nanorods and reveal that increasing the aspect ratio can increase the hot-electron generation and injection, but the volume shows an inverse dependency when efficiency per unit volume is considered. Further, the electron thermalisation time shows much less influence on the injection rate. Our derivations and results provide the much needed theoretical insight for optimization of hot-electron harvesting process in highly adaptable metallic nanorods. PMID:26202823
Theoretical analysis of hot electron dynamics in nanorods
Kumarasinghe, Chathurangi S.; Premaratne, Malin; Agrawal, Govind P.
2015-01-01
Localised surface plasmons create a non-equilibrium high-energy electron gas in nanostructures that can be injected into other media in energy harvesting applications. Here, we derive the rate of this localised-surface-plasmon mediated generation of hot electrons in nanorods and the rate of injecting them into other media by considering quantum mechanical motion of the electron gas. Specifically, we use the single-electron wave function of a particle in a cylindrical potential well and the electric field enhancement factor of an elongated ellipsoid to derive the energy distribution of electrons after plasmon excitation. We compare the performance of nanorods with equivolume nanoparticles of other shapes such as nanospheres and nanopallets and report that nanorods exhibit significantly better performance over a broad spectrum. We present a comprehensive theoretical analysis of how different parameters contribute to efficiency of hot-electron harvesting in nanorods and reveal that increasing the aspect ratio can increase the hot-electron generation and injection, but the volume shows an inverse dependency when efficiency per unit volume is considered. Further, the electron thermalisation time shows much less influence on the injection rate. Our derivations and results provide the much needed theoretical insight for optimization of hot-electron harvesting process in highly adaptable metallic nanorods. PMID:26202823
Analysis of the theoretical bias in dark matter direct detection
Catena, Riccardo
2014-09-01
Fitting the model ''A'' to dark matter direct detection data, when the model that underlies the data is ''B'', introduces a theoretical bias in the fit. We perform a quantitative study of the theoretical bias in dark matter direct detection, with a focus on assumptions regarding the dark matter interactions, and velocity distribution. We address this problem within the effective theory of isoscalar dark matter-nucleon interactions mediated by a heavy spin-1 or spin-0 particle. We analyze 24 benchmark points in the parameter space of the theory, using frequentist and Bayesian statistical methods. First, we simulate the data of future direct detection experiments assuming a momentum/velocity dependent dark matter-nucleon interaction, and an anisotropic dark matter velocity distribution. Then, we fit a constant scattering cross section, and an isotropic Maxwell-Boltzmann velocity distribution to the simulated data, thereby introducing a bias in the analysis. The best fit values of the dark matter particle mass differ from their benchmark values up to 2 standard deviations. The best fit values of the dark matter-nucleon coupling constant differ from their benchmark values up to several standard deviations. We conclude that common assumptions in dark matter direct detection are a source of potentially significant bias.
DEVELOPMENT OF NOVEL, SIMPLE MULTIANALYTE SENSORS FOR REMOTE ENVIRONMENTAL ANALYSIS
We will develop simple, inexpensive new chemical sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of environmental pollutants such as cations of Pb, U, Pu, Sr, Hg, Cs, Co as well as other speci...
Two-dimensional electronic spectroscopy using incoherent light: theoretical analysis.
Turner, Daniel B; Howey, Dylan J; Sutor, Erika J; Hendrickson, Rebecca A; Gealy, M W; Ulness, Darin J
2013-07-25
Electronic energy transfer in photosynthesis occurs over a range of time scales and under a variety of intermolecular coupling conditions. Recent work has shown that electronic coupling between chromophores can lead to coherent oscillations in two-dimensional electronic spectroscopy measurements of pigment-protein complexes measured with femtosecond laser pulses. A persistent issue in the field is to reconcile the results of measurements performed using femtosecond laser pulses with physiological illumination conditions. Noisy-light spectroscopy can begin to address this question. In this work we present the theoretical analysis of incoherent two-dimensional electronic spectroscopy, I((4)) 2D ES. Simulations reveal diagonal peaks, cross peaks, and coherent oscillations similar to those observed in femtosecond two-dimensional electronic spectroscopy experiments. The results also expose fundamental differences between the femtosecond-pulse and noisy-light techniques; the differences lead to new challenges and new opportunities. PMID:23176195
A theoretical analysis of vacuum arc thruster performance
NASA Technical Reports Server (NTRS)
Polk, James E.; Sekerak, Mike; Ziemer, John K.; Schein, Jochen; Qi, Niansheng; Binder, Robert; Anders, Andre
2001-01-01
In vacuum arc discharges the current is conducted through vapor evaporated from the cathode surface. In these devices very dense, highly ionized plasmas can be created from any metallic or conducting solid used as the cathode. This paper describes theoretical models of performance for several thruster configurations which use vacuum arc plasma sources. This analysis suggests that thrusters using vacuum arc sources can be operated efficiently with a range of propellant options that gives great flexibility in specific impulse. In addition, the efficiency of plasma production in these devices appears to be largely independent of scale because the metal vapor is ionized within a few microns of the cathode electron emission sites, so this approach is well-suited for micropropulsion.
Theoretical analysis of sound transmission loss through graphene sheets
Natsuki, Toshiaki; Ni, Qing-Qing
2014-11-17
We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials.
[Theoretical analysis of recompression-based therapies of decompression illness].
Nikolaev, V P; Sokolov, G M; Komarevtsev, V N
2011-01-01
Theoretical analysis is concerned with the benefits of oxygen, air and nitrogen-helium-oxygen recompression schedules used to treat decompression illness in divers. Mathematical modeling of tissue bubbles dynamics during diving shows that one-hour oxygen recompression to 200 kPa does not diminish essentially the size of bubble enclosed in a layer that reduces tenfold the intensity of gas diffusion from bubbles. However, these bubbles dissolve fully in all the body tissues equally after 2-hr. air compression to 800 kPa and ensuing 2-d decompression by the Russian navy tables, and 1.5-hr. N-He-O2 compression to this pressure followed by 5-day decompression. The overriding advantage of the gas mixture recompression is that it obviates the narcotic action of nitrogen at the peak of chamber pressure and does not create dangerous tissue supersaturation and conditions for emergence of large bubbles at the end of decompression. PMID:21970044
A theoretical analysis of sliding of rough surfaces
NASA Astrophysics Data System (ADS)
Walsh, J. B.
2003-08-01
I used a model proposed by [1966], who analyzed closure between a rough surface and a smooth surface under normal stress, to analyze the growth of slip under increasing shear stress, normal stress remaining constant. The two bodies are elastic half-spaces, one rough and one smooth, and Coulomb friction resists slip at sliding contacts. The elastic and dissipative components of the constitutive relation in shear depend upon statistical parameters which describe the topography of the rough surface. I made a parametric study of the effect of topography on the constitutive relations in shear by comparing a model in which the progress of slip at a contact is continuous with one in which the contact goes discontinuously from "stuck" to sliding. The effect of topography was also studied by assuming that the probability density distribution of the heights of asperities is Gaussian or, alternatively, a negative exponential. These variations in topography produced only minor differences in the constitutive behavior. This insensitivity of the constitutive behavior to differences in the statistical description of the topography arises in part because, only relatively, a small range of asperity heights is active in typical experiments. Work done against friction introduces a dissipative component into the constitutive behavior which I evaluated analytically; I show that the components have a simple graphical construction on plots of shear stress versus displacement developed from experimental observations. Sliding in the reverse sense which occurs when the applied shear stress is relaxed is analyzed, resulting in expressions which describe the shape of hysteresis loops formed when shear stress is cycled. Introducing measurements made on surfaces of specimens of granite and quartzite into the theoretical relations, I found reasonable agreement with experimental data.
Comprehensive analysis of Arabidopsis expression level polymorphisms with simple inheritance.
Plantegenet, Stephanie; Weber, Johann; Goldstein, Darlene R; Zeller, Georg; Nussbaumer, Cindy; Thomas, Jérôme; Weigel, Detlef; Harshman, Keith; Hardtke, Christian S
2009-01-01
In Arabidopsis thaliana, gene expression level polymorphisms (ELPs) between natural accessions that exhibit simple, single locus inheritance are promising quantitative trait locus (QTL) candidates to explain phenotypic variability. It is assumed that such ELPs overwhelmingly represent regulatory element polymorphisms. However, comprehensive genome-wide analyses linking expression level, regulatory sequence and gene structure variation are missing, preventing definite verification of this assumption. Here, we analyzed ELPs observed between the Eil-0 and Lc-0 accessions. Compared with non-variable controls, 5' regulatory sequence variation in the corresponding genes is indeed increased. However, approximately 42% of all the ELP genes also carry major transcription unit deletions in one parent as revealed by genome tiling arrays, representing a >4-fold enrichment over controls. Within the subset of ELPs with simple inheritance, this proportion is even higher and deletions are generally more severe. Similar results were obtained from analyses of the Bay-0 and Sha accessions, using alternative technical approaches. Collectively, our results suggest that drastic structural changes are a major cause for ELPs with simple inheritance, corroborating experimentally observed indel preponderance in cloned Arabidopsis QTL. PMID:19225455
NASA Astrophysics Data System (ADS)
Martínez, José M.; Pappalardo, Rafael R.; Marcos, Enrique Sánchez
1999-01-01
The simplest representation of monoatomic cations in aqueous solutions by means of a sphere with a radius chosen on the basis of a well-defined property (that of the bare ion or its hydrate) is reexamined considering classical molecular dynamics simulations. Two charged sphere-water interaction potentials were employed to mimic the bare and hydrated cation in a sample of 512 water molecules. Short-range interactions of trivalent cations were described by Lennard-Jones potentials which were fitted from ab initio calculations. Five statistically independent runs of 150 ps for each of the trivalent spheres in water were carried out in the microcanonical ensemble. A comparison of structural and dynamical properties of these simple ion models in solution with those of a system containing the Cr3+ hydrate ([Cr(H2O)6]3+) is made to get insight into the size and shape definition of simple ions in water, especially those that are highly charged. Advantages and shortcomings of using simple spherical approaches are discussed on the basis of reference calculations performed with a more rigorous hydrated ion model [J. Phys. Chem. B 102, 3272 (1998)]. The importance of nonspherical shape for the hydrate of highly charged ions is stressed and it is paradoxically shown that when spherical shape is retained, the big sphere representing the hydrate leads to results of ionic solution worse than those obtained with the small sphere. A low-cost method to generate hydrated ion-water interaction potentials taking into account the shape of the ionic aggregate is proposed.
Theoretical analysis of the state of balance in bipedal walking.
Firmani, Flavio; Park, Edward J
2013-04-01
This paper presents a theoretical analysis based on classic mechanical principles of balance of forces in bipedal walking. Theories on the state of balance have been proposed in the area of humanoid robotics and although the laws of classical mechanics are equivalent to both humans and humanoid robots, the resulting motion obtained with these theories is unnatural when compared to normal human gait. Humanoid robots are commonly controlled using the zero moment point (ZMP) with the condition that the ZMP cannot exit the foot-support area. This condition is derived from a physical model in which the biped must always walk under dynamically balanced conditions, making the centre of pressure (CoP) and the ZMP always coincident. On the contrary, humans follow a different strategy characterized by a 'controlled fall' at the end of the swing phase. In this paper, we present a thorough theoretical analysis of the state of balance and show that the ZMP can exit the support area, and its location is representative of the imbalance state characterized by the separation between the ZMP and the CoP. Since humans exhibit this behavior, we also present proof-of-concept results of a single subject walking on an instrumented treadmill at different speeds (from slow 0.7 m/s to fast 2.0 m/s walking with increments of 0.1 m/s) with the motion recorded using an optical motion tracking system. In order to evaluate the experimental results of this model, the coefficient of determination (R2) is used to correlate the measured ground reaction forces and the resultant of inertial and gravitational forces (anteroposterior R² = 0.93, mediolateral R² = 0.89, and vertical R² = 0.86) indicating that there is a high correlation between the measurements. The results suggest that the subject exhibits a complete dynamically balanced gait during slow speeds while experiencing a controlled fall (end of swing phase) with faster speeds. This is quantified with the root-mean-square deviation (RMSD
Theoretical Analysis of the Electron Spiral Toroid Concept
NASA Technical Reports Server (NTRS)
Cambier, Jean-Luc; Micheletti, David A.; Bushnell, Dennis M. (Technical Monitor)
2000-01-01
This report describes the analysis of the Electron Spiral Toroid (EST) concept being promoted by Electron Power Systems Inc. (EPS). The EST is described as a toroidal plasma structure composed Of ion and electron shells. It is claimed that the EST requires little or no external confinement, despite the extraordinarily large energy densities resulting from the self-generating magnetic fields. The present analysis is based upon documentation made available by EPS, a previous description of the model by the Massachusetts Institute of Technology (MIT), and direct discussions with EPS and MIT. It is found that claims of absolute stability and large energy storage capacities of the EST concept have not been substantiated. Notably, it can be demonstrated that the ion fluid is fundamentally unstable. Although various scenarios for ion confinement were subsequently suggested by EPS and MIT, none were found to be plausible. Although the experimental data does not prove the existence of EST configurations, there is undeniable experimental evidence that some type of plasma structures whose characteristics remain to be determined are observed. However, more realistic theoretical models must first be developed to explain their existence and properties before applications of interest to NASA can he assessed and developed.
Simple exact analysis of the standardised mortality ratio.
Liddell, F D
1984-01-01
The standardised mortality ratio is the ratio of deaths observed, D, to those expected, E, on the basis of the mortality rates of some reference population. On the usual assumptions--that D was generated by a Poisson process and that E is based on such large numbers that it can be taken as without error--the long established, but apparently little known, link between the Poisson and chi 2 distributions provides both an exact test of significance and expressions for obtaining exact (1-alpha) confidence limits on the SMR. When a table of the chi 2 distribution gives values for 1-1/2 alpha and 1/2 alpha with the required degrees of freedom, the procedures are not only precise but very simple. When the required values of chi 2 are not tabulated, only slightly less simple procedures are shown to be highly reliable for D greater than 5; they are more reliable for all D and alpha than even the best of three approximate methods. For small D, all approximations can be seriously unreliable. The exact procedures are therefore recommended for use wherever the basic assumptions (Poisson D and fixed E) apply. PMID:6707569
GRETNA: a graph theoretical network analysis toolbox for imaging connectomics
Wang, Jinhui; Wang, Xindi; Xia, Mingrui; Liao, Xuhong; Evans, Alan; He, Yong
2015-01-01
Recent studies have suggested that the brain’s structural and functional networks (i.e., connectomics) can be constructed by various imaging technologies (e.g., EEG/MEG; structural, diffusion and functional MRI) and further characterized by graph theory. Given the huge complexity of network construction, analysis and statistics, toolboxes incorporating these functions are largely lacking. Here, we developed the GRaph thEoreTical Network Analysis (GRETNA) toolbox for imaging connectomics. The GRETNA contains several key features as follows: (i) an open-source, Matlab-based, cross-platform (Windows and UNIX OS) package with a graphical user interface (GUI); (ii) allowing topological analyses of global and local network properties with parallel computing ability, independent of imaging modality and species; (iii) providing flexible manipulations in several key steps during network construction and analysis, which include network node definition, network connectivity processing, network type selection and choice of thresholding procedure; (iv) allowing statistical comparisons of global, nodal and connectional network metrics and assessments of relationship between these network metrics and clinical or behavioral variables of interest; and (v) including functionality in image preprocessing and network construction based on resting-state functional MRI (R-fMRI) data. After applying the GRETNA to a publicly released R-fMRI dataset of 54 healthy young adults, we demonstrated that human brain functional networks exhibit efficient small-world, assortative, hierarchical and modular organizations and possess highly connected hubs and that these findings are robust against different analytical strategies. With these efforts, we anticipate that GRETNA will accelerate imaging connectomics in an easy, quick and flexible manner. GRETNA is freely available on the NITRC website.1 PMID:26175682
Large deviation analysis of a simple information engine.
Maitland, Michael; Grosskinsky, Stefan; Harris, Rosemary J
2015-11-01
Information thermodynamics provides a framework for studying the effect of feedback loops on entropy production. It has enabled the understanding of novel thermodynamic systems such as the information engine, which can be seen as a modern version of "Maxwell's Dæmon," whereby a feedback controller processes information gained by measurements in order to extract work. Here, we analyze a simple model of such an engine that uses feedback control based on measurements to obtain negative entropy production. We focus on the distribution and fluctuations of the information obtained by the feedback controller. Significantly, our model allows an analytic treatment for a two-state system with exact calculation of the large deviation rate function. These results suggest an approximate technique for larger systems, which is corroborated by simulation data. PMID:26651675
A simple flow analysis of diffuser-getter-diffuser systems
Klein, J. E.; Howard, D. W.
2008-07-15
Tritium clean-up systems typically deploy gas processing technologies between stages of palladium-silver (Pd/Ag) diffusers/permeators. The number of diffusers positioned before and after a gas clean-up process to obtain optimal system performance will vary with feed gas inert composition. A simple method to analyze optimal diffuser configuration is presented. The method assumes equilibrium across the Pd/Ag tubes and system flows are limited by diffuser vacuum pump speeds preceding or following the clean-up process. A plot of system feed as a function of inert feed gas composition for various diffuser configuration allows selection of a diffuser configuration for maximum throughput based on feed gas composition. (authors)
GraTeLPy: graph-theoretic linear stability analysis
2014-01-01
Background A biochemical mechanism with mass action kinetics can be represented as a directed bipartite graph (bipartite digraph), and modeled by a system of differential equations. If the differential equations (DE) model can give rise to some instability such as multistability or Turing instability, then the bipartite digraph contains a structure referred to as a critical fragment. In some cases the existence of a critical fragment indicates that the DE model can display oscillations for some parameter values. We have implemented a graph-theoretic method that identifies the critical fragments of the bipartite digraph of a biochemical mechanism. Results GraTeLPy lists all critical fragments of the bipartite digraph of a given biochemical mechanism, thus enabling a preliminary analysis on the potential of a biochemical mechanism for some instability based on its topological structure. The correctness of the implementation is supported by multiple examples. The code is implemented in Python, relies on open software, and is available under the GNU General Public License. Conclusions GraTeLPy can be used by researchers to test large biochemical mechanisms with mass action kinetics for their capacity for multistability, oscillations and Turing instability. PMID:24572152
A novel theoretical approach to the analysis of dendritic transients.
Agmon-Snir, H
1995-01-01
A novel theoretical framework for analyzing dendritic transients is introduced. This approach, called the method of moments, is an extension of Rall's cable theory for dendrites. It provides analytic investigation of voltage attenuation, signal delay, and synchronization problems in passive dendritic trees. In this method, the various moments of a transient signal are used to characterize the properties of the transient. The strength of the signal is measured by the time integral of the signal, its characteristic time is determined by its centroid ("center of gravity"), and the width of the signal is determined by a measure similar to the standard deviation in probability theory. Using these signal properties, the method of moments provides theorems, expressions, and efficient algorithms for analyzing the voltage response in arbitrary passive trees. The method yields new insights into spatiotemporal integration, coincidence detection mechanisms, and the properties of local interactions between synaptic inputs in dendritic trees. The method can also be used for matching dendritic neuron models to experimental data and for the analysis of synaptic inputs recorded experimentally. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 10 PMID:8580308
Experimental and theoretical analysis results for high temperature air combustion
Tanigawa, Tadashi; Morita, Mitsunobu
1998-07-01
With Japan's preparation of its Action program to prevent global warming in 1990 and the holding of the United National Conference on Environment and Development (the Earth Summit) in 1992 as a backdrop, reflecting the global effort to protect the environment, a high performance industrial furnace development project was launched in 1993 by the New Energy and Industrial Technology Development Organization (NEDO). This project focuses on the development of a combustion technology which uses air that is preheated to extremely high temperatures (above 1,000 C), heretofore considered impossible. Not only can this technology reduce carbon dioxide emission, thought to cause the greenhouse effect, by over 30%, but it can also reduce nitrogen oxide emission by nearly half. This new technology makes use of the recently-developed high-cycle regenerative heat exchanger, for preheating the furnace air supply. This exchanger preheats air to above 1,000 C, much higher than for conventional furnaces, and then this air is injected with fuel. R and D data have shown that CO{sub 2} and NO{sub x} emissions can be reduced markedly. However, the theoretical analysis is yet to be made, thereby hampering efforts to have this advanced technology become widely adopted. This project accumulated new data related to uniform temperature distribution, high energy heat transfer and low NO{sub x} as common characteristics of high temperature air combustion.
Theoretical and experimental analysis of a soluble enzyme membrane reactor.
Greco, G; Alfani, F; Iorio, G; Cantarella, M; Formisano, A; Gianfreda, L; Palescandolo, R; Scardi, V
1979-08-01
Recently enzyme immobilization techniques have been proposed that are mainly founded on the formation of an enzyme-gel layer onto the active surface of an ultrafiltration membrane within an unstirred ultrafiltration cell. If the membrane molecular-weight cutoff is less than the enzyme molecular weight and hence such as to completely prevent enzyme permeation (once the enzyme solution has been charged into the test cell and pressure applied to the system), a time progressive increase in enzyme concentration takes place at the upstream membrane surface that can eventually lead to gelation and hence to enzyme immobilization. However, depending on the total enzyme amount fed, the maximum enzyme concentration achieved in the unsteady state could be less than the gelation level. In this situation, no immobilization occurs and the enzyme still remains in the soluble form although it is practically confined within a limited region immediately upstream the membrane and at fairly high concentrations. In this paper, the experimental conditions that allow gelling to occur are discussed together with a theoretical analysis of the soluble enzyme membrane reactor which is obtained when no gelling takes place. Such a system could be usefully employed in performing kinetic analyses at high enzyme concentration levels that are still in the soluble form. PMID:454808
Theoretical analysis of magnetic field interactions with aortic blood flow
Kinouchi, Y.; Yamaguchi, H.; Tenforde, T.S.
1996-04-01
The flow of blood in the presence of a magnetic field gives rise to induced voltages in the major arteries of the central circulatory system. Under certain simplifying conditions, such as the assumption that the length of major arteries (e.g., the aorta) is infinite and that the vessel walls are not electrically conductive, the distribution of induced voltages and currents within these blood vessels can be calculated with reasonable precision. However, the propagation of magnetically induced voltages and currents from the aorta into neighboring tissue structures such as the sinuatrial node of the heart has not been previously determined by any experimental or theoretical technique. In the analysis presented in this paper, a solution of the complete Navier-Stokes equation was obtained by the finite element technique for blood flow through the ascending and descending aortic vessels in the presence of a uniform static magnetic field. Spatial distributions of the magnetically induced voltage and current were obtained for the aortic vessel and surrounding tissues under the assumption that the wall of the aorta is electrically conductive. Results are presented for the calculated values of magnetically induced voltages and current densities in the aorta and surrounding tissue structures, including the sinuatrial node, and for their field-strength dependence. In addition, an analysis is presented of magnetohydrodynamic interactions that lead to a small reduction of blood volume flow at high field levels above approximately 10 tesla (T). Quantitative results are presented on the offsetting effects of oppositely directed blood flows in the ascending and descending aortic segments, and a quantitative estimate is made of the effects of assuming an infinite vs. a finite length of the aortic vessel in calculating the magnetically induced voltage and current density distribution in tissue.
Pre/Post Data Analysis - Simple or Is It?
NASA Technical Reports Server (NTRS)
Feiveson, Al; Fiedler, James; Ploutz-Snyder, Robert
2011-01-01
This slide presentation reviews some of the problems of data analysis in analyzing pre and post data. Using as an example, ankle extensor strength (AES) experiments, to measure bone density loss during bed rest, the presentation discusses several questions: (1) How should we describe change? (2) Common analysis methods for comparing post to pre results. (3) What do we mean by "% change"? and (4) What are we testing when we compare % changes?
A method for suppression of pressure pulses in fluid-filled piping: Theoretical analysis
Shin, Y.W.; Wiedermann, A.H.
1988-06-01
A simple, nondestructive method to suppress pressure pulses in a fluid-filled piping is theoretically analyzed, and the result provides the basis needed for design and evaluation of a pressure-pulse suppression device based on the proposed theory. The method is based on forming of fluid jets in the event of a pressure surge such that the pulse height as well as the energy of the pulse are reduced. The result for pressure pulses in the range of practical interest shows that a substantial reduction can be attained in the pulse height with accompanied reduction of pulse energy remaining in the system. The analysis also reveals that a certain amount of trade-off exists in the design of the suppression device; a certain level of pulse energy remaining in the system must be accepted in order to limit the pulse height below a certain level and vice versa. 7 refs., 5 figs.
Development of Novel, Simple, Multianalyte Sensors For Remote Environmental Analysis
Asher, Sanfor A.
1999-06-01
We will develop simple, inexpensive new chemical sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of environmental pollutants such as cations of Pb, U, Pu, Sr, Hg, Cs, Co as well as other species. We will develop inexpensive chemical test strips which can be immersed in water to determine these analytes in the field. We will also develop arrays of these chemical sensing materials which will be attached to fiber optic bundles to be used as rugged multichannel optrodes to simultaneously monitor numerous analytes remotely in hostile environments. These sensing materials are based on the intelligent polymerized crystalline colloidal array (PCCA) technology we recently developed. This sensing motif utilizes a mesoscopically periodic array of colloidal particles polymerized into an acrylamide hydrogel. This array Bragg diffracts light in the visible spectral region due to the periodic array of colloidal particles. This material also contains chelating agents for the analytes of interest. When an analyte binds, its charge is immobilized within the acrylamide hydrogel. The resulting Donnan potential causes an osmotic pressure which swells the array proportional to the concentration of analyte bound. The diffracted wavelength shifts and the color changes. The change in the wavelength diffracted reports on the identity and concentration of the target analyte.
NASA Astrophysics Data System (ADS)
Sholtes, Joel; Werbylo, Kevin; Bledsoe, Brian
2014-10-01
Theoretical approaches to magnitude-frequency analysis (MFA) of sediment transport in channels couple continuous flow probability density functions (PDFs) with power law flow-sediment transport relations (rating curves) to produce closed-form equations relating MFA metrics such as the effective discharge, Qeff, and fraction of sediment transported by discharges greater than Qeff, f+, to statistical moments of the flow PDF and rating curve parameters. These approaches have proven useful in understanding the theoretical drivers behind the magnitude and frequency of sediment transport. However, some of their basic assumptions and findings may not apply to natural rivers and streams with more complex flow-sediment transport relationships or management and design scenarios, which have finite time horizons. We use simple numerical experiments to test the validity of theoretical MFA approaches in predicting the magnitude and frequency of sediment transport. Median values of Qeff and f+ generated from repeated, synthetic, finite flow series diverge from those produced with theoretical approaches using the same underlying flow PDF. The closed-form relation for f+ is a monotonically increasing function of flow variance. However, using finite flow series, we find that f+ increases with flow variance to a threshold that increases with flow record length. By introducing a sediment entrainment threshold, we present a physical mechanism for the observed diverging relationship between Qeff and flow variance in fine and coarse-bed channels. Our work shows that through complex and threshold-driven relationships sediment transport mode, channel morphology, flow variance, and flow record length all interact to influence estimates of what flow frequencies are most responsible for transporting sediment in alluvial channels.
ERIC Educational Resources Information Center
Norbury, John W.
2006-01-01
A set of examples is provided that illustrate the use of work as applied to simple machines. The ramp, pulley, lever and hydraulic press are common experiences in the life of a student, and their theoretical analysis therefore makes the abstract concept of work more real. The mechanical advantage of each of these systems is also discussed so that…
Simple hobby computer-based off-gas analysis system
Forrest, E.H.; Jansen, N.B.; Flickinger, M.C.; Tsao, G.T.
1981-02-01
An Apple II computer has been adapted to monitor fermentation offgas in laboratory and pilot scale fermentors. It can calculate oxygen uptake rates, carbon dioxide evolution rates, respiratory quotient as well as initiating recalibration procedures. In this report the computer-based off-gas analysis system is described.
A theoretical analysis of optimum consumer population and its control.
Jiang, Z; Mao, Z; Wang, H
1994-01-01
Material production is related to population consumption in every society. Consumption also constantly transforms materials, energy, and information. In this sense, consumption provides both impetus for material production and a self-adapting mechanism for population development and control. Population structure variables affecting economic production can be divided according to non-adults, working-age work force and the elderly, social status, and urban-rural structure. The consumptive structures among people of different social status reflect different needs for social and economic development. The theoretical calculation of the consumer population in the national economy demonstrates that the national income in a certain year of a given national economy equals consumption fund plus accumulation fund where consumption fund includes social consumption fund and residential consumption fund. Social consumption fund is spent mostly on public utilities, administrative management, national defense, education, public health and urban construction, as well as on environment management and disaster relief. The residential consumption fund can be divided into basic expenditure such as clothing, food, shelter and transportation, and self-improvement expenditure such as recreation, education, and travel. As a result of economic development, not only the percentage of the expenditure on food will decrease and the percentage of the expenditure on clothing, shelter, transportation, and other daily necessities will increase, but expenses on recreation and education also will grow. Residential consumption is divided into subsistence consumption (Type I consumption) and self-improvement (recreation and education) consumption (Type II consumption) in order to determine consumer population and the degree of urbanization and its impact upon social and economic development. A moderate consumer population model of urban and rural areas was established by using the urban and rural
A simple way to improved formulation of {FE}^2 analysis
NASA Astrophysics Data System (ADS)
Šolinc, Urša; Korelc, Jože
2015-11-01
A new formulation of two-scale {FE}^2 analysis introduces symmetric stretch tensor as strain measure on macro level instead of asymmetric deformation gradient to determine boundary conditions on embedded microstructure. This significantly reduces computational cost of boundary conditions related sensitivity analysis of microstructure and with it the evaluation of local macroscopic stress tensors and tangent matrices. Various {FE}^2 formulations with isogeometric and standard finite element microanalysis are tested for consistency, accuracy and numerical efficiency on numerical homogenisation examples. Objective performance comparison of different {FE}^2 formulations is enabled with automation of all procedures in symbolic code generation system AceGen. The results obtained in numerical examples show reduced computational cost of the new {FE}^2 formulation without loss of accuracy and comparable numerical efficiency of higher order isogeometric and standard {FE}^2 formulations.
Developmental Change in the Relation between Simple and Complex Spans: A Meta-Analysis
ERIC Educational Resources Information Center
Tillman, Carin M.
2011-01-01
In the present meta-analysis the effects of developmental level on the correlation between simple and complex span tasks were investigated. Simple span-complex span correlation coefficients presented in 52 independent samples (7,060 participants) were regressed on a variable representing mean age of sample (range: 4.96-22.80 years), using analyses…
Simple Sensitivity Analysis for Orion Guidance Navigation and Control
NASA Technical Reports Server (NTRS)
Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar
2013-01-01
The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch. We describe in this paper a sensitivity analysis tool ("Critical Factors Tool" or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.
Isogeometric analysis of free vibration of simple shaped elastic samples.
Kolman, Radek; Sorokin, Sergey; Bastl, Bohumír; Kopačka, Ján; Plešek, Jiří
2015-04-01
The paper is devoted to numerical solution of free vibration problems for elastic bodies of canonical shapes by means of a spline based finite element method (FEM), called Isogeometric Analysis (IGA). It has an advantage that the geometry is described exactly and the approximation of unknown quantities is smooth due to higher-order continuous shape functions. IGA exhibits very convenient convergence rates and small frequency errors for higher frequency spectrum. In this paper, the IGA strategy is used in computation of eigen-frequencies of a block and cylinder as benchmark tests. Results are compared with the standard FEM, the Rayleigh-Ritz method, and available experimental data. The main attention is paid to the comparison of convergence rate, accuracy, and time-consumption of IGA against FEM and also to show a spline order and parameterization effects. In addition, the potential of IGA in Resonant Ultrasound Spectroscopy measurements of elastic properties of general anisotropy solids is discussed. PMID:25920859
Theoretical analysis and experimental verification on optical rotational Doppler effect.
Zhou, Hailong; Fu, Dongzhi; Dong, Jianji; Zhang, Pei; Zhang, Xinliang
2016-05-01
We present a theoretical model to sufficiently investigate the optical rotational Doppler effect based on modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the difference of mode index between input and output orbital angular momentum (OAM) light, and linear to the rotating speed of spinning object as well. An experiment is carried out to verify the theoretical model. We explicitly suggest that the spatial spiral phase distribution of spinning object determines the frequency content. The theoretical model makes us better understand the physical processes of rotational Doppler effect, and thus has many related application fields, such as detection of rotating bodies, imaging of surface and measurement of OAM light. PMID:27137615
Theoretical analysis and experimental verification on optical rotational Doppler effect
NASA Astrophysics Data System (ADS)
Zhou, Hailong; Fu, Dongzhi; Dong, Jianji; Zhang, Pei; Zhang, Xinliang
2016-05-01
We present a theoretical model to sufficiently investigate the optical rotational Doppler effect based on modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the difference of mode index between input and output orbital angular momentum (OAM) light, and linear to the rotating speed of spinning object as well. An experiment is carried out to verify the theoretical model. We explicitly suggest that the spatial spiral phase distribution of spinning object determines the frequency content. The theoretical model makes us better understand the physical processes of rotational Doppler effect, and thus has many related application fields, such as detection of rotating bodies, imaging of surface and measurement of OAM light.
Towards theoretical analysis of long-range proton transfer kinetics in biomolecular pumps
König, P. H.; Ghosh, N.; Hoffmann, M.; Elstner, M.; Tajkhorshid, E.; Frauenheim, Th.; Cui, Q.
2008-01-01
Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, a number of technical developments were made in the framework of QM/MM simulations. A set of collective reaction co-ordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly non-linear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework. PMID:16405327
Simple and clean determination of tetracyclines by flow injection analysis
NASA Astrophysics Data System (ADS)
Rodríguez, Michael Pérez; Pezza, Helena Redigolo; Pezza, Leonardo
2016-01-01
An environmentally reliable analytical methodology was developed for direct quantification of tetracycline (TC) and oxytetracycline (OTC) using continuous flow injection analysis with spectrophotometric detection. The method is based on the diazo coupling reaction between the tetracyclines and diazotized sulfanilic acid in a basic medium, resulting in the formation of an intense orange azo compound that presents maximum absorption at 434 nm. Experimental design was used to optimize the analytical conditions. The proposed technique was validated over the concentration range of 1 to 40 μg mL- 1, and was successfully applied to samples of commercial veterinary pharmaceuticals. The detection (LOD) and quantification (LOQ) limits were 0.40 and 1.35 μg mL- 1, respectively. The samples were also analyzed by an HPLC method, and the results showed agreement with the proposed technique. The new flow injection method can be immediately used for quality control purposes in the pharmaceutical industry, facilitating monitoring in real time during the production processes of tetracycline formulations for veterinary use.
Relocation of the Aged: A Review and Theoretical Analysis
ERIC Educational Resources Information Center
Schulz, Richard; Brenner, Gail
1977-01-01
Literature on relocation of the aged is examined and findings are presented within a framework of three types of moves--institution to institution, home to institution, and home to home--with each type having a voluntary and involuntary component. A theoretical model is proposed to explain contradictory results reported. (Author)
Theoretical and Experimental Analysis of the Physics of Water Rockets
ERIC Educational Resources Information Center
Barrio-Perotti, R.; Blanco-Marigorta, E.; Fernandez-Francos, J.; Galdo-Vega, M.
2010-01-01
A simple rocket can be made using a plastic bottle filled with a volume of water and pressurized air. When opened, the air pressure pushes the water out of the bottle. This causes an increase in the bottle momentum so that it can be propelled to fairly long distances or heights. Water rockets are widely used as an educational activity, and several…
CMS Made Simple: A ROOT-less workflow for educating undergraduates about CMS data analysis
NASA Astrophysics Data System (ADS)
Muenkel, Jessica; Bellis, Matthew; CMS Collaboration
2015-04-01
Involving students in research is an important part of the undergraduate experience. By working on a problem where the answer is unknown, students apply what they learn in the classroom to a real-world challenge, which reinforce the more theoretical aspects of their courses. Many undergraduates are drawn to the idea of working on big particle physics experiments like CMS (Compact Muon Solenoid) at the Large Hadron Collider (LHC), but the threshold is high for them to contribute to an analysis. Those of us who perform research spend much of our time debugging scripts and C + + code, usually specific to that one experiment. If an undergraduate is not going on to grad school in particle physics, much of that work can be wasted on them. However, there are many general skills that students can learn by working on parts of a particle physics analysis (relativistic kinematics, statistics, coding, etc.), and so it is worth trying to lower the threshold to engage students. In this poster, we present a suite of datasets and tools, built around the Python programming language that simplify the workflow and allow a student to interact with CMS data immediately. While it is a staple of the particle physics community, we avoid using the ROOT toolkit, so as to stick to more broadly used tools that the students can take with them. These tools are being used to supplement the educational examples for the CERN Open Data Portal, a project to make LHC datasets available to the general public. The successes and limitations of CMS Made Simple will be discussed and links are provided to these tools.
Theoretical analysis of protein organization in lipid membranes.
Gil, T; Ipsen, J H; Mouritsen, O G; Sabra, M C; Sperotto, M M; Zuckermann, M J
1998-11-10
The fundamental physical principles of the lateral organization of trans-membrane proteins and peptides as well as peripheral membrane proteins and enzymes are considered from the point of view of the lipid-bilayer membrane, its structure, dynamics, and cooperative phenomena. Based on a variety of theoretical considerations and model calculations, the nature of lipid-protein interactions is considered both for a single protein and an assembly of proteins that can lead to aggregation and protein crystallization in the plane of the membrane. Phenomena discussed include lipid sorting and selectivity at protein surfaces, protein-lipid phase equilibria, lipid-mediated protein-protein interactions, wetting and capillary condensation as means of protein organization, mechanisms of two-dimensional protein crystallization, as well as non-equilibrium organization of active proteins in membranes. The theoretical findings are compared with a variety of experimental data. PMID:9804966
Remodeling of the bone material containing microcracks: A theoretical analysis
NASA Astrophysics Data System (ADS)
Ramtani, S.; Zidi, M.
1999-12-01
The question is, what happens when the bone loses its ability for load-driven adaptation, when damage is no longer repaired as it seems to be the case for bone loss associated with age, medication or disease? In this study, we tempt to show how damage can influence the remodeling process. A thermodynamic theoretical framework is therefore provided as a basis for a consistent formulation of bone remodeling involving a chemical reaction and mass transfer between two constituents in presence of microcracks.
Theoretical analysis of microtubule dynamics at all times.
Li, Xin; Kolomeisky, Anatoly B
2014-12-01
Microtubules are biopolymers consisting of tubulin dimer subunits. As a major component of cytoskeleton they are essential for supporting most important cellular processes such as cell division, signaling, intracellular transport and cell locomotion. The hydrolysis of guanosine triphosphate (GTP) molecules attached to each tubulin subunit supports the nonequilibrium nature of microtubule dynamics. One of the most spectacular properties of microtubules is their dynamic instability when their growth from continuous attachment of tubulin dimers stochastically alternates with periods of shrinking. Despite the critical importance of this process to all cellular activities, its mechanism remains not fully understood. We investigated theoretically microtubule dynamics at all times by analyzing explicitly temporal evolution of various length clusters of unhydrolyzed subunits. It is found that the dynamic behavior of microtubules depends strongly on initial conditions. Our theoretical findings provide a microscopic explanation for recent experiments which found that the frequency of catastrophes increases with the lifetime of microtubules. It is argued that most growing microtubule configurations cannot transit in one step into a shrinking state, leading to a complex overall temporal behavior. Theoretical calculations combined with Monte Carlo computer simulations are also directly compared with experimental observations, and good agreement is found. PMID:25390471
Thomas, John
2012-05-01
Systems Theoretic Process Analysis (STPA) is a powerful new hazard analysis method designed to go beyond traditional safety techniques - such as Fault Tree Analysis (FTA) - that overlook important causes of accidents like flawed requirements, dysfunctional component interactions, and software errors. While proving to be very effective on real systems, no formal structure has been defined for STPA and its application has been ad-hoc with no rigorous procedures or model-based design tools. This report defines a formal mathematical structure underlying STPA and describes a procedure for systematically performing an STPA analysis based on that structure. A method for using the results of the hazard analysis to generate formal safety-critical, model-based system and software requirements is also presented. Techniques to automate both the analysis and the requirements generation are introduced, as well as a method to detect conflicts between the safety and other functional model-based requirements during early development of the system.
A Measurement-Theoretic Analysis of the Fuzzy Logic Model of Perception.
ERIC Educational Resources Information Center
Crowther, Court S.; And Others
1995-01-01
The fuzzy logic model of perception (FLMP) is analyzed from a measurement-theoretic perspective. The choice rule of FLMP is shown to be equivalent to a version of the Rasch model. In fact, FLMP can be reparameterized as a simple two-category logit model. (SLD)
Role of temperature in the theoretical analysis of holmium pnictides
NASA Astrophysics Data System (ADS)
Bhardwaj, Purvee; Singh, Sadhna
2016-01-01
The high-pressure structural phase transition and associated properties of holmium pnictides (HoX; X = P, As, Sb and Bi) have been investigated in the present work. The Realistic Interaction Potential Approach (RIPA) including the effect of temperature has been applied. The occurrence of first order phase transition is evidenced from a sudden collapse in volume. These compounds transform from B1 to B2 structure under high pressure. The high temperature and pressure behaviour of elastic constants and bulk modulus are also reported. Our results are in general in good agreement with experimental and other theoretical results where available, and provide predictions where they are unavailable.
Analysis of NASA JP-4 fire tests data and development of a simple fire model
NASA Technical Reports Server (NTRS)
Raj, P.
1980-01-01
The temperature, velocity and species concentration data obtained during the NASA fire tests (3m, 7.5m and 15m diameter JP-4 fires) were analyzed. Utilizing the data analysis, a sample theoretical model was formulated to predict the temperature and velocity profiles in JP-4 fires. The theoretical model, which does not take into account the detailed chemistry of combustion, is capable of predicting the extent of necking of the fire near its base.
An Isotopic Dilution Experiment Using Liquid Scintillation: A Simple Two-System, Two-Phase Analysis.
ERIC Educational Resources Information Center
Moehs, Peter J.; Levine, Samuel
1982-01-01
A simple isotonic, dilution analysis whose principles apply to methods of more complex radioanalyses is described. Suitable for clinical and instrumental analysis chemistry students, experimental manipulations are kept to a minimum involving only aqueous extraction before counting. Background information, procedures, and results are discussed.…
Theoretical and software considerations for nonlinear dynamic analysis
NASA Technical Reports Server (NTRS)
Schmidt, R. J.; Dodds, R. H., Jr.
1983-01-01
In the finite element method for structural analysis, it is generally necessary to discretize the structural model into a very large number of elements to accurately evaluate displacements, strains, and stresses. As the complexity of the model increases, the number of degrees of freedom can easily exceed the capacity of present-day software system. Improvements of structural analysis software including more efficient use of existing hardware and improved structural modeling techniques are discussed. One modeling technique that is used successfully in static linear and nonlinear analysis is multilevel substructuring. This research extends the use of multilevel substructure modeling to include dynamic analysis and defines the requirements for a general purpose software system capable of efficient nonlinear dynamic analysis. The multilevel substructuring technique is presented, the analytical formulations and computational procedures for dynamic analysis and nonlinear mechanics are reviewed, and an approach to the design and implementation of a general purpose structural software system is presented.
Mass media and environmental issues: a theoretical analysis
Parlour, J.W.
1980-01-01
A critique of the weak empirical and theoretical foundations of commentaries on the mass media in the environmental literature argues that they stem from the incidental rather than fundamental concern for the social dimensions of environmental problems. The contributions of information theory, cybernetics, sociology, and political science to micro and macro theories of mass communications are reviewed. Information from empirical analyses of the mass media's portrayal of social issues, including the environment, is related to Hall's dominant ideology thesis of the mass media and the elitist-conflict model of society. It is argued that the media's portrayal of environmental issues is structured by dominant power-holding groups in society with the result that the media effectively function to maintain and reinforce the status quo to the advantage of these dominant groups. 78 references.
Theoretical analysis of crosstalk in near-infrared topography
NASA Astrophysics Data System (ADS)
Okada, E.; Okui, N.
2006-09-01
Crosstalk between changes in concentration of oxy-and deoxy-haemoglobin calculated by modified Lambert-Beer law in near-infrared topography is theoretically investigated. The change in intensity detected with source-detector pairs on the scalp caused by global or focal ahsorption change in the brain is predicted by Monte Carlo simulation. The topographic images of changes in oxy- and deoxy-haemoglobin are obtained from the changes in intensity detected with source-detector pairs on the scalp. The crosstalk depends on the relative position of the focal absorption change to source-detector pairs. The crosstalk is minimised when the focal absorption change is located below a measurement point that is the midpoint between a source and a detector.
Experimental and theoretical analysis of long waves transformation on a sloping beach
NASA Astrophysics Data System (ADS)
Szmidt, K.; Staroszczyk, R.; Hedzielski, B.
2009-09-01
Transformation of long water waves on a sloping beach has been investigated, both experimentally and theoretically. Experiments have been conducted in a 64 m long and 0.6 m wide laboratory flume at the Institute of Hydro-Engineering, Polish Academy of Sciences, in Gdansk, Poland. Plane monochromatic waves have been generated by a piston-type wave maker situated at one end of the flume, and the sloping beach has been modelled by an inclined rigid ramp, of the slope equal to either 10 or 15 per cent, placed at a distance of 12 m from the generator wall. The water wave parameters have been recorded by a set of gauges installed along the flume, both in its constant- and varying-depth parts. Additionally, the run-up of the wave has been measured by a special conductivity gauge mounted on the ramp along the wave propagation direction. The experiments have been carried out for a wide range of wave lengths and amplitudes, falling, however, into the long-wave regime. The theoretical analysis of the wave propagation phenomenon has been performed by solving the problem in Lagrangian coordinates, since this permits simple formulation of boundary conditions on the moving boundaries of the fluid domain. However, the price for it is a more complicated structure of equations describing the fluid motion, compared to more traditional approaches based on the Eulerian description. In order to simplify the analysis, the shallow water approximation is applied. An essential simplification, on which the theoretical formulation proposed in this work is based, is a kinematical assumption that fluid motion is "columnar"; that is, the vertical material lines of fluid particles remain vertical during the motion. Fundamental equations of the theoretical description of the problem have been derived by following the Hamilton principle. Owing to the above kinematical assumption on the fluid motion, all the integrands in the action integral are expressed in terms of only the fluid horizontal
Theoretical analysis of epigenetic cell memory by nucleosome modification.
Dodd, Ian B; Micheelsen, Mille A; Sneppen, Kim; Thon, Geneviève
2007-05-18
Chromosomal regions can adopt stable and heritable alternative states resulting in bistable gene expression without changes to the DNA sequence. Such epigenetic control is often associated with alternative covalent modifications of histones. The stability and heritability of the states are thought to involve positive feedback where modified nucleosomes recruit enzymes that similarly modify nearby nucleosomes. We developed a simplified stochastic model for dynamic nucleosome modification based on the silent mating-type region of the yeast Schizosaccharomyces pombe. We show that the mechanism can give strong bistability that is resistant both to high noise due to random gain or loss of nucleosome modifications and to random partitioning upon DNA replication. However, robust bistability required: (1) cooperativity, the activity of more than one modified nucleosome, in the modification reactions and (2) that nucleosomes occasionally stimulate modification beyond their neighbor nucleosomes, arguing against a simple continuous spreading of nucleosome modification. PMID:17512413
The capacity credit of wind power - A theoretical analysis
NASA Astrophysics Data System (ADS)
Haslett, J.; Diesendorf, M.
1981-01-01
The development of a probabilistic model of capacity credit for wind power in an electricity grid is discussed, and two concepts are studied: (1) the equivalent conventional capacity, and (2) the equivalent firm capacity. The model is developed by introducing a more realistic probability distribution of wind power output than the normal distribution, and by calculating the loss of load probability. The main findings indicate that the use of simple models of the variation of load, wind power and plant availability allows comparisons to be made between various alternative measures of capacity credit. For small penetrations of wind power into the grid, the capacity credit is approximately equal to the average wind power output, while for large penetrations the credit tends to a limit which is determined by the probability of zero wind power and the conventional plant characteristics.
Flavor symmetry based MSSM: Theoretical models and phenomenological analysis
NASA Astrophysics Data System (ADS)
Babu, K. S.; Gogoladze, Ilia; Raza, Shabbar; Shafi, Qaisar
2014-09-01
We present a class of supersymmetric models in which symmetry considerations alone dictate the form of the soft SUSY breaking Lagrangian. We develop a class of minimal models, denoted as sMSSM—for flavor symmetry-based minimal supersymmetric standard model—that respect a grand unified symmetry such as SO(10) and a non-Abelian flavor symmetry H which suppresses SUSY-induced flavor violation. Explicit examples are constructed with the flavor symmetry being gauged SU(2)H and SO(3)H with the three families transforming as 2+1 and 3 representations, respectively. A simple solution is found in the case of SU(2)H for suppressing the flavor violating D-terms based on an exchange symmetry. Explicit models based on SO(3)H without the D-term problem are developed. In addition, models based on discrete non-Abelian flavor groups are presented which are automatically free from D-term issues. The permutation group S3 with a 2+1 family assignment, as well as the tetrahedral group A4 with a 3 assignment are studied. In all cases, a simple solution to the SUSY CP problem is found, based on spontaneous CP violation leading to a complex quark mixing matrix. We develop the phenomenology of the resulting sMSSM, which is controlled by seven soft SUSY breaking parameters for both the 2+1 assignment and the 3 assignment of fermion families. These models are special cases of the phenomenological MSSM (pMSSM), but with symmetry restrictions. We discuss the parameter space of sMSSM compatible with LHC searches, B-physics constraints and dark matter relic abundance. Fine-tuning in these models is relatively mild, since all SUSY particles can have masses below about 3 TeV.
Theoretical analysis of single molecule spectroscopy lineshapes of conjugated polymers
NASA Astrophysics Data System (ADS)
Devi, Murali
Conjugated Polymers(CPs) exhibit a wide range of highly tunable optical properties. Quantitative and detailed understanding of the nature of excitons responsible for such a rich optical behavior has significant implications for better utilization of CPs for more efficient plastic solar cells and other novel optoelectronic devices. In general, samples of CPs are plagued with substantial inhomogeneous broadening due to various sources of disorder. Single molecule emission spectroscopy (SMES) offers a unique opportunity to investigate the energetics and dynamics of excitons and their interactions with phonon modes. The major subject of the present thesis is to analyze and understand room temperature SMES lineshapes for a particular CP, called poly(2,5-di-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (DEH-PPV). A minimal quantum mechanical model of a two-level system coupled to a Brownian oscillator bath is utilized. The main objective is to identify the set of model parameters best fitting a SMES lineshape for each of about 200 samples of DEH-PPV, from which new insight into the nature of exciton-bath coupling can be gained. This project also entails developing a reliable computational methodology for quantum mechanical modeling of spectral lineshapes in general. Well-known optimization techniques such as gradient descent, genetic algorithms, and heuristic searches have been tested, employing an L2 measure between theoretical and experimental lineshapes for guiding the optimization. However, all of these tend to result in theoretical lineshapes qualitatively different from experimental ones. This is attributed to the ruggedness of the parameter space and inadequateness of the L2 measure. On the other hand, when the dynamic reduction of the original parameter space to a 2-parameter space through feature searching and visualization of the search space paths using directed acyclic graphs(DAGs), the qualitative nature of the fitting improved significantly. For a more
[Analysis on the accuracy of simple selection method of Fengshi (GB 31)].
Li, Zhixing; Zhang, Haihua; Li, Suhe
2015-12-01
To explore the accuracy of simple selection method of Fengshi (GB 31). Through the study of the ancient and modern data,the analysis and integration of the acupuncture books,the comparison of the locations of Fengshi (GB 31) by doctors from all dynasties and the integration of modern anatomia, the modern simple selection method of Fengshi (GB 31) is definite, which is the same as the traditional way. It is believed that the simple selec tion method is in accord with the human-oriented thought of TCM. Treatment by acupoints should be based on the emerging nature and the individual difference of patients. Also, it is proposed that Fengshi (GB 31) should be located through the integration between the simple method and body surface anatomical mark. PMID:26964185
Genome mapping by random anchoring: A discrete theoretical analysis
NASA Astrophysics Data System (ADS)
Zhang, M. Q.; Marr, T. G.
1993-11-01
As a part of the international human genome project, large-scale genomic maps of human and other model organisms are being generated. More recently, mapping using various anchoring (as opposed to the traditional "fingerprinting") strategies have been proposed based largely on mathematical models. In all of the theoretical work dealing with anchoring, an anchor has been idealized as a point on a continuous, infinite-length genome. In general, it is not desirable to make these assumptions, since in practice they may be violated under a variety of actual biological situations. Here we analyze a discrete model that can be used to predict the expected progress made when mapping by random anchoring. By virtue of keeping all three length scales (genome length, clone length, and probe length) finite, our results for the random anchoring strategy are derived in full generality, which contain previous results as special cases and hence can have broad application for planning mapping experiments or assessing the accuracy of the continuum models. Finally, we pose a challenging nonrandom anchoring model corresponding to a more efficient mapping scheme.
A computational and theoretical analysis of falling frequency VLF emissions
NASA Astrophysics Data System (ADS)
Nunn, David; Omura, Yoshiharu
2012-08-01
Recently much progress has been made in the simulation and theoretical understanding of rising frequency triggered emissions and rising chorus. Both PIC and Vlasov VHS codes produce risers in the region downstream from the equator toward which the VLF waves are traveling. The VHS code only produces fallers or downward hooks with difficulty due to the coherent nature of wave particle interaction across the equator. With the VHS code we now confine the interaction region to be the region upstream from the equator, where inhomogeneity factor S is positive. This suppresses correlated wave particle interaction effects across the equator and the tendency of the code to trigger risers, and permits the formation of a proper falling tone generation region. The VHS code now easily and reproducibly triggers falling tones. The evolution of resonant particle current JE in space and time shows a generation point at -5224 km and the wavefield undergoes amplification of some 25 dB in traversing the nonlinear generation region. The current component parallel to wave magnetic field (JB) is positive, whereas it is negative for risers. The resonant particle trap shows an enhanced distribution function or `hill', whereas risers have a `hole'. According to recent theory (Omura et al., 2008, 2009) sweeping frequency is due primarily to the advective term. The nonlinear frequency shift term is now negative (˜-12 Hz) and the sweep rate of -800 Hz/s is approximately nonlinear frequency shift divided by TN, the transition time, of the order of a trapping time.
A game theoretic analysis of research data sharing
Wiersma, Paulien H.; van Weerden, Anne; Schieving, Feike
2015-01-01
While reusing research data has evident benefits for the scientific community as a whole, decisions to archive and share these data are primarily made by individual researchers. In this paper we analyse, within a game theoretical framework, how sharing and reuse of research data affect individuals who share or do not share their datasets. We construct a model in which there is a cost associated with sharing datasets whereas reusing such sets implies a benefit. In our calculations, conflicting interests appear for researchers. Individual researchers are always better off not sharing and omitting the sharing cost, at the same time both sharing and not sharing researchers are better off if (almost) all researchers share. Namely, the more researchers share, the more benefit can be gained by the reuse of those datasets. We simulated several policy measures to increase benefits for researchers sharing or reusing datasets. Results point out that, although policies should be able to increase the rate of sharing researchers, and increased discoverability and dataset quality could partly compensate for costs, a better measure would be to directly lower the cost for sharing, or even turn it into a (citation-) benefit. Making data available would in that case become the most profitable, and therefore stable, strategy. This means researchers would willingly make their datasets available, and arguably in the best possible way to enable reuse. PMID:26401453
Theoretical Analysis of Membrane Tension in Moving Cells
Schweitzer, Yonatan; Lieber, Arnon D.; Keren, Kinneret; Kozlov, Michael M.
2014-01-01
Lateral tension in cell plasma membranes plays an essential role in regulation of a number of membrane-related intracellular processes and cell motion. Understanding the physical factors generating the lateral tension and quantitative determination of the tension distribution along the cell membrane is an emerging topic of cell biophysics. Although experimental data are accumulating on membrane tension values in several cell types, the tension distribution along the membranes of moving cells remains largely unexplored. Here we suggest and analyze a theoretical model predicting the tension distribution along the membrane of a cell crawling on a flat substrate. We consider the tension to be generated by the force of actin network polymerization against the membrane at the cell leading edge. The three major factors determining the tension distribution are the membrane interaction with anchors connecting the actin network to the lipid bilayer, the membrane interaction with cell adhesions, and the force developing at the rear boundary due to the detachment of the remaining cell adhesion from the substrate in the course of cell crawling. Our model recovers the experimentally measured values of the tension in fish keratocytes and their dependence on the number of adhesions. The model predicts, quantitatively, the tension distribution between the leading and rear membrane edges as a function of the area fractions of the anchors and the adhesions. PMID:24411240
A Logical Analysis of Majorana's Papers on Theoretical Physics
NASA Astrophysics Data System (ADS)
Drago, A.; Esposito, S.
2006-05-01
We study two celebrated Majorana's papers through a method of investigation which relies upon the recently recognized distinction between classical logic and several kinds of non-classical logics, i.e. the failure of the double negation law. This law fails when a double negated sentence is not equivalent to the corresponding positive sentence, owing to the lack of scientific evidence of the latter one. All recognized double negated sentences inside the text of each paper are listed; the mere sequence of such sentences giving the logical thread of Majorana's arguing. This one is recognized to be of the Lagrangian kind, which mixes logical arguing and mathematical calculation; i.e. the author puts a fundamental problem which is solved by anticipating the mathematical hypothesis able to solve it, and then by drawing from this hypothesis the mathematical consequences in order to reach to desired result. Furthermore the rethoric of presentation used by Majorana results to be a juridical one, owing to his style of presenting the laws to which an ideal theoretical physicist has to conform his mind in order to solve the problem at issue.
Theoretical analysis of the light interaction with coagulated tissue
NASA Astrophysics Data System (ADS)
Jerath, Maya R.; Welch, Ashley J.
1992-08-01
During laser treatment, coagulation affects the optical properties of the tissue. In particular, the formation of a white lesion increases the scattering coefficient significantly. This change in the optical properties in turn affects the laser light distribution in the tissue. For example, what is the effect of the white lesion formed during photocoagulation of the retina upon reflection and fluence rate? This problem was simulated on a model medium consisting of a thin absorbing black paint layer covered with a 1 cm thick layer of fresh egg white. The egg white layer was subdivided into coagulated (white) and uncoagulated (clear) layers. The optical properties of coagulated and uncoagulated egg white were determined. These values were used to model light distribution in the medium for varying thicknesses of the coagulated egg white layer using the one dimensional Adding Doubling method. Our results show that the fluence reaching the paint layer increase until the coagulated layer reaches 100 micrometers , after which it falls off exponentially. It was also found that the total reflected light increases almost linearly at first as the coagulated layer thickens, and then begins to level off to an R(infinity ) at a coagulation thickness of 2 mm. Experimental measurements of reflection from a lesion with a CCD camera confirm the computed trends. These results provide a theoretical foundation for control of lesion thickness using reflectance images.
Theoretical analysis of the electronic properties of N3 derivatives.
Rekhis, Maamar; Labat, Frédéric; Ouamerali, Ourida; Ciofini, Ilaria; Adamo, Carlo
2007-12-20
The structural and electronic properties of nine derivatives of the N3 complex (cis-[Ru(4,4'-COOH-2,2'-bpy)2(NCS)2]) have been studied, using density functional theory (DFT) at a hybrid (PBE0) level, with the aim of finding a systematic way to improve their spectral absorption in the visible region for photoelectrochemical applications. To this end, by means of time dependent-DFT (TD-DFT) calculations, excited states were investigated in solution to simulate UV-vis spectra. Several effects have been taken into account: the effect of the presence and deprotonation of the carboxylic groups as well as the variation of the chalcogen within the NCX ligand (X=S, Se, or Te). Besides the excellent agreement between theoretical and available experimental data, with regards to potential future experimental applications of the investigated complexes, from the calculations, the cis-Ru(dcbpyH2)(NCSe)2 may appear as a good candidate to enhance the response of the N3 dye to light, even if only slightly. PMID:18004827
Accuracy Analysis of a Box-wing Theoretical SRP Model
NASA Astrophysics Data System (ADS)
Wang, Xiaoya; Hu, Xiaogong; Zhao, Qunhe; Guo, Rui
2016-07-01
For Beidou satellite navigation system (BDS) a high accuracy SRP model is necessary for high precise applications especially with Global BDS establishment in future. The BDS accuracy for broadcast ephemeris need be improved. So, a box-wing theoretical SRP model with fine structure and adding conical shadow factor of earth and moon were established. We verified this SRP model by the GPS Block IIF satellites. The calculation was done with the data of PRN 1, 24, 25, 27 satellites. The results show that the physical SRP model for POD and forecast for GPS IIF satellite has higher accuracy with respect to Bern empirical model. The 3D-RMS of orbit is about 20 centimeters. The POD accuracy for both models is similar but the prediction accuracy with the physical SRP model is more than doubled. We tested 1-day 3-day and 7-day orbit prediction. The longer is the prediction arc length, the more significant is the improvement. The orbit prediction accuracy with the physical SRP model for 1-day, 3-day and 7-day arc length are 0.4m, 2.0m, 10.0m respectively. But they are 0.9m, 5.5m and 30m with Bern empirical model respectively. We apply this means to the BDS and give out a SRP model for Beidou satellites. Then we test and verify the model with Beidou data of one month only for test. Initial results show the model is good but needs more data for verification and improvement. The orbit residual RMS is similar to that with our empirical force model which only estimate the force for along track, across track direction and y-bias. But the orbit overlap and SLR observation evaluation show some improvement. The remaining empirical force is reduced significantly for present Beidou constellation.
Theoretical performance analysis for CMOS based high resolution detectors.
Jain, Amit; Bednarek, Daniel R; Rudin, Stephen
2013-03-01
High resolution imaging capabilities are essential for accurately guiding successful endovascular interventional procedures. Present x-ray imaging detectors are not always adequate due to their inherent limitations. The newly-developed high-resolution micro-angiographic fluoroscope (MAF-CCD) detector has demonstrated excellent clinical image quality; however, further improvement in performance and physical design may be possible using CMOS sensors. We have thus calculated the theoretical performance of two proposed CMOS detectors which may be used as a successor to the MAF. The proposed detectors have a 300 μm thick HL-type CsI phosphor, a 50 μm-pixel CMOS sensor with and without a variable gain light image intensifier (LII), and are designated MAF-CMOS-LII and MAF-CMOS, respectively. For the performance evaluation, linear cascade modeling was used. The detector imaging chains were divided into individual stages characterized by one of the basic processes (quantum gain, binomial selection, stochastic and deterministic blurring, additive noise). Ranges of readout noise and exposure were used to calculate the detectors' MTF and DQE. The MAF-CMOS showed slightly better MTF than the MAF-CMOS-LII, but the MAF-CMOS-LII showed far better DQE, especially for lower exposures. The proposed detectors can have improved MTF and DQE compared with the present high resolution MAF detector. The performance of the MAF-CMOS is excellent for the angiography exposure range; however it is limited at fluoroscopic levels due to additive instrumentation noise. The MAF-CMOS-LII, having the advantage of the variable LII gain, can overcome the noise limitation and hence may perform exceptionally for the full range of required exposures; however, it is more complex and hence more expensive. PMID:24353390
Graph theoretical analysis of resting magnetoencephalographic functional connectivity networks
Rutter, Lindsay; Nadar, Sreenivasan R.; Holroyd, Tom; Carver, Frederick W.; Apud, Jose; Weinberger, Daniel R.; Coppola, Richard
2013-01-01
Complex networks have been observed to comprise small-world properties, believed to represent an optimal organization of local specialization and global integration of information processing at reduced wiring cost. Here, we applied magnitude squared coherence to resting magnetoencephalographic time series in reconstructed source space, acquired from controls and patients with schizophrenia, and generated frequency-dependent adjacency matrices modeling functional connectivity between virtual channels. After configuring undirected binary and weighted graphs, we found that all human networks demonstrated highly localized clustering and short characteristic path lengths. The most conservatively thresholded networks showed efficient wiring, with topographical distance between connected vertices amounting to one-third as observed in surrogate randomized topologies. Nodal degrees of the human networks conformed to a heavy-tailed exponentially truncated power-law, compatible with the existence of hubs, which included theta and alpha bilateral cerebellar tonsil, beta and gamma bilateral posterior cingulate, and bilateral thalamus across all frequencies. We conclude that all networks showed small-worldness, minimal physical connection distance, and skewed degree distributions characteristic of physically-embedded networks, and that these calculations derived from graph theoretical mathematics did not quantifiably distinguish between subject populations, independent of bandwidth. However, post-hoc measurements of edge computations at the scale of the individual vertex revealed trends of reduced gamma connectivity across the posterior medial parietal cortex in patients, an observation consistent with our prior resting activation study that found significant reduction of synthetic aperture magnetometry gamma power across similar regions. The basis of these small differences remains unclear. PMID:23874288
Analysis of Theoretical Metaphors with Illustrations from Family Systems Theory.
ERIC Educational Resources Information Center
Rosenblatt, Paul C.
Metaphoric analysis of family systems theory illustrates how metaphors and alternatives to those metaphors identify what a psychological theory has highlighted and obscured about the phenomena at its focus and how it has structured that phenomena. The most commonly used metaphors in family systems theory are the metaphors of system (system…
Theoretical Consideration of Forcible Rape: A Critical Analysis.
ERIC Educational Resources Information Center
Clagett, Arthur F.
1988-01-01
Examined differences in hypothetical apperceptive fantasies of committing forcible rape, which are held by male subjects, as compared with the hypothetical apperceptive fantasies of being forcibly raped, held by the female subjects. Developed a critical analysis of social and cross-cultural variables affecting rape. (Author/ABL)
An Optimality-Theoretic Analysis of Codas in Brazilian Portuguese
ERIC Educational Resources Information Center
Goodin-Mayeda, C. Elizabeth
2015-01-01
Brazilian Portuguese allows only /s, N, l, r/ syllable finally, and of these, only /s/ is realized faithfully (as well as /r/ for some speakers). In order to avoid unacceptable codas, dialects of Brazilian Portuguese employ such strategies as epenthesis, nasal absorption, debucalization, and gliding. The current analysis argues that codas in…
NASA Astrophysics Data System (ADS)
Norbury, John W.
2006-11-01
A set of examples is provided that illustrate the use of work as applied to simple machines. The ramp, pulley, lever and hydraulic press are common experiences in the life of a student, and their theoretical analysis therefore makes the abstract concept of work more real. The mechanical advantage of each of these systems is also discussed so that students can evaluate their usefulness as machines.
Theoretical analysis of wake-induced parachute collapse
Spahr, H.R.; Wolf, D.F.
1981-01-01
During recent drop tests of a prototype weapon system, the parachute collapsed soon after it became fully inflated. The magnitude and duration of the collapses were severe enough to degrade parachute performance drastically. A computer-assisted analysis is presented which models parachute inflation, forebody and parachute wake generation, and interaction between the wake and the inflating or collapsing parachute. Comparison of the analysis results with full-scale drop test results shows good agreement for two parachute sizes; both parachutes were tested with and without permanent reefing. Computer-generated graphics (black and white drawings, color slides, and color movies) show the forebody and inflating parachute, the wake, and the wake and parachute interaction.
Sequential Phenomena in Psychophysical Judgments: A Theoretical Analysis
NASA Technical Reports Server (NTRS)
Atkinson, R. C.; Carterette, E. C.; Kinchla, R. A.
1962-01-01
This paper deals with an analysis of psychophysical detection experiments designed to assess the limit of a human observer's level of sensitivity. A mathematical theory or the detection process is introduced that, in contrast to previous theories, provides an analysis of the sequential effects observed in psychophysical data. Two variations of the detection task are considered: information feedback and no-information feedback. In the feedback situation the subject is given information concerning the correctness of his responses, whereas in the no-feedback situation he is not. Data from a visual detection experiment with no-information feedback, and from an auditory detection experiment with information feedback are analyzed in terms of the theory. Finally, some general results are derived concerning the relationship between performance in the feedback situation and the no-feedback situation.
Isolating the Effects of Training Using Simple Regression Analysis: An Example of the Procedure.
ERIC Educational Resources Information Center
Waugh, C. Keith
This paper provides a case example of simple regression analysis, a forecasting procedure used to isolate the effects of training from an identified extraneous variable. This case example focuses on results of a three-day sales training program to improve bank loan officers' knowledge, skill-level, and attitude regarding solicitation and sale of…
A simple, bead-based assay for multiplex SNP analysis in wheat
Technology Transfer Automated Retrieval System (TEKTRAN)
Single nucleotide polymorphisms (SNPs) are the most abundant form of DNA polymorphism and are highly suitable for automated analysis. These polymorphisms can be used in plants as simple genetic markers for many breeding applications and are useful for cultivar identification, genetic mapping, trait ...
Global Study of the Simple Pendulum by the Homotopy Analysis Method
ERIC Educational Resources Information Center
Bel, A.; Reartes, W.; Torresi, A.
2012-01-01
Techniques are developed to find all periodic solutions in the simple pendulum by means of the homotopy analysis method (HAM). This involves the solution of the equations of motion in two different coordinate representations. Expressions are obtained for the cycles and periods of oscillations with a high degree of accuracy in the whole range of…
A Simple Card Trick: Teaching Qualitative Data Analysis Using a Deck of Playing Cards
ERIC Educational Resources Information Center
Waite, Duncan
2011-01-01
Yet today, despite recent welcome additions, relatively little is written about teaching qualitative research. Why is that? This article reports out a relatively simple, yet appealing, pedagogical move, a lesson the author uses to teach qualitative data analysis. Data sorting and categorization, the use of tacit and explicit theory in data…
Thermal analysis of a simple-cycle gas turbine in biogas power generation
Yomogida, D.E.; Thinh, Ngo Dinh
1995-09-01
This paper investigates the technical feasibility of utilizing small simple-cycle gas turbines (25 kW to 125 kW) for biogas power generation through thermal analysis. A computer code, GTPower, was developed to evaluate the performance of small simple-cycle gas turbines specifically for biogas combustion. The 125 KW Solar Gas Turbine (Tital series) has been selected as the base case gas turbine for biogas combustion. After its design parameters and typical operating conditions were entered into GTPower for analysis, GTPower outputted expected values for the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work profiles for various operating conditions encountered in biogas combustion. These results will assist future research projects in determining the type of combustion device most suitable for biogas power generation.
A theoretical analysis of time-dependent fragment momenta in indirect photofragmentation.
Henriksen, Niels E
2010-06-21
We study theoretically diatomic molecules which are prepared in a superposition of quasibound resonance states by a femtosecond laser pulse. An analytical (Landau-Zener-like) result is derived for the momentum distribution of the atomic fragments in the asymptotic force-free region after a single passage of a curve crossing. Furthermore, at later times, simple analytical expressions show how the emerging structures in the momentum distribution are related to the energies of the resonance states. PMID:20572709
Graph theoretical analysis of complex networks in the brain
Stam, Cornelis J; Reijneveld, Jaap C
2007-01-01
Since the discovery of small-world and scale-free networks the study of complex systems from a network perspective has taken an enormous flight. In recent years many important properties of complex networks have been delineated. In particular, significant progress has been made in understanding the relationship between the structural properties of networks and the nature of dynamics taking place on these networks. For instance, the 'synchronizability' of complex networks of coupled oscillators can be determined by graph spectral analysis. These developments in the theory of complex networks have inspired new applications in the field of neuroscience. Graph analysis has been used in the study of models of neural networks, anatomical connectivity, and functional connectivity based upon fMRI, EEG and MEG. These studies suggest that the human brain can be modelled as a complex network, and may have a small-world structure both at the level of anatomical as well as functional connectivity. This small-world structure is hypothesized to reflect an optimal situation associated with rapid synchronization and information transfer, minimal wiring costs, as well as a balance between local processing and global integration. The topological structure of functional networks is probably restrained by genetic and anatomical factors, but can be modified during tasks. There is also increasing evidence that various types of brain disease such as Alzheimer's disease, schizophrenia, brain tumours and epilepsy may be associated with deviations of the functional network topology from the optimal small-world pattern. PMID:17908336
A Theoretical Analysis of Thermal Radiation from Neutron Stars
NASA Technical Reports Server (NTRS)
Applegate, James H.
1993-01-01
As soon as it was realized that the direct URCA process is allowed by many modern nuclear equation of state, an analysis of its effect on the cooling of neutron stars was undertaken. A primary study showed that the occurrence of the direct URCA process makes the surface temperature of a neutron star suddenly drop by almost an order of magnitude when the cold wave from the core reaches the surface when the star is a few years old. The results of this study are published in Page and Applegate. As a work in progress, we are presently extending the above work. Improved expressions for the effect of nucleon pairing on the neutrino emissivity and specific heat are now available, and we have incorporated them in a recalculation of rate of the direct URCA process.
Theoretical analysis of the density within an orbiting molecular shield
NASA Technical Reports Server (NTRS)
Hueser, J. E.; Brock, F. J.
1976-01-01
An analytical model based on the kinetic theory of a drifting Maxwellian gas is used to determine the nonequilibrium molecular density distribution within a hemispherical shell open aft with its axis parallel to its velocity. Separate numerical results are presented for the primary and secondary density distribution components due to the drifting Maxwellian gas for speed ratios between 2.5 and 10. An analysis is also made of the density component due to gas desorbed from the wall of the hemisphere, and numerical results are presented for the density distribution. It is shown that the adsorption process may be completely ignored. The results are applicable to orbital trajectories in any planet-atmosphere system and interplanetary transfer trajectories. Application to the earth's atmosphere is mentioned briefly.
Theoretical analysis of a cell's oscillations in an acoustic field
NASA Astrophysics Data System (ADS)
Allen, John S.; Zinin, Pavel
2005-09-01
The analysis and deformation of an individual cell in a high-frequency acoustic field is of fundamental interest for a variety of applications such as ultrasound cell separation and drug delivery. The oscillations of biological cells in a sound field are investigated using a shell model for the cell following an approach developed previously [Zinin, Ultrasonics, 30, 26-34 (1992)]. The model accounts for the three components which comprise the cell's motion: the internal fluid (cytoplasma), the cell membrane, and the surrounding fluid. The cell membrane whose thickness is small compared to the cell radius can be approximated as a thin elastic shell. The elastic properties of this shell together with the viscosities of the internal and external fluids determine the oscillations of the cell. The dipole oscillations of the cell depend on the surface area modulus and the maximum frequency for the relative change in cell area can be determined. Moreover, the higher order oscillations starting with the quadrupole oscillations are governed by the shell's shear modulus. Induced stresses in bacteria cell membranes in the vicinity of an oscillating bubble are investigated and cell rupture with respect to these stresses is analyzed.
Theoretical and numerical analysis of the corneal air puff test
NASA Astrophysics Data System (ADS)
Simonini, Irene; Angelillo, Maurizio; Pandolfi, Anna
2016-08-01
Ocular analyzers are used in the current clinical practice to estimate, by means of a rapid air jet, the intraocular pressure and other eye's parameters. In this study, we model the biomechanical response of the human cornea to the dynamic test with two approaches. In the first approach, the corneal system undergoing the air puff test is regarded as a harmonic oscillator. In the second approach, we use patient-specific geometries and the finite element method to simulate the dynamic test on surgically treated corneas. In spite of the different levels of approximation, the qualitative response of the two models is very similar, and the most meaningful results of both models are not significantly affected by the inclusion of viscosity of the corneal material in the dynamic analysis. Finite element calculations reproduce the observed snap-through of the corneal shell, including two applanate configurations, and compare well with in vivo images provided by ocular analyzers, suggesting that the mechanical response of the cornea to the air puff test is actually driven only by the elasticity of the stromal tissue. These observations agree with the dynamic characteristics of the test, since the frequency of the air puff impulse is several orders of magnitude larger than the reciprocal of any reasonable relaxation time for the material, downplaying the role of viscosity during the fast snap-through phase.
Theoretical analysis of droplet transition from Cassie to Wenzel state
NASA Astrophysics Data System (ADS)
Liu, Tian-Qing; Yan-Jie, Li; Xiang-Qin, Li; Wei, Sun
2015-11-01
Whether droplets transit from the Cassie to the Wenzel state (C-W) on a textured surface is the touchstone that the superhydrophobicity of the surface is still maintained. However, the C-W transition mechanism, especially the spontaneous transition of small droplets, is still not very clear to date. The interface free energy gradient of a small droplet is firstly proposed and derived as the driving force for its C-W evolution in this study based on the energy and gradient analysis. Then the physical and mathematical model of the C-W transition is found after the C-W driving force or transition pressure, the resistance, and the parameters of the meniscus beneath the droplet are formulated. The results show that the micro/nano structural parameters significantly affect the C-W driving force and resistance. The smaller the pillar diameter and pitch, the minor the C-W transition pressure, and the larger the resistance. Consequently, the C-W transition is difficult to be completed for the droplets on nano-textured surfaces. Meanwhile if the posts are too short, the front of the curved liquid-air interface below the droplet will touch the structural substrate easily even though the three phase contact line (TPCL) has not depinned. When the posts are high enough, the TPCL beneath the drop must move firstly before the meniscus can reach the substrate. As a result, the droplet on a textured surface with short pillars is easy to complete its C-W evolution. On the other hand, the smaller the droplet, the easier the C-W shift, since the transition pressure becomes larger, which well explains why an evaporating drop will collapse spontaneously from composite to Wenzel state. Besides, both intrinsic and advancing contact angles affect the C-W transition as well. The greater the two angles, the harder the C-W transition. In the end, the C-W transition parameters and the critical conditions measured in literatures are calculated and compared, and the calculations accord well with
Quantitative Analysis of the Nanopore Translocation Dynamics of Simple Structured Polynucleotides
Schink, Severin; Renner, Stephan; Alim, Karen; Arnaut, Vera; Simmel, Friedrich C.; Gerland, Ulrich
2012-01-01
Nanopore translocation experiments are increasingly applied to probe the secondary structures of RNA and DNA molecules. Here, we report two vital steps toward establishing nanopore translocation as a tool for the systematic and quantitative analysis of polynucleotide folding: 1), Using α-hemolysin pores and a diverse set of different DNA hairpins, we demonstrate that backward nanopore force spectroscopy is particularly well suited for quantitative analysis. In contrast to forward translocation from the vestibule side of the pore, backward translocation times do not appear to be significantly affected by pore-DNA interactions. 2), We develop and verify experimentally a versatile mesoscopic theoretical framework for the quantitative analysis of translocation experiments with structured polynucleotides. The underlying model is based on sequence-dependent free energy landscapes constructed using the known thermodynamic parameters for polynucleotide basepairing. This approach limits the adjustable parameters to a small set of sequence-independent parameters. After parameter calibration, the theoretical model predicts the translocation dynamics of new sequences. These predictions can be leveraged to generate a baseline expectation even for more complicated structures where the assumptions underlying the one-dimensional free energy landscape may no longer be satisfied. Taken together, backward translocation through α-hemolysin pores combined with mesoscopic theoretical modeling is a promising approach for label-free single-molecule analysis of DNA and RNA folding. PMID:22225801
de Haan, Jeroen; Schep, Niels; Tuinebreijer, Wim; den Hartog, Dennis
2010-01-01
Objective: The primary objective of this review of the literature with quantitative analysis of individual patient data was to identify the results of available treatments for complex elbow dislocations and unstable simple elbow dislocations. The secondary objective was to compare the results of patients with complex elbow dislocations and unstable elbow joints after repositioning of simple elbow dislocations, which were treated with an external fixator versus without an external fixator. Search Strategy: Electronic databases MEDLINE, EMBASE, LILACS, and the Cochrane Central Register of Controlled Trials. Selection Criteria: Studies were eligible for inclusion if they included individual patient data of patients with complex elbow dislocations and unstable simple elbow dislocations. Data Analysis: The different outcome measures (MEPI, Broberg and Morrey, ASES, DASH, ROM, arthritis grading) are presented with mean and confidence intervals. Main Results: The outcome measures show an acceptable range of motion with good functional scores of the different questionnaires and a low mean arthritis score. Thus, treatment of complex elbow dislocations with ORIF led to a moderate to good result. Treatment of unstable simple elbow dislocations with repair of the collateral ligaments with or without the combination of an external fixator is also a good option. The physician-rated (MEPI, Broberg and Morrey), patient-rated (DASH) and physician- and patient-rated (ASES) questionnaires showed good intercorrelations. Arthritis classification by x-ray is only fairly correlated with range of motion. Elbow dislocations are mainly on the non-dominant side. PMID:20361035
ERIC Educational Resources Information Center
Zhu, Wenzhong; Liu, Dan
2014-01-01
Based on a review of the literature on ESP and needs analysis, this paper is intended to offer some theoretical supports and inspirations for BE instructors to develop BE curricula for business contexts. It discusses how the theory of need analysis can be used in Business English curriculum design, and proposes some principles of BE curriculum…
Chiba, Akira; Fukao, Tadashi
1995-12-31
In this paper, a mathematical analysis based on a simple model is carried out. The operating characteristics of switched reluctance motors fed by square waveform voltage are analyzed. Inductance variations with respect to the rotor rotational position is approximated with only a sinusoidal function and a constant. Square waveform voltage is approximated by a fundamental component only. Based on this simple representation, it is possible to analyze operating characteristics mathematically in normalized planes and to derive a general control method. It is found that there exists a particular voltage phase angle which realizes the maximum output per current. It was also found that the maximum output per voltage can be achieved at the another particular voltage phase angle. These characteristics are found to be very similar to those of synchronous reluctance motors. As a result of the analysis, an efficient operating method is proposed. These results are confirmed by a 6,000 r/min., 2kW prototype machine.
Global analysis of a simple parasite-host model with homoclinic orbits.
Li, Jianquan; Xiao, Yanni; Yang, Yali
2012-10-01
In this paper, a simple parasite-host model proposed by Ebert et al.(2000) is reconsidered. The basic epidemiological reproduction number of parasite infection (R0) and the basic demographic reproduction number of infected hosts (R1) are given. The global dynamics of the model is completely investigated, and the existence of heteroclinic and homoclinic orbits is theoretically proved, which implies that the outbreak of parasite infection may happen. The thresholds determining the host extinction in the presence of parasite infection and variation in the equilibrium level of the infected hosts with R0 are found. The effects of R0 and R1 on dynamics of the model are considered and we show that the equilibrium level of the infected host may not be monotone with respect to R0. In particular, it is found that full loss of fecundity of infected hosts may lead to appearance of the singular case. PMID:23311421
Analysis of dietary interventions. A simple payoff matrix for display of comparative dietary trials
Feinman, Richard D; Fine, Eugene J; Volek, Jeff S
2008-01-01
Objective To provide a simple method for presentation of data in comparative dietary trials. Methods Individual data from each diet are ranked and all possible paired comparisons are made and displayed in a pay-off matrix which can be color-coded according to the magnitude of the differences between the two diets. Probability of outcome can be calculated from the fraction of matrix elements corresponding to specified conditions. The method has the advantage of emphasizing differences and providing the maximum amount of information. Results The method was tested with values from the literature and allows intuitive sense of the comparative effectiveness of the two diets. In a test case in which a cross-over study had been performed the matrix derived from theoretical paired comparisons (treating the data as two parallel studies) was consistent with the results from the actual pairing in the cross-over. Conclusion The matrix method is a simple way of providing access to the differences between dietary trials. It exaggerates differences but can be used in combination with group statistics that, conversely, provide reliability at the expense of detailed information. PMID:18759982
Reibnegger, G; Fuchs, D; Hausen, A; Werner, E R; Werner-Felmayer, G; Dierich, M P; Wachter, H
1989-01-01
A mathematical analysis is presented for several simple dynamical systems that might be considered as crude descriptions for the situation when an immune system retrovirus, immune cells, and normal autonomously replicating pathogens interact. By stability analysis of the steady-state solutions, the destabilizing effect of the immune system retrovirus is described. The qualitative behavior of the solutions depending on the system parameters is analyzed in terms of trajectories moving in a phase space in which the axes are defined by the population numbers of the interacting biological entities. PMID:2522657
Liao, Jian-Qiong; Song, Xiang; Chen, Ying; Liang, Li-Chang; Wang, Sheng-Xu
2014-06-01
The clinical therapeutic effect of acupoint catgut-embedding for simple obesity was systemically analyzed to provide reference and assistance for its clinical treatment and research. By searching in the CBM, CNKI, VIP, Wanfang, Pubmed, Springer and Medline databases, clinical randomized controlled trials (RCT) of acupoint catgut-embedding for simple obesity published from Jan, 2009 to July, 2013 were collected while Revman 5. 2 software was applied to perform the Meta-analysis. Totally 19 articles were acquired with 1 658 cases involved. The effective rate was selected as primary outcome measure in 19 articles. The Meta-analysis was performed among homogeneous researches. The results indicated that compared with other therapies, pooled OR of acupoint catgut-embedding was 2.45 with 95% CI [1.81, 3.32]; in the test for overall effect, Z = 5.81, implying the efficacy difference of two therapies was significant in the treatment of simple obesity (P < 0.01). In subgroups analysis, in the event of treatment session with more than 3 months, compared with other therapies, pooled OR of acupoint catgut-embedding was 2.61 with 95% CI [1.53, 4.46]; in test for overall effect, Z = 3.51, implying the efficacy difference of two therapies was significant in the treatment of simple obesity (P < 0.01); in the event of treatment session with less than 3 months, compared with other therapies, pooled OR of acupoint catgut-embedding was 2.38 with 95% CI [1.65, 3.44]; in test for overall effect, Z = 4.46, implying in the treatment of simple obesity the efficacy difference of two therapies was significant (P < 0.01). Compared with electroacupuncture, OR of acupoint catgut-embedding was 1.79, 95% CI [1.08, 2.95] (P = 0.02). Compared with acupuncture, OR of acupoint catgut-embedding was 1.89, 95% CI [1.16, 3.09] (P = 0.01), which explained that compared with electroacupuncture and acupuncture, the efficacy of acupoint catgut-embedding was significantly different. In a word, the clinical
NASA Astrophysics Data System (ADS)
Thullner, Martin; Jin, Shuang; Stadler, Susanne
2016-04-01
Stable isotope methods have been establish as powerful tools for the analysis of reactive transformation in the subsurface with applications ranging from the field of contaminant hydrology to biogeochemical cycling. While the link between single transformations based on stable isotope signatures and their changes is commonly well understood and allows for qualitative and - in case certain requirements are met - also quantitative analysis, the interpretation of sequential reactive transformations, e.g. decay chains, is more complicated. In the latter case isotope signature changes of individual reactive compounds are affected by more than one transformation which challenges the interpretation of these changes. In recent years, some methods have been proposed (e.g. isotope mass balance approaches) which allow at least for a qualitative or semi-quantitative estimation of sequential reactive transformation processes. However, a systematic assessment of the validity of these estimation methods is missing so far and the accuracy of these methods - in general and for specific conditions encountered in the field - is not fully validated. In this presentation we use a combination of mathematical analyses and numerical modeling to test the validity of the proposed estimation methods and to determine the limits of their applicability. Results recommend modifications of existing theoretical estimation approaches and identify sorption processes as potential limitation of their applicability.
Lee, S. M.; Dos Santos, A.
2012-07-01
The theoretical analysis of the subcritical experiments performed at the IPEN/MB-01 reactor employing the coupled NJOY/AMPX-II/TORT systems was successfully accomplished. All the analysis was performed employing ENDF/B-VII.0. The theoretical approach follows all the steps of the subcritical model of Gandini and Salvatores. The theory/experiment comparison reveals that the calculated subcritical reactivity is in a very good agreement to the experimental values. The subcritical index ({xi}) shows some discrepancies although in this particular case some work still have to be made to model in a better way the neutron source present in the experiments. (authors)
Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.
2015-02-17
We demonstrate that a non-perturbative framework for the treatment of the excitations of single walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. Asmore » a result, we test this theory explicitly on the data reported in [NanoLetters 5, 2314 (2005)] and [Phys. Rev. B 82, 195424 (2010)] and so demonstrate the method works over a wide range of reported excitonic spectra.« less
NASA Astrophysics Data System (ADS)
Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.
2015-02-01
We demonstrate that a nonperturbative framework for the treatment of the excitations of single-walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. We test this theory explicitly on the data reported by Dukovic et al. [Nano Lett. 5, 2314 (2005), 10.1021/nl0518122] and Sfeir et al. [Phys. Rev. B 82, 195424 (2010), 10.1103/PhysRevB.82.195424] and so demonstrate the method works over a wide range of reported excitonic spectra.
Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.
2015-02-17
We demonstrate that a non-perturbative framework for the treatment of the excitations of single walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. As a result, we test this theory explicitly on the data reported in [NanoLetters 5, 2314 (2005)] and [Phys. Rev. B 82, 195424 (2010)] and so demonstrate the method works over a wide range of reported excitonic spectra.
Cottis, R.A.; Turgoose, S.; Mendoza-Flores, J.
1996-12-31
The theoretical basis of electrochemical noise resistance measurements in the presence of significant solution resistance is examined with a simple linear circuit model. A shot noise model of the noise generation process is assumed to develop the dependence of electrochemical potential and current noise on corrosion rate, although the conclusions in respect to electrochemical noise resistance do not depend on this. It is concluded that the electrochemical noise resistance method measures essentially the same resistance as is measured by a conventional linear polarization resistance measurement, although it is found to be capable of making measurements in higher resistance systems.
The Syllable Contact Constraint in Korean: An Optimality-Theoretic Analysis.
ERIC Educational Resources Information Center
Davis, Stuart; Shin, Seung-Hoon
1999-01-01
Shows that the high-ranking syllable contact constraint is the driving force behind the well-known nasalization and lateralization phenomena in Korean. Develops an optimality-theoretic analysis of Korean nasalization and lateralization in which SyllCon is an undominated constraint. (Author/VWL)
A Simple Cost-Effective Framework for iPhone Forensic Analysis
NASA Astrophysics Data System (ADS)
Husain, Mohammad Iftekhar; Baggili, Ibrahim; Sridhar, Ramalingam
Apple iPhone has made significant impact on the society both as a handheld computing device and as a cellular phone. Due to the unique hardware system as well as storage structure, iPhone has already attracted the forensic community in digital investigation of the device. Currently available commercial products and methodologies for iPhone forensics are somewhat expensive, complex and often require additional hardware for analysis. Some products are not robust and often fail to extract optimal evidence without modifying the iPhone firmware which makes the analysis questionable in legal platforms. In this paper, we present a simple and inexpensive framework (iFF) for iPhone forensic analysis. Through experimental results using real device, we have shown the effectiveness of this framework in extracting digital evidence from an iPhone.
NASA Technical Reports Server (NTRS)
Levy, G.; Brown, R. A.
1986-01-01
A simple economical objective analysis scheme is devised and tested on real scatterometer data. It is designed to treat dense data such as those of the Seasat A Satellite Scatterometer (SASS) for individual or multiple passes, and preserves subsynoptic scale features. Errors are evaluated with the aid of sampling ('bootstrap') statistical methods. In addition, sensitivity tests have been performed which establish qualitative confidence in calculated fields of divergence and vorticity. The SASS wind algorithm could be improved; however, the data at this point are limited by instrument errors rather than analysis errors. The analysis error is typically negligible in comparison with the instrument error, but amounts to 30 percent of the instrument error in areas of strong wind shear. The scheme is very economical, and thus suitable for large volumes of dense data such as SASS data.
Security Analysis of Selected AMI Failure Scenarios Using Agent Based Game Theoretic Simulation
Abercrombie, Robert K; Schlicher, Bob G; Sheldon, Frederick T
2014-01-01
Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. We concentrated our analysis on the Advanced Metering Infrastructure (AMI) functional domain which the National Electric Sector Cyber security Organization Resource (NESCOR) working group has currently documented 29 failure scenarios. The strategy for the game was developed by analyzing five electric sector representative failure scenarios contained in the AMI functional domain. From these five selected scenarios, we characterize them into three specific threat categories affecting confidentiality, integrity and availability (CIA). The analysis using our ABGT simulation demonstrates how to model the AMI functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the AMI network with respect to CIA.
In- silico exploration of thirty alphavirus genomes for analysis of the simple sequence repeats
Alam, Chaudhary Mashhood; Singh, Avadhesh Kumar; Sharfuddin, Choudhary; Ali, Safdar
2014-01-01
The compilation of simple sequence repeats (SSRs) in viruses and its analysis with reference to incidence, distribution and variation would be instrumental in understanding the functional and evolutionary aspects of repeat sequences. Present study encompasses the analysis of SSRs across 30 species of alphaviruses. The full length genome sequences, assessed from NCBI were used for extraction and analysis of repeat sequences using IMEx software. The repeats of different motif sizes (mono- to penta-nucleotide) observed therein exhibited variable incidence across the species. Expectedly, mononucleotide A/T was the most prevalent followed by dinucleotide AG/GA and trinucleotide AAG/GAA in these genomes. The conversion of SSRs to imperfect microsatellite or compound microsatellite (cSSR) is low. cSSR, primarily constituted by variant motifs accounted for up to 12.5% of the SSRs. Interestingly, seven species lacked cSSR in their genomes. However, the SSR and cSSR are predominantly localized to the coding region ORFs for non structural protein and structural proteins. The relative frequencies of different classes of simple and compound microsatellites within and across genomes have been highlighted. PMID:25606453
Belisle, A.A.; Swineford, D.M.
1988-01-01
A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.
JaeHwa Koh; DuckJoo Yoon; Chang H. Oh
2010-07-01
An electrolyzer model for the analysis of a hydrogen-production system using a solid oxide electrolysis cell (SOEC) has been developed, and the effects for principal parameters have been estimated by sensitivity studies based on the developed model. The main parameters considered are current density, area specific resistance, temperature, pressure, and molar fraction and flow rates in the inlet and outlet. Finally, a simple model for a high-temperature hydrogen-production system using the solid oxide electrolysis cell integrated with very high temperature reactors is estimated.
[Efficacy analysis and theoretical study on Chinese herbal properties of Açaí (Euterpe oleracea)].
Zhang, Jian-jun; Chen, Shao-hong; Zhu, Ying-li; Wang, Chun; Wang, Jing-xia; Wang, Lin-yuan; Gao, Xue-min
2015-06-01
Açaí (Euterpe oleracea) emerged as a source of herb has a long history in South America, which was approved by the Ministry of Health used in China and it has been introduced planting in Guangdong and Taiwan. This article summarized applied history of Açaí and its present status in China. Did theoretical study on the Chinese herbal properties of Açaí based on the Chinese traditional philosophical culture to analysis the function and symptom preliminary, combining with used for medical recordation, chemical component, biological activity. It is aiming at establishing the theoretical foundation for the application under the guidance of TCM theory. PMID:26552192
ERIC Educational Resources Information Center
St. Andre, Ralph E.
Simple machines have become a lost point of study in elementary schools as teachers continue to have more material to cover. This manual provides hands-on, cooperative learning activities for grades three through eight concerning the six simple machines: wheel and axle, inclined plane, screw, pulley, wedge, and lever. Most activities can be…
Using Simple Statistical Analysis of Historical Data to Understand Wind Ramp Events
Kamath, C
2010-01-29
As renewable resources start providing an increasingly larger percentage of our energy needs, we need to improve our understanding of these intermittent resources so we can manage them better. In the case of wind resources, large unscheduled changes in the energy output, called ramp events, make it challenging to keep the load and the generation balanced. In this report, we show that simple statistical analysis of the historical data on wind energy generation can provide insights into these ramp events. In particular, this analysis can help answer questions such as the time period during the day when these events are likely to occur, the relative severity of positive and negative ramps, and the frequency of their occurrence. As there are several ways in which ramp events can be defined and counted, we also conduct a detailed study comparing different options. Our results indicate that the statistics are relatively insensitive to these choices, but depend on utility-specific factors, such as the magnitude of the ramp and the time interval over which this change occurs. These factors reflect the challenges faced by schedulers and operators in keeping the load and generation balanced and can change over the years. We conduct our analysis using data from wind farms in the Tehachapi Pass region in Southern California and the Columbia Basin region in Northern Oregon; while the results for other regions are likely to be different, the report describes the benefits of conducting simple statistical analysis on wind generation data and the insights that can be gained through such analysis.
Engineering design and theoretical analysis of nanoporous carbon membranes for gas separation
NASA Astrophysics Data System (ADS)
Acharya, Madhav
1999-11-01
Gases are used in a direct or indirect manner in virtually every major industry, such as steel manufacturing, oil production, foodstuffs and electronics. Membranes are being investigated as an alternative to established methods of gas separation such as pressure swing adsorption and cryogenic distillation. Membranes can be used in continuous operation and work very well at ambient conditions, thus representing a tremendous energy and economic saving over the other technologies. In addition, the integration of reaction and separation into a single unit known as a membrane reactor has the potential to revolutionize the chemical industry by making selective reactions a reality. Nanoporous carbons are highly disordered materials obtained from organic polymers or natural sources. They have the ability to separate gas molecules by several different mechanisms, and hence there is a growing effort to form them into membranes. In this study, nanoporous carbon membranes were prepared on macroporous stainless steel supports of both tubular and disk geometries. The precursor used was poly(furfuryl alcohol) and different synthesis protocols were employed. A spray coating method also was developed which allowed reproducible synthesis of membranes with very few defects. High gas selectivities were obtained such as O2/N2 = 6, H2/C2H 4 = 70 and CO2/N2 = 20. Membranes also were characterized using SEM and AFM, which revealed thin layers of carbon that were quite uniform and homogeneous. The simulation of nanoporous carbon structures also was carried out using a simple algorithmic approach. 5,6 and 7-membered rings were introduced into the structure, thus resulting in considerable curvature. The density of the structures were calculated and found to compare favorably with experimental findings. Finally, a theoretical analysis of size selective transport was performed using transition state theory concepts. A definite correlation of gas permeance with molecular size was obtained after
NASA Astrophysics Data System (ADS)
de, Dilip; Aziz de, Abdul
2012-10-01
The change of activation energy of a liquid molecule and hence its viscosity coefficient with addition of contaminants to the original liquid gives rise to a new technology for analysis of purity of the liquid. We discovered that concentration of certain contaminants such as water in alcohol or vice versa can be uniquely and accurately determined in a short time (about 10-15 minutes) using a simple and yet innovative technique that only requires measurement of time of flow of the impure liquid (say, water-alcohol mixture) and distilled water through a simple viscometer. We determined the increase of activation energy of alcohol molecules with increase of water concentration for ethyl and methyl alcohol. Our detailed investigation on the alcohol-water mixtures along with discussion on possible future potential application of the simple and very reliable inexpensive technique for liquid purity analysis is presented. We compared our present method with other methods on the accuracies, problems and reliability of impurity analysis in liquids. We also discuss a part of the quantum theory of viscosity of liquid mixtures that is in the developmental stage.
Analysis of chemoresistance in lung cancer with a simple microfluidic device.
Zhang, Lichuan; Wang, Jiarui; Zhao, Long; Meng, Qiang; Wang, Qi
2010-11-01
Microchip-based systems have been developed rapidly due to their desirable advantages over conventional platforms. Higher level system integration and complex microdevices are emerging to satisfy the demand for high-throughput and large-scale applications. However, most of the devices need to be fabricated with complicated microvalves and micropumps, which, to some extent, limit the use of the novel technique. In this study, a simple microdevice was developed to perform chemotherapy resistance analysis in lung cancer cell line SPCA1. This device includes a PDMS chip for which a simple external small clip served as a microvalve to control the fluid flow so that the parallel control experiment could be carried out simultaneously, and a syringe pump, which supplied the cells with fresh medium mimicking the microenvironment in vivo. Cell culture, detection of drug resistance related protein P-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) and cell viability after VP-16 treatment on experimental (pretreated with corresponding inhibitors) and control groups were achieved. The results demonstrated that the cells could grow and spread well for at least 3 days. The expression of P-gp and GST-π was obviously downregulated by corresponding inhibitors. The percentage of apoptotic cells for P-gp inhibition group increased 2.9-fold compared with that of control group (23.7 ± 2.6 versus 8.1 ± 3.0%, p<0.05), while for GST-π inhibition, there was no obvious distinction between the experimental and control group. The simple microdevice is capable of integrating parallel operations involving cell culture and functional analysis, offering an easy and flexible platform for a stable long-term cell culture and comparison research. PMID:20949633
Theoretical Noise Analysis on a Position-sensitive Metallic Magnetic Calorimeter
NASA Technical Reports Server (NTRS)
Smith, Stephen J.
2007-01-01
We report on the theoretical noise analysis for a position-sensitive Metallic Magnetic Calorimeter (MMC), consisting of MMC read-out at both ends of a large X-ray absorber. Such devices are under consideration as alternatives to other cryogenic technologies for future X-ray astronomy missions. We use a finite-element model (FEM) to numerically calculate the signal and noise response at the detector outputs and investigate the correlations between the noise measured at each MMC coupled by the absorber. We then calculate, using the optimal filter concept, the theoretical energy and position resolution across the detector and discuss the trade-offs involved in optimizing the detector design for energy resolution, position resolution and count rate. The results show, theoretically, the position-sensitive MMC concept offers impressive spectral and spatial resolving capabilities compared to pixel arrays and similar position-sensitive cryogenic technologies using Transition Edge Sensor (TES) read-out.
Simple spot method of image analysis for evaluation of highly marbled beef.
Irie, M; Kohira, K
2012-04-01
The simple method of evaluating highly marbled beef was examined by image analysis. The images of the cross section at the 6 to 7th rib were obtained from 82 carcasses of Wagyu cattle. By using an overall trace method, the surrounding edges of the longissimus thoracis and three muscles were traced automatically and manually with image analysis. In a spot method, 3 to 5 locations (2.5 or 3.0 cm in diameter) for each muscle were rapidly selected with no manual trace. The images were flattened, binarized, and the ratio of fat area to muscle area was determined. The correlation coefficients for marbling between different muscles, and between the overall trace and the spot methods were 0.55 to 0.81 between different muscles and 0.89 to 0.97, respectively. These results suggested that the simple spot method is speedy and almost as useful as the overall trace method as a measuring technique for beef marbling in loin muscles, especially for highly marbled beef. PMID:25049601
Analysis and Simple Circuit Design of Double Differential EMG Active Electrode.
Guerrero, Federico Nicolás; Spinelli, Enrique Mario; Haberman, Marcelo Alejandro
2016-06-01
In this paper we present an analysis of the voltage amplifier needed for double differential (DD) sEMG measurements and a novel, very simple circuit for implementing DD active electrodes. The three-input amplifier that standalone DD active electrodes require is inherently different from a differential amplifier, and general knowledge about its design is scarce in the literature. First, the figures of merit of the amplifier are defined through a decomposition of its input signal into three orthogonal modes. This analysis reveals a mode containing EMG crosstalk components that the DD electrode should reject. Then, the effect of finite input impedance is analyzed. Because there are three terminals, minimum bounds for interference rejection ratios due to electrode and input impedance unbalances with two degrees of freedom are obtained. Finally, a novel circuit design is presented, including only a quadruple operational amplifier and a few passive components. This design is nearly as simple as the branched electrode and much simpler than the three instrumentation amplifier design, while providing robust EMG crosstalk rejection and better input impedance using unity gain buffers for each electrode input. The interference rejection limits of this input stage are analyzed. An easily replicable implementation of the proposed circuit is described, together with a parameter design guideline to adjust it to specific needs. The electrode is compared with the established alternatives, and sample sEMG signals are obtained, acquired on different body locations with dry contacts, successfully rejecting interference sources. PMID:26841414
Bifurcation analysis of a simple analytic model of self-propagating star formation
NASA Technical Reports Server (NTRS)
Neukirch, Thomas; Hesse, Michael
1993-01-01
We investigate the structure and stability of rotationally symmetric nonhomogeneous time-independent solutions derived from a simple analytic model of self-propagating star formation. For this purpose we employ two methodologies: We use bifurcation theoretical methods to prove the existence of nonhomogeneous axisymmetric stationary solutions of an appropriate nonlinear evolution equation for the stellar density. We show that the nonhomogeneous solution branch bifurcates from the homogeneous one at a critical parameter value of the star formation rate. Further, the analytical theory allows us to show that the new solution set is stable in the weakly nonlinear regime near the bifurcation point. To follow the solution branch further, we use numerical methods. The numerical calculation shows the structure and stability of these solutions. We conclude that no periodic time-dependent solutions of this special model exist, and no further bifurcations can be found. The same results have been found in simulations of stochastic self-propagating star formation based on similar models. Therefore, our findings provide a natural explanation, why long-lived large-scale structure have not been found in those simulations.
Analysis of pipe flow with free surface. Part II. Theoretical analysis and experiment
NASA Astrophysics Data System (ADS)
Tanaka, Amane; Takaki, Ryuji
1994-05-01
Flow field near the front of an incompressible viscous fluid pushed into a circular pipe is analyzed theoretically and observed experimentally. In the theory, an approximated stream function for a steady state near the axis of the pipe is obtained by use of the Stokes equation. In the experiment, the shape of the surface was observed by a video camera. The theoretical velocity profile and the surface shape near the axis coincide with those from computation (Part I) and experiment.
NASA Astrophysics Data System (ADS)
Gunda, Jagadish Babu; Venkateswara Rao, Gundabathula
2016-04-01
Post-buckling and large amplitude free vibration analysis of composite beams with axially immovable ends is investigated in the present study using a simple intuitive formulation. Geometric nonlinearity of Von-Karman type is considered in the analysis which accounts for mid-plane stretching action of the beam. Intuitive formulation uses only two parameters: the critical bifurcation point and the axial stretching force developed due to membrane stretching action of the beam. Hinged-hinged, clamped-clamped and clamped-hinged boundary conditions are considered. Numerical accuracy of the proposed analytical closed-form solutions obtained from the intuitive formulation are compared to available finite element solutions for symmetric and asymmetric layup schemes of laminated composite beam which indicates the confidence gained on the present formulation.
A simple apparatus for quick qualitative analysis of CR39 nuclear track detectorsa)
NASA Astrophysics Data System (ADS)
Gautier, D. C.; Kline, J. L.; Flippo, K. A.; Gaillard, S. A.; Letzring, S. A.; Hegelich, B. M.
2008-10-01
Quantifying the ion pits in Columbia Resin 39 (CR39) nuclear track detector from Thomson parabolas is a time consuming and tedious process using conventional microscope based techniques. A simple inventive apparatus for fast screening and qualitative analysis of CR39 detectors has been developed, enabling efficient selection of data for a more detailed analysis. The system consists simply of a green He-Ne laser and a high-resolution digital single-lens reflex camera. The laser illuminates the edge of the CR39 at grazing incidence and couples into the plastic, acting as a light pipe. Subsequently, the laser illuminates all ion tracks on the surface. A high-resolution digital camera is used to photograph the scattered light from the ion tracks, enabling one to quickly determine charge states and energies measured by the Thomson parabola.
A simple apparatus for quick qualitative analysis of CR39 nuclear track detectors
Gautier, D. C.; Kline, J. L.; Flippo, K. A.; Gaillard, S. A.; Letzring, S. A.; Hegelich, B. M.
2008-10-15
Quantifying the ion pits in Columbia Resin 39 (CR39) nuclear track detector from Thomson parabolas is a time consuming and tedious process using conventional microscope based techniques. A simple inventive apparatus for fast screening and qualitative analysis of CR39 detectors has been developed, enabling efficient selection of data for a more detailed analysis. The system consists simply of a green He-Ne laser and a high-resolution digital single-lens reflex camera. The laser illuminates the edge of the CR39 at grazing incidence and couples into the plastic, acting as a light pipe. Subsequently, the laser illuminates all ion tracks on the surface. A high-resolution digital camera is used to photograph the scattered light from the ion tracks, enabling one to quickly determine charge states and energies measured by the Thomson parabola.
NASA Astrophysics Data System (ADS)
Ren, Peng; Zhang, Wei
2013-06-01
Dynamic response analysis of structures subjected to underwater explosion loading has been always an interesting field for researchers. Understanding the deformation and failure mechanism of simple structures plays an important role in an actual project under this kind of loading. In this paper, the deformation and failure characteristics of 5A06 aluminum circular plates were investigated computationally and theoretically. The computational study was based on a Johnson-cook material parameter mode which was obtained from several previous studies provides a good description of deformation and failure of 5A06 aluminum circular plates under underwater explosion loading. The deformation history of the clamped circular plate is recorded; the maximum deflection and the thickness reduction measurements of target plates at different radii were conducted. The computational approach provided insight into the relationship between the failure mechanism and the strength of impact wave, and a computing formulae for strain field of the specimen was derived based on the same volume principle and rigid-plastic assumption. The simulation and theoretical calculation results are in good agreement with the experiments results. National Natural Science Foundation of China (NO:11272057).
NASA Astrophysics Data System (ADS)
Bech, Joan; Gayà, Miquel; Aran, Montserrat; Figuerola, Francesc; Amaro, Jéssica; Arús, Joan
This paper deals with the application of a methodology to characterize tornado damage in forests based on a simple two dimensional stationary tornado vortex to describe the surface wind field. The basic vortex model is built over the traditional approach of a combined Rankine velocity profile with radial and azimuthal components plus a constant translational field. Several additions are considered such as producing theoretical swath patterns including absolute velocity values (to compare more easily with Fujita damage rating) or using radar data to estimate the translational speed of the vortex. The methodology is demonstrated with the Castellcir tornado that took place in Catalonia (NE Spain) on the 18th October 2006. The site survey indicated a 4 km path and 260 m maximum width as well as F2 damage. Further analysis suggests the existence of three stages in the tornado life cycle: 1) an organising stage with predominantly inflow pattern; 2) a mature stage with predominant tangential circulation of the vortex and maximum damage and width path -possibly influenced by the complex topography of the terrain-, and 3) a dissipating stage showing weakening and narrowing of the damage path but no outflow patterns. The methodology also helped to confirm the tornadic character of the damage discarding possible microbursts in some parts of the area surveyed.
Theoretical and experimental analysis of optical gyroscopes based on fiber ring resonators
NASA Astrophysics Data System (ADS)
Liu, Yao-ying; Xue, Chen-yang; Cui, Xiao-wen; Cui, Dan-feng; Wei, Li-ping; Wang, Yong-hua; Li, Yan-na
2014-12-01
The research on gyroscopes has lasted for a long time, but there is not a thorough analysis of them. In this paper, a detailed theoretical analysis of fiber ring gyroscope and its gyroscope effect were presented, the performance characteristics of optical resonator gyroscope ranging from transmission function Tfrr, Finesse, Q-factor, the gyro sensitivity, signal noise ratio, random walk to dynamic range are all deduced in detail. In addition, a large number of experiments have been done to verify the deduced theoretical results. Simulating the relevance of dQ and turn number of fiber ring, analyzing the frequency difference of two counter transmitted waves (CW and CCW) of the rotated system, make the conclusion that with the increase of turn number of ring, the resonance depth increased while the dQ value decreased, obtain a high sensitivity of 0.210/h, random walk of 0.00350/√h, and Q factor of 8×106. Moreover, in the digital frequency locked dual rotation gyro experiments, obvious step effect was observed. And the experimental line of frequency difference is very agreement with the theoretical line. The research provides a good theoretical and experimental basis for the study of gyroscopes.
NASA Technical Reports Server (NTRS)
Morse, D. R. A.; Sahlberg, J. T.
1977-01-01
The Pacific Northwest Land Resources Inventory Demonstration Project i s an a ttempt to combine a whole spectrum of heterogeneous geographic, institutional and applications elements in a synergistic approach to the evaluation of remote sensing techniques. This diversity is the prime motivating factor behind a theoretical investigation of alternative economic analysis procedures. For a multitude of reasons--simplicity, ease of understanding, financial constraints and credibility, among others--cost-effectiveness emerges as the most practical tool for conducting such evaluation determinatIons in the Pacific Northwest. Preliminary findings in two water resource application areas suggest, in conformity with most published studies, that Lands at-aided data collection methods enjoy substantial cost advantages over alternative techniques. The pntential for sensitivity analysis based on cost/accuracy tradeoffs is considered on a theoretical plane in the absence of current accuracy figures concerning the Landsat-aided approach.
Analysis of utility-theoretic heuristics for intelligent adaptive network routing
Mikler, A.R.; Honavar, V.; Wong, J.S.K.
1996-12-31
Utility theory offers an elegant and powerful theoretical framework for design and analysis of autonomous adaptive communication networks. Routing of messages in such networks presents a real-time instance of a multi-criterion optimization problem in a dynamic and uncertain environment. In this paper, we incrementally develop a set of heuristic decision functions that can be used to guide messages along a near-optimal (e.g., minimum delay) path in a large network. We present an analysis of properties of such heuristics under a set of simplifying assumptions about the network topology and load dynamics and identify the conditions under which they are guaranteed to route messages along an optimal path. The paper concludes with a discussion of the relevance of the theoretical results presented in the paper to the design of intelligent autonomous adaptive communication networks and an outline of some directions of future research.
A simple method for the analysis of neutron resonance capture spectra
Clarijs, Martijn C.; Bom, Victor R.; Eijk, Carel W. E. van
2009-03-15
Neutron resonance capture analysis (NRCA) is a method used to determine the bulk composition of various kinds of objects and materials. It is based on analyzing direct capture resonance peaks. However, the analysis is complicated by scattering followed by capture effects in the object itself. These effects depend on the object's shape and size. In this paper the new Delft elemental analysis program (DEAP) is presented which can automatically and quickly analyze multiple NRCA spectra in a practical and simple way, yielding the elemental bulk composition of an object, largely independent of its shape and size. The DEAP method is demonstrated with data obtained with a Roman bronze water tap excavated in Nijmegen (The Netherlands). DEAP will also be used in the framework of the Ancient Charm project as data analysis program for neutron resonance capture imaging (NRCI) experiments. NRCI provides three-dimensional visualization and quantification of the internal structure of archaeological objects by performing scanning measurements with narrowly collimated neutron beams on archaeological objects in computed tomography based experimental setups. The large amounts (hundreds to thousands) of spectra produced during a NRCI experiment can automatically and quickly be analyzed by DEAP.
Kaourma, E; Hatziantoniou, S; Georgopoulos, A; Kolocouris, A; Demetzos, C
2005-04-01
The aim of this study was to synthesize simple thiol-reactive conjugates from maleimide and lipoamines (stearylamine or oleylamine) and to develop a simple, fast and low-cost method for the preparation of lyophilized general-purpose thiol-reactive liposomes. A formulation of egg phosphatidylcholine-dipalmitoylphoshatidylglycerol (9:0.1 molar ratio) was developed and characterized. Freeze-drying methodology was established to produce a stock of liposomes and the physicochemical characteristics of the reconstituted liposomes were compared with those of the initial preparation. The physicochemical properties (size and zeta potential) of the new liposomal formulations were studied. High-performance thin-layer chromatography coupled to a flame ionization detector was applied for one-step analysis of the liposomal components and for determining the maleimide-lipoamine conjugates phospholipid molar ratio. The differences concerning the incorporation efficiency of the synthetic conjugates into liposomes were discussed on the basis of their conformational properties. The small difference in structure between the two thiol-reactive conjugates (i.e., the C18 alkyl chain double bond) causes a considerable difference in phospholipids packing of the resulting lipidic bilayers of the liposomes; the conformational bending of conjugate maleimide-oleylamine may contribute to the final architecture of liposomes. PMID:15831216
Zhai, Haiyun; Yuan, Kaisong; Yu, Xiao; Chen, Zuanguang; Liu, Zhenping; Su, Zihao
2015-10-01
A novel fluorescence detection system for CE was described and evaluated. Two miniature laser pointers were used as the excitation source. A Y-style optical fiber was used to transmit the excitation light and a four-branch optical fiber was used to collect the fluorescence. The optical fiber and optical filter were imported into a photomultiplier tube without any extra fixing device. A simplified PDMS detection cell was designed with guide channels through which the optical fibers were easily aligned to the detection window of separation capillary. According to different requirements, laser pointers and different filters were selected by simple switching and replacement. The fluorescence from four different directions was collected at the same detecting point. Thus, the sensitivity was enhanced without peak broadening. The fluorescence detection system was simple, compact, low-cost, and highly sensitive, with its functionality demonstrated by the separation and determination of red dyes and fluorescent whitening agents. The detection limit of rhodamine 6G was 7.7 nM (S/N = 3). The system was further applied to determine illegal food dyes. The CE system is potentially eligible for food safety analysis. PMID:26109527
Analysis of a theoretical model for anisotropic enzyme membranes application to enzyme electrodes.
Pedersen, H; Chotani, G K
1981-12-01
A theoretical model of diffusion and reaction in an anisotropic enzyme membrane is presented with particular emphasis on the application of such membranes in enzyme electrodes. The dynamic response of systems in which the kinetics are linear, which comprises the practical operating regime for enzyme electrodes in analysis, is investigated via an analytic solution of the governing differential equations. The response is presented as a function of a single dimensionless group, Μ, that is the membrane modulus. PMID:24233978
NASA Technical Reports Server (NTRS)
Middleton, W. D.; Lundry, J. L.
1975-01-01
An integrated system of computer programs has been developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. This part presents a general description of the system and describes the theoretical methods used.
Can Computer-Mediated Interventions Change Theoretical Mediators of Safer Sex? A Meta-Analysis
ERIC Educational Resources Information Center
Noar, Seth M.; Pierce, Larson B.; Black, Hulda G.
2010-01-01
The purpose of this study was to conduct a meta-analysis of computer-mediated interventions (CMIs) aimed at changing theoretical mediators of safer sex. Meta-analytic aggregation of effect sizes from k = 20 studies indicated that CMIs significantly improved HIV/AIDS knowledge, d = 0.276, p less than 0.001, k = 15, N = 6,625; sexual/condom…
NASA Technical Reports Server (NTRS)
Gates, Ordway B., Jr.; Woodling, C. H.
1959-01-01
Theoretical analysis of the longitudinal behavior of an automatically controlled supersonic interceptor during the attack phase against a nonmaneuvering target is presented. Control of the interceptor's flight path is obtained by use of a pitch rate command system. Topics lift, and pitching moment, effects of initial tracking errors, discussion of normal acceleration limited, limitations of control surface rate and deflection, and effects of neglecting forward velocity changes of interceptor during attack phase.
Experimental and theoretical analysis of bias ionization by α-particles in a nitrogen laser
NASA Astrophysics Data System (ADS)
Silva, R. R.; Vieira Mendes, L. A.; Tsui, K. H.; De Simone Zanon, R. A.; de Oliveira, A. L.; Fellows, C. E.
2011-09-01
Nitrogen laser performance with TE configuration and wedge electrodes is analyzed with background ionization in the laser discharge channel by α particles at a low exposition rate. With the bias ionization, the laser power presents two peaks as a function of gas pressure, with one at the normal low pressure, without bias ionization, and the other at high pressure generated by bias ionization. A simple theoretical model has been developed in a trial to understand this behavior. This model was first tested in later results for a TE configuration nitrogen laser, with flat electrodes, without and with bias ionization. It has been observed that due to the competition between electrode shielding by positively charged α particles and bulk ionization by impact, the laser energy is suppressed with pressure below 50 Torr and enhanced above it.
Hasan, Khader M.
2007-01-01
In this Communication, a theoretical framework for quality control and parameter optimization in diffusion tensor imaging (DTI) is presented and validated. The approach is based on the analytical error propagation of the mean diffusivity (Dav) obtained directly from the diffusion-weighted data (DW) acquired using rotationally-invariant and uniformly distributed icosahedral encoding schemes. The error propagation of a recently described and validated cylindrical tensor model is further extrapolated to the spherical tensor case (diffusion anisotropy ~ 0) to relate analytically the precision error in fractional tensor anisotropy (FA) with the mean diffusion signal-to-noise ratio (DNR). The approach provided simple analytical and empirical quality control measures for optimization of diffusion parameter space in an isotropic medium that can be tested using widely available water phantoms. PMID:17442523
A simple, low-cost staining method for rapid-throughput analysis of tumor spheroids
Eckerdt, Frank; Alvarez, Angel; Bell, Jonathan; Arvanitis, Constadina; Iqbal, Asneha; Arslan, Ahmet D.; Hu, Bo; Cheng, Shi-Yuan; Goldman, Stewart; Platanias, Leonidas C.
2016-01-01
Tumor spheroids are becoming an important tool for the investigation of cancer stem cell (CSC) function in tumors; thus, low-cost and high-throughput methods for drug screening of tumor spheroids are needed. Using neurospheres as non-adherent three-dimensional (3-D) cultures, we developed a simple, low-cost acridine orange (AO)–based method that allows for rapid analysis of live neurospheres by fluorescence microscopy in a 96-well format. This assay measures the cross-section area of a spheroid, which corresponds to cell viability. Our novel method allows rapid screening of a panel of anti-proliferative drugs to assess inhibitory effects on the growth of cancer stem cells in 3-D cultures. PMID:26757811
ERIC Educational Resources Information Center
Hsu, Anne S.; Chater, Nick; Vitanyi, Paul M. B.
2011-01-01
There is much debate over the degree to which language learning is governed by innate language-specific biases, or acquired through cognition-general principles. Here we examine the probabilistic language acquisition hypothesis on three levels: We outline a novel theoretical result showing that it is possible to learn the exact "generative model"…
Analysis of simple 2-D and 3-D metal structures subjected to fragment impact
NASA Technical Reports Server (NTRS)
Witmer, E. A.; Stagliano, T. R.; Spilker, R. L.; Rodal, J. J. A.
1977-01-01
Theoretical methods were developed for predicting the large-deflection elastic-plastic transient structural responses of metal containment or deflector (C/D) structures to cope with rotor burst fragment impact attack. For two-dimensional C/D structures both, finite element and finite difference analysis methods were employed to analyze structural response produced by either prescribed transient loads or fragment impact. For the latter category, two time-wise step-by-step analysis procedures were devised to predict the structural responses resulting from a succession of fragment impacts: the collision force method (CFM) which utilizes an approximate prediction of the force applied to the attacked structure during fragment impact, and the collision imparted velocity method (CIVM) in which the impact-induced velocity increment acquired by a region of the impacted structure near the impact point is computed. The merits and limitations of these approaches are discussed. For the analysis of 3-d responses of C/D structures, only the CIVM approach was investigated.
Nonlinear bend stiffener analysis using a simple formulation and finite element method
NASA Astrophysics Data System (ADS)
Tong, Dong Jin; Low, Ying Min; Sheehan, John M.
2011-12-01
Flexible marine risers are commonly used in deepwater floating systems. Bend stiffeners are designed to protect flexible risers against excessive bending at the connection with the hull. The structure is usually analyzed as a cantilever beam subjected to an inclined point load. As deflections are large and the bend stiffener material exhibits nonlinear stress-strain characteristics, geometric and material nonlinearities are important considerations. A new approach has been developed to solve this nonlinear problem. Its main advantage is its simplicity; in fact the present method can be easily implemented on a spreadsheet. Finite element analysis using ABAQUS is performed to validate the method. Solid elements are used for the bend stiffener and flexible pipe. To simulate the near inextensibility of flexible risers, a simple and original idea of using truss elements is proposed. Through a set of validation studies, the present method is found to be in a good agreement with the finite element analysis. Further, parametric studies are performed by using both methods to identify the key parameters and phenomena that are most critical in design. The most important finding is that the common practice of neglecting the internal steel sleeve in the bend stiffener analysis is non-conservative and therefore needs to be reassessed.
NASA Astrophysics Data System (ADS)
Génot, V.; André, N.; Cecconi, B.; Bouchemit, M.; Budnik, E.; Bourrel, N.; Gangloff, M.; Dufourg, N.; Hess, S.; Modolo, R.; Renard, B.; Lormant, N.; Beigbeder, L.; Popescu, D.; Toniutti, J.-P.
2014-11-01
The interest for data communication between analysis tools in planetary sciences and space physics is illustrated in this paper via several examples of the uses of SAMP. The Simple Application Messaging Protocol is developed in the frame of the IVOA from an earlier protocol called PLASTIC. SAMP enables easy communication and interoperability between astronomy software, stand-alone and web-based; it is now increasingly adopted by the planetary sciences and space physics community. Its attractiveness is based, on one hand, on the use of common file formats for exchange and, on the other hand, on established messaging models. Examples of uses at the CDPP and elsewhere are presented. The CDPP (Centre de Données de la Physique des Plasmas, http://cdpp.eu/), the French data center for plasma physics, is engaged for more than a decade in the archiving and dissemination of data products from space missions and ground observatories. Besides these activities, the CDPP developed services like AMDA (Automated Multi Dataset Analysis, http://amda.cdpp.eu/) which enables in depth analysis of large amount of data through dedicated functionalities such as: visualization, conditional search and cataloging. Besides AMDA, the 3DView (http://3dview.cdpp.eu/) tool provides immersive visualizations and is further developed to include simulation and observational data. These tools and their interactions with each other, notably via SAMP, are presented via science cases of interest to planetary sciences and space physics communities.
A simple ion chromatography method for inorganic anion analysis in edible seaweeds.
Gómez-Ordóñez, Eva; Alonso, Esther; Rupérez, Pilar
2010-09-15
A new, simple, fast and sensitive ion chromatography (IC) method, for the simultaneous analysis of fluoride, chloride, nitrite, bromide, nitrate, phosphate and sulphate in edible seaweeds was developed and reported for the first time. The validation of the analytical method was studied in terms of linearity, sensitivity, precision and accuracy. All standard calibration curves showed very good correlation between anion peak area and concentration (r>0.999). Limits of detection and quantitation ranged between 0.002-0.05 mg/L and 0.01-0.1mg/L, respectively and indicated the high sensitivity of the method. Relative standard deviation values of repeatability and inter-day precision for standard anions with the same sample were less than 2%. Anion recoveries ranged from 97 to 113% for chloride and from 87 to 105% for sulphate, respectively and showed the fairly good accuracy of the method. The method was applied to the analysis of inorganic anions in brown and red edible seaweeds. Brown seaweeds were characterized by higher chloride content up to 33.7-36.9%, while red seaweeds were characterized by higher sulphate content (45-57%). Sulphate content in seaweeds is related to the presence of sulphated polysaccharides of biological importance. The method developed was well applicable to mineral anion analysis in edible seaweeds and shows suitability and reliability of use in other food samples of nutritional importance. PMID:20801334
AppEEARS: Simple and Intuitive Access to Analysis Ready Data
NASA Astrophysics Data System (ADS)
Quenzer, R.; Friesz, A. M.
2015-12-01
Many search and discovery tools for satellite land remote sensing data archives are often catalog-based and can only be queried at a granule level requiring remote sensing data users to download and process entire data files before science questions can be addressed. Methods for accessing remote sensing data archives must become more precise in order to allow users to concisely extract study relevant information from rapidly expanding archives. To address the need, NASA's Land Processes Distributed Active Archive Center (LP DAAC) is developing AppEEARS (Application for Extracting and Exploring Analysis Ready Samples). Built on top of middleware services, the AppEEARS user interface facilitates input of precise sample locations, such as field study sites or flux towers, to extract analysis-ready data from land MODIS products held by NASA's LP DAAC. AppEEARS provides simple and intuitive access to LP DAAC's land MODIS products. For a given set of sample locations, AppEEARS returns pixel values that intersect with the provided locations through the requested date range. Additionally, the AppEEARS user interface provides exploratory data analysis services (e.g. time series and scatter plots) allowing users to interact and explore the requested data and its associated quality information before downloading. AppEEARS delivers study relevant data sets requiring little more processing allowing users to spend less time performing data preparation routines and more time answer questions.
Simple peak shift analysis of time-of-flight data with a slow instrumental response function.
Nishimura, Goro; Tamura, Mamoru
2005-01-01
Analysis of time-of-flight (TOF) data is sometimes limited by the instrumental response function, and optical parameters are extracted from the observed response curve by several mathematical methods, such as deconvolution. In contrast to this, we demonstrate that a method using shifts of the peak time of the response curve with different source-detector separations can yield the average path length of the light traveling in a tissue-like sample without deconvolution. In addition, combining the intensity information allows us to separate the scattering and absorption coefficients. This simple method is more robust in signal-to-noise ratio than the moment analysis, which also does not require the deconvolution procedure, because the peak position is not significantly dependent on the baseline fluctuation and the contamination of the scattering. The analysis is demonstrated by TOF measurements of an Intralipid solution at 800 nm, and is applied to the measurements at 1.29 microm, where the temporal response of photomultiplier tubes is not sufficiently good. PMID:15847597
Theoretical analysis of surface stress for a microcantilever with varying widths
NASA Astrophysics Data System (ADS)
Li, Xian-Fang; Peng, Xu-Long
2008-03-01
A theoretical model of surface stress is developed in this paper for a microcantilever with varying widths, and a method for calculating the surface stress via static deflection, slope angle or radius at curvature of the cantilever beam is presented. This model assumes that surface stresses are uniformly distributed on one surface of the cantilever beam. Based on this stressor model and using the small deformation Euler-Bernoulli beam theory, a fourth-order ordinary differential governing equation with varying coefficients or an equivalent second-order integro-differential equation is derived. A simple approach is then proposed to determine the solution of the resulting equation, and a closed-form approximate solution with high accuracy can be obtained. For rectangular and V-shaped microfabricated cantilevers, the dependences of transverse deflection, slope and curvature of the beam on the surface stresses are given explicitly. The obtained results indicate that the zeroth order approximation of the stressor model reduces to the end force model with a linear curvature for a rectangular cantilever. For larger surface stresses, the curvature exhibits a non-linear behaviour. The predictions through the stressor model give higher accuracy than those from the end moment and end force models and satisfactorily agree with experimental data. The derived closed-form solution can serve as a theoretical benchmark for verifying numerically obtained results for microcantilevers as atomic force microscopy and micromechanical sensors.
Isshiki, Seita; Isshiki, Naotsugu; Takanose, Eiichiro; Igawa, Yoshiharu
1995-12-31
This paper describes the detailed experimental and theoretical performance of new type Stirling engine with pendulum type displacer (PDSE) which was proposed last year. This kind of engine has a pendulum type displacer suspended by the hinge shaft, and swings right and left in displacer space. The present paper mainly discusses the PDSE-3B which is an atmospheric 30[W] engine heated by fuel and cooled by water. It is clear that power required to provide a pendulum type displacer motion is expressed as a simple equation consisting of viscous flow loss term proportional to the square of rotational speed and dynamic pressure loss term proportional to the cube of rotational speed. It is also clear that theoretical engine power defined as the difference between experimental indicated power and power required to provide pendulum type displacer motion agrees well with the experimental engine power. It is also clear that measured Nusselt number of regenerator`s wire meshes agreed with the equation of previous study. In conclusion, PDSE is considered effective for measuring many aspects of performance of the Stirling engine.
Blade loss transient dynamics analysis, volume 1. Task 2: TETRA 2 theoretical development
NASA Technical Reports Server (NTRS)
Gallardo, Vincente C.; Black, Gerald
1986-01-01
The theoretical development of the forced steady state analysis of the structural dynamic response of a turbine engine having nonlinear connecting elements is discussed. Based on modal synthesis, and the principle of harmonic balance, the governing relations are the compatibility of displacements at the nonlinear connecting elements. There are four displacement compatibility equations at each nonlinear connection, which are solved by iteration for the principle harmonic of the excitation frequency. The resulting computer program, TETRA 2, combines the original TETRA transient analysis (with flexible bladed disk) with the steady state capability. A more versatile nonlinear rub or bearing element which contains a hardening (or softening) spring, with or without deadband, is also incorporated.
ERIC Educational Resources Information Center
Hijnen, Hens
2009-01-01
A theoretical description of the influence of electroosmosis on the effective mobility of simple ions in capillary zone electrophoresis is presented. The mathematical equations derived from the space-charge model contain the pK[subscript a] value and the density of the weak acid surface groups as parameters characterizing the capillary. It is…
NASA Astrophysics Data System (ADS)
First, Leili K.
This dissertation investigates the intersections and interactions of factors which enhance and inhibit creativity in theoretical physics research, using a situational analysis of the fifth Solvay Council on Physics of 1927 (Solvay 1927), a pivotal point in the history of quantum physics. Situational analysis is a postmodern variant of the grounded theory method which views a situation as the unit of analysis and adds situational mapping as an analytic tool. This method specifically works against normalizing or simplifying the points of view, instead drawing out diversity, complexity, and contradiction. It results in "theorizing" rather than theory. This research differs from other analyses of the development of quantum mechanics in looking at technical issues as well as individual, collective, and societal factors. Data examined in this historical analysis includes theoretical papers, conference proceedings, personal letters, and commentary and analysis, both contemporaneous and modern. Literature related to scientific creativity was also consulted. Mapping the situation as a master discourse of Niels Bohr overlapping and interacting with co-existent major discourses on matrix mechanics/Copenhagen interpretation, wave mechanics, and the pilot-wave theory resulted in the most descriptive illustration of the factors influencing scientific creativity before and after Solvay 1927. The master discourse strongly influenced the major discourses and generated the "Copenhagen spirit" which effectively marginalized discourses other than matrix mechanics/Copenhagen interpretation after Solvay 1927.
An Experimental-Theoretical Analysis of Protein Adsorption on Peptidomimetic Polymer Brushes
Lau, K.H. Aaron; Ren, Chunlai; Park, Sung Hyun; Szleifer, Igal; Messersmith, Phillip B.
2012-01-01
Surface-grafted water soluble polymer brushes are being intensely investigated for preventing protein adsorption to improve biomedical device function, prevent marine fouling, and enable applications in biosensing and tissue engineering. In this contribution, we present an experimental-theoretical analysis of a peptidomimetic polymer brush system with regard to the critical brush density required for preventing protein adsorption at varying chain lengths. A mussel adhesive-inspired DOPA-Lys pentapeptide surface grafting motif enabled aqueous deposition of our peptidomimetic polypeptoid brushes over a wide range of chain densities. Critical densities of 0.88 nm−2 for a relatively short polypeptoid 10-mer to 0.42 nm−2 for a 50-mer were identified from measurements of protein adsorption. The experiments were also compared with the protein adsorption isotherms predicted by a molecular theory. Excellent agreements in terms of both the polymer brush structure and the critical chain density were obtained. Furthermore, atomic force microscopy (AFM) imaging is shown to be useful in verifying the critical brush density for preventing protein adsorption. The present co-analysis of experimental and theoretical results demonstrates the significance of characterizing the critical brush density in evaluating the performance of an anti-fouling polymer brush system. The high fidelity of the agreement between the experiments and molecular theory also indicate that the theoretical approach presented can aid in the practical design of antifouling polymer brush systems. PMID:22107438
Analysis of cyclic enzyme reaction schemes by the graph-theoretic method.
Goldstein, B N
1983-07-21
The development of the graph-theoretic method is proposed particularly for the analysis of closed cycles of elementary stages in enzyme reaction schemes. Some simplifications of the graph structure may be based on the application of Kirchhoff's laws to enzyme reaction graphs in the steady-state. The importance of the cyclic processes for enzyme regulations and a principle non-equilibrium of this phenomenon are emphasized. As an example of the regulatory role of cycles "the liberation" from substrate inhibition by substrate analogues is considered. The modification of the graph-theoretic method in the pre-steady-state kinetics for arbitrary initial conditions (for pre-mixing procedures) is also discussed. The necessary and sufficient conditions for damped oscillations in the pre-steady state are formulated which are the equality conditions for some of the rate constants along the cycle (both for reversible and irreversible stages). PMID:6621072
A Simple Method of Genomic DNA Extraction from Human Samples for PCR-RFLP Analysis
Ghatak, Souvik; Muthukumaran, Rajendra Bose; Nachimuthu, Senthil Kumar
2013-01-01
Isolation of DNA from blood and buccal swabs in adequate quantities is an integral part of forensic research and analysis. The present study was performed to determine the quality and the quantity of DNA extracted from four commonly available samples and to estimate the time duration of the ensuing PCR amplification. Here, we demonstrate that hair and urine samples can also become an alternate source for reliably obtaining a small quantity of PCR-ready DNA. We developed a rapid, cost-effective, and noninvasive method of sample collection and simple DNA extraction from buccal swabs, urine, and hair using the phenol-chloroform method. Buccal samples were subjected to DNA extraction, immediately or after refrigeration (4–6°C) for 3 days. The purity and the concentration of the extracted DNA were determined spectrophotometerically, and the adequacy of DNA extracts for the PCR-based assay was assessed by amplifying a 1030-bp region of the mitochondrial D-loop. Although DNA from all the samples was suitable for PCR, the blood and hair samples provided a good quality DNA for restriction analysis of the PCR product compared with the buccal swab and urine samples. In the present study, hair samples proved to be a good source of genomic DNA for PCR-based methods. Hence, DNA of hair samples can also be used for the genomic disorder analysis in addition to the forensic analysis as a result of the ease of sample collection in a noninvasive manner, lower sample volume requirements, and good storage capability. PMID:24294115
Analysis system for characterisation of simple, low-cost microfluidic components
NASA Astrophysics Data System (ADS)
Smith, Suzanne; Naidoo, Thegaran; Nxumalo, Zandile; Land, Kevin; Davies, Emlyn; Fourie, Louis; Marais, Philip; Roux, Pieter
2014-06-01
There is an inherent trade-off between cost and operational integrity of microfluidic components, especially when intended for use in point-of-care devices. We present an analysis system developed to characterise microfluidic components for performing blood cell counting, enabling the balance between function and cost to be established quantitatively. Microfluidic components for sample and reagent introduction, mixing and dispensing of fluids were investigated. A simple inlet port plugging mechanism is used to introduce and dispense a sample of blood, while a reagent is released into the microfluidic system through compression and bursting of a blister pack. Mixing and dispensing of the sample and reagent are facilitated via air actuation. For these microfluidic components to be implemented successfully, a number of aspects need to be characterised for development of an integrated point-of-care device design. The functional components were measured using a microfluidic component analysis system established in-house. Experiments were carried out to determine: 1. the force and speed requirements for sample inlet port plugging and blister pack compression and release using two linear actuators and load cells for plugging the inlet port, compressing the blister pack, and subsequently measuring the resulting forces exerted, 2. the accuracy and repeatability of total volumes of sample and reagent dispensed, and 3. the degree of mixing and dispensing uniformity of the sample and reagent for cell counting analysis. A programmable syringe pump was used for air actuation to facilitate mixing and dispensing of the sample and reagent. Two high speed cameras formed part of the analysis system and allowed for visualisation of the fluidic operations within the microfluidic device. Additional quantitative measures such as microscopy were also used to assess mixing and dilution accuracy, as well as uniformity of fluid dispensing - all of which are important requirements towards the
A simple method of observation impact analysis for operational storm surge forecasting systems
NASA Astrophysics Data System (ADS)
Sumihar, Julius; Verlaan, Martin
2016-04-01
In this work, a simple method is developed for analyzing the impact of assimilating observations in improving forecast accuracy of a model. The method simply makes use of observation time series and the corresponding model output that are generated without data assimilation. These two time series are usually available in an operational database. The method is therefore easy to implement. Moreover, it can be used before actually implementing any data assimilation to the forecasting system. In this respect, it can be used as a tool for designing a data assimilation system, namely for searching for an optimal observing network. The method can also be used as a diagnostic tool, for example, for evaluating an existing operational data assimilation system to check if all observations are contributing positively to the forecast accuracy. The method has been validated with some twin experiments using a simple one-dimensional advection model as well as with an operational storm surge forecasting system based on the Dutch Continental Shelf model version 5 (DCSMv5). It has been applied for evaluating the impact of observations in the operational data assimilation system with DCSMv5 and for designing a data assimilation system for the new model DCSMv6. References: Verlaan, M. and J. Sumihar (2016), Observation impact analysis methods for storm surge forecasting systems, Ocean Dynamics, ODYN-D-15-00061R1 (in press) Zijl, F., J. Sumihar, and M. Verlaan (2015), Application of data assimilation for improved operational water level forecasting of the northwest European shelf and North Sea, Ocean Dynamics, 65, Issue 12, pp 1699-1716.
Belal, Tarek Saied
2008-09-01
A simple, rapid, selective and sensitive spectrofluorimetric method was described for the analysis of three nitrofuran drugs, namely, nifuroxazide (NX), nitrofurantoin (NT) and nitrofurazone (NZ). The method involved the alkaline hydrolysis of the studied drugs by warming with 0.1 M sodium hydroxide solution then dilution with distilled water for NX or 2-propanol for NT and NZ. The formed fluorophores were measured at 465 nm (lambda (Ex) 265 nm), 458 nm (lambda (Ex) 245 nm) and 445 nm (lambda (Ex) 245 nm) for NX, NT and NZ, respectively. The reaction pathway was discussed and the structures of the fluorescent products were proposed. The different experimental parameters were studied and optimized. Regression analysis showed good correlation between fluorescence intensity and concentration over the ranges 0.08-1.00, 0.02-0.24 and 0.004-0.050 microg ml(-1) for NX, NT and NZ, respectively. The limits of detection of the method were 8.0, 1.9 and 0.3 ng ml(-1) for NX, NT and NZ, respectively. The proposed method was validated in terms of accuracy, precision and specificity, and it was successfully applied for the assay of the three nitrofurans in their different dosage forms. No interference was observed from common pharmaceutical adjuvants. The results were favorably compared with those obtained by reference spectrophotometric methods. PMID:18246413
A rapid and simple HPLC method for the analysis of propofol in biological fluids.
Cussonneau, Xavier; De Smet, Els; Lantsoght, Kristof; Salvi, Jean-Paul; Bolon-Larger, Magali; Boulieu, Roselyne
2007-07-27
A selective and sensitive high-performance liquid chromatographic method for the analysis of propofol in biological samples was developed. Propofol and thymol (internal standard) were analysed on a Purospher RP-18 endcapped (75 mmx4 mm, 3 microm) stationary phase using acetonitrile and water (65:35, v/v) as eluents at a flow rate of 0.6 mL/min. The excitation and emission wavelengths were 276 and 310 nm, respectively. Sample treatment consisted of deproteinization by acetonitrile containing the internal standard and direct injection of the supernatant. Mean analytical recovery were 105% (CV 2.0%) at concentrations ranging from 0.05 to 10 mg/L. The quantification limit was 3 ng/mL for a 500 microL sample plasma volume and 5 ng/mL for a 500 microL blood sample. The intra-day and inter-day precisions were lower than 5.5% for three concentrations assessed (0.05, 1.0 and 10.0 mg/L). Considering the column size and the flow rate, the separation was achieved with an analysis time less than 6 min with a reduced consumption of solvent. This rapid HPLC method using a simple treatment procedure is sensitive enough for monitoring propofol in human biological samples. PMID:17129698
Habas, Piotr A; Zurada, Jacek M; Elmaghraby, Adel S; Tourassi, Georgia D
2006-01-01
The purpose of this study is to develop and evaluate a probabilistic framework for reliability analysis of information-theoretic computer-assisted detection (IT-CAD) systems in mammography. The study builds upon our previous work on a feature-based reliability analysis technique tailored to traditional CAD systems developed with a supervised learning scheme. The present study proposes a probabilistic framework to facilitate application of the reliability analysis technique for knowledge-based CAD systems that are not feature-based. The study was based on an information-theoretic CAD system developed for detection of masses in screening mammograms from the Digital Database for Screening Mammography (DDSM). The experimental results reveal that the query-specific reliability estimate provided by the proposed probabilistic framework is an accurate predictor of CAD performance for the query case. It can also be successfully applied as a base for stratification of CAD predictions into clinically meaningful reliability groups (i.e., HIGH, MEDIUM, and LOW). Based on a leave-one-out sampling scheme and ROC analysis, the study demonstrated that the diagnostic performance of the IT-CAD is significantly higher for cases with HIGH reliability (A(z) = 0.92 +/- 0.03) than for those stratified as MEDIUM (A(z) = 0.84 +/- 0.02) or LOW reliability predictions (A(z) = 0.78 +/- 0.02). PMID:17946741
Matsuda, Hiroshi; Ota, Miho; Maikusa, Norihide; Kimura, Yukio; Sumida, Kaoru; Yokoyama, Kota; Imabayashi, Etsuko; Watanabe, Masako; Watanabe, Yutaka; Okazaki, Mitsutoshi; Sato, Noriko
2016-01-01
Purpose Psychosis is one of the most important psychiatric comorbidities in temporal lobe epilepsy (TLE), and its pathophysiology still remains unsolved. We aimed to explore the connectivity differences of structural neuroimaging between TLE with and without psychosis using a graph theoretical analysis, which is an emerging mathematical method to investigate network connections in the brain as a small-world system. Materials and Methods We recruited 11 TLE patients with unilateral hippocampal sclerosis (HS) presenting psychosis or having a history of psychosis (TLE-P group). As controls, 15 TLE patients with unilateral HS without any history of psychotic episodes were also recruited (TLE-N group). For graph theoretical analysis, the normalized gray matter images of both groups were subjected to Graph Analysis Toolbox (GAT). As secondary analyses, each group was compared to 14 age- and gender-matched healthy subjects. Results The hub node locations were found predominantly in the ipsilateral hemisphere in the TLE-N group, and mainly on the contralateral side in the TLE-P group. The TLE-P group showed significantly higher characteristic path length, transitivity, lower global efficiency, and resilience to random or targeted attack than those of the TLE-N group. The regional comparison in betweenness centrality revealed significantly decreased connectivity in the contralateral temporal lobe, ipsilateral middle frontal gyrus, and bilateral postcentral gyri in the TLE-P group. The healthy subjects showed well-balanced nodes/edges distributions, similar metrics to TLE-N group except for higher small-worldness/modularity/assortativity, and various differences of regional betweenness/clustering. Conclusion In TLE with psychosis, graph theoretical analysis of structural imaging revealed disrupted connectivity in the contralateral hemisphere. The network metrics suggested that the existence of psychosis can bring vulnerability and decreased efficiency of the whole
NASA Astrophysics Data System (ADS)
Michalska, Katarzyna; Mizera, Mikołaj; Lewandowska, Kornelia; Cielecka-Piontek, Judyta
2016-07-01
Tedizolid is the newest antibacterial agent from the oxazolidinone class. For its identification, FT-IR (2000-400 cm-1) and Raman (2000-400 cm-1) analyses were proposed. Studies of the enantiomeric purity of tedizolid were conducted based on ultraviolet-circular dichroism (UV-CD) analysis. Density functional theory (DFT) with the B3LYP hybrid functional and 6-311G(2df,2pd) basis set was used for support of the analysis of the FT-IR and Raman spectra. Theoretical methods made it possible to conduct HOMO and LUMO analysis, which was used to determine the charge transfer for two tedizolid enantiomers. Molecular electrostatic potential maps were calculated with the DFT method for both tedizolid enantiomers. The relationship between the results of ab initio calculations and knowledge about the chemical-biological properties of R- and S-tedizolid enantiomers is also discussed.
Dream-reality confusion in borderline personality disorder: a theoretical analysis.
Skrzypińska, Dagna; Szmigielska, Barbara
2015-01-01
This paper presents an analysis of dream-reality confusion (DRC) in relation to the characteristics of borderline personality disorder (BPD), based on research findings and theoretical considerations. It is hypothesized that people with BPD are more likely to experience DRC compared to people in non-clinical population. Several variables related to this hypothesis were identified through a theoretical analysis of the scientific literature. Sleep disturbances: problems with sleep are found in 15-95.5% of people with BPD (Hafizi, 2013), and unstable sleep and wake cycles, which occur in BPD (Fleischer et al., 2012), are linked to DRC. Dissociation: nearly two-thirds of people with BPD experience dissociative symptoms (Korzekwa and Pain, 2009) and dissociative symptoms are correlated with a fantasy proneness; both dissociative symptoms and fantasy proneness are related to DRC (Giesbrecht and Merckelbach, 2006). Negative dream content: People with BPD have nightmares more often than other people (Semiz et al., 2008); dreams that are more likely to be confused with reality tend to be more realistic and unpleasant, and are reflected in waking behavior (Rassin et al., 2001). Cognitive disturbances: Many BPD patients experience various cognitive disturbances, including problems with reality testing (Fiqueierdo, 2006; Mosquera et al., 2011), which can foster DRC. Thin boundaries: People with thin boundaries are more prone to DRC than people with thick boundaries, and people with BPD tend to have thin boundaries (Hartmann, 2011). The theoretical analysis on the basis of these findings suggests that people who suffer from BPD may be more susceptible to confusing dream content with actual waking events. PMID:26441768
Dream-reality confusion in borderline personality disorder: a theoretical analysis
Skrzypińska, Dagna; Szmigielska, Barbara
2015-01-01
This paper presents an analysis of dream-reality confusion (DRC) in relation to the characteristics of borderline personality disorder (BPD), based on research findings and theoretical considerations. It is hypothesized that people with BPD are more likely to experience DRC compared to people in non-clinical population. Several variables related to this hypothesis were identified through a theoretical analysis of the scientific literature. Sleep disturbances: problems with sleep are found in 15–95.5% of people with BPD (Hafizi, 2013), and unstable sleep and wake cycles, which occur in BPD (Fleischer et al., 2012), are linked to DRC. Dissociation: nearly two-thirds of people with BPD experience dissociative symptoms (Korzekwa and Pain, 2009) and dissociative symptoms are correlated with a fantasy proneness; both dissociative symptoms and fantasy proneness are related to DRC (Giesbrecht and Merckelbach, 2006). Negative dream content: People with BPD have nightmares more often than other people (Semiz et al., 2008); dreams that are more likely to be confused with reality tend to be more realistic and unpleasant, and are reflected in waking behavior (Rassin et al., 2001). Cognitive disturbances: Many BPD patients experience various cognitive disturbances, including problems with reality testing (Fiqueierdo, 2006; Mosquera et al., 2011), which can foster DRC. Thin boundaries: People with thin boundaries are more prone to DRC than people with thick boundaries, and people with BPD tend to have thin boundaries (Hartmann, 2011). The theoretical analysis on the basis of these findings suggests that people who suffer from BPD may be more susceptible to confusing dream content with actual waking events. PMID:26441768
NASA Astrophysics Data System (ADS)
Flynn, Lawrence E.; Labow, Gordon J.; Beach, Robert A.; Rawlins, Michael A.; Flittner, David E.
1996-10-01
Inexpensive devices to measure solar UV irradiance are available to monitor atmospheric ozone, for example, total ozone portable spectroradiometers (TOPS instruments). A procedure to convert these measurements into ozone estimates is examined. For well-characterized filters with 7-nm FWHM bandpasses, the method provides ozone values (from 304- and 310-nm channels) with less than 0.4 error attributable to inversion of the theoretical model. Analysis of sensitivity to model assumptions and parameters yields estimates of 3 bias in total ozone results with dependence on total ozone and path length. Unmodeled effects of atmospheric constituents and instrument components can result in additional 2 errors.
Theoretical conformational analysis of the bovine adrenal medulla 12 residue peptide molecule
NASA Astrophysics Data System (ADS)
Akhmedov, N. A.; Tagiyev, Z. H.; Hasanov, E. M.; Akverdieva, G. A.
2003-02-01
The spatial structure and conformational properties of the bovine adrenal medulla 12 residue peptide Tyr1-Gly2-Gly3-Phe4-Met5-Arg6-Arg7-Val8-Gly9-Arg10-Pro11-Glu12 (BAM-12P) molecule were studied by theoretical conformational analysis. It is revealed that this molecule can exist in several stable states. The energy and geometrical parameters for the low-energy conformations are obtained. The conformationally rigid and labile segments of this molecule were revealed.
NASA Astrophysics Data System (ADS)
Gromalova, N. A.; Eremin, N. N.; Dorokhova, G. I.; Urusov, V. S.
2012-07-01
A morphological analysis of chrysoberyl and alexandrite crystals obtained by flux crystallization has been performed. Seven morphological types of crystals are selected. The surface energies of the faces of chrysoberyl and alexandrite crystals and their isostructural analogs, BeCr2O4 and BeFe2O4, have been calculated by atomistic computer modeling using the Metadise program. A "combined" approach is proposed which takes into account both the structural geometry and the surface energy of the faces and thus provides better agreement between the theoretical and experimentally observed faceting of chrysoberyl and alexandrite crystals.
Theoretical free vibration analysis of rectangular cantilever plates with rigid point supports
NASA Astrophysics Data System (ADS)
Saliba, H. T.
1993-07-01
The practical engineering problem of cantilever plates with rigid point supports is dealt with in this paper. A highly accurate, economical and practical solution is outlined for the transverse free vibration analysis of these plates. The accuracy of the solution is discussed. It is also shown how well the solution lends itself to the optimization of point support locations. Numerical results are compared with experimental values to show the excellent agreement between the two sets of results. Examples of experimental and theoretical mode shapes are also provided for a square cantilever plate with four rigid point supports. Excellent agreement is observed here as well.
NASA Astrophysics Data System (ADS)
Lobach, I.; Benediktovitch, A.
2016-07-01
The possibility of quantitative texture analysis by means of parametric x-ray radiation (PXR) from relativistic electrons with Lorentz factor γ > 50MeV in a polycrystal is considered theoretically. In the case of rather smooth orientation distribution function (ODF) and large detector (θD >> 1/γ) the universal relation between ODF and intensity distribution is presented. It is shown that if ODF is independent on one from Euler angles, then the texture is fully determined by angular intensity distribution. Application of the method to the simulated data shows the stability of the proposed algorithm.
Insulin-dependent diabetes mellitus and quality of life. A theoretical analysis.
Hanestad, B R
1989-01-01
Insulin-dependent diabetes mellitus (IDDM) affects the overall life situation of the individual. The term "quality of life" means each individual person's estimation of what it means to have a good life. There are many aspects of diabetes which will influence to a greater or lesser extent each individual's degree of satisfaction with his/her life. This theoretical analysis shows that there is no direct connection between reduced quality of life and IDDM. There is a need, however, for empirical investigations which will provide a better understanding of the relationship between quality of life and IDDM. PMID:2814081
Analysis of poetic literature using B. F. Skinner's theoretical framework from verbal behavior
Luke, Nicole M.
2003-01-01
This paper examines Skinner's work on verbal behavior in the context of literature as a particular class of written verbal behavior. It looks at contemporary literary theory and analysis and the contributions that Skinner's theoretical framework can make. Two diverse examples of poetic literature are chosen and analyzed following Skinner's framework, examining the dynamic interplay between the writer and reader that take place within the bounds of the work presented. It is concluded that Skinner's hypotheses about verbal behavior and the functional approach to understanding it have much to offer literary theorists in their efforts to understand literary works and should be more carefully examined.
PLANS: A finite element program for nonlinear analysis of structures. Volume 1: Theoretical manual
NASA Technical Reports Server (NTRS)
Pifko, A.; Levine, H. S.; Armen, H., Jr.
1975-01-01
The PLANS system is described which is a finite element program for nonlinear analysis. The system represents a collection of special purpose computer programs each associated with a distinct physical problem class. Modules of PLANS specifically referenced and described in detail include: (1) REVBY, for the plastic analysis of bodies of revolution; (2) OUT-OF-PLANE, for the plastic analysis of 3-D built-up structures where membrane effects are predominant; (3) BEND, for the plastic analysis of built-up structures where bending and membrane effects are significant; (4) HEX, for the 3-D elastic-plastic analysis of general solids; and (5) OUT-OF-PLANE-MG, for material and geometrically nonlinear analysis of built-up structures. The SATELLITE program for data debugging and plotting of input geometries is also described. The theoretical foundations upon which the analysis is based are presented. Discussed are the form of the governing equations, the methods of solution, plasticity theories available, a general system description and flow of the programs, and the elements available for use.
Survey and analysis of simple sequence repeats (SSRs) in three genomes of Candida species.
Jia, Dongmei
2016-06-15
Simple sequence repeats (SSRs) or microsatellites, which composed of tandem repeated short units of 1-6bp, have been paying attention continuously. Here, the distribution, composition and polymorphism of microsatellites and compound microsatellites were analyzed in three available genomes of Candida species (Candida dubliniensis, Candida glabrata and Candida orthopsilosis). The results show that there were 118,047, 66,259 and 61,119 microsatellites in genomes of C. dubliniensis, C. glabrata and C. orthopsilosis, respectively. The SSRs covered more than 1/3 length of genomes in the three species. The microsatellites, which just consist of bases A and (or) T, such as (A)n, (T)n, (AT)n, (TA)n, (AAT)n, (TAA)n, (TTA)n, (ATA)n, (ATT)n and (TAT)n, were predominant in the three genomes. The length of microsatellites was focused on 6bp and 9bp either in the three genomes or in its coding sequences. What's more, the relative abundance (19.89/kbp) and relative density (167.87bp/kbp) of SSRs in sequence of mitochondrion of C. glabrata were significantly great than that in any one of genomes or chromosomes of the three species. In addition, the distance between any two adjacent microsatellites was an important factor to influence the formation of compound microsatellites. The analysis may be helpful for further studying the roles of microsatellites in genomes' origination, organization and evolution of Candida species. PMID:26883055
Yuan, C Y; Zhang, C; Wang, P; Hu, S; Chang, H P; Xiao, W J; Lu, X T; Jiang, S B; Ye, J Z; Guo, X H
2014-01-01
Okra (Abelmoschus esculentus L.) is not only a nutrient-rich vegetable but also an important medicinal herb. Inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and differentiation of 24 okra genotypes. In this study, the PCR products were separated by electrophoresis on 8% nondenaturing polyacrylamide gel and visualized by silver staining. The 22 ISSR primers produced 289 amplified DNA fragments, and 145 (50%) fragments were polymorphic. The 289 markers were used to construct the dendrogram based on the unweighted pair-group method with arithmetic average (UPGMA) cluster analysis. The dendrogram indicated that 24 okras were clustered into 4 geographically distinct groups. The average polymorphism information content (PIC) was 0.531929, which showed that the majority of primers were informative. The high values of allele frequency, genetic diversity, and heterozygosity showed that primer-sample combinations produced measurable fragments. The mean distances ranged from 0.045455 to 0.454545. The dendrogram indicated that the ISSR markers succeeded in distinguishing most of the 24 varieties in relation to their genetic backgrounds and geographical origins. PMID:24841648
Chen, Pei-Yen; Yangi, Hsueh-Hui; Zen, Jyh-Myng; Shih, Ying
2011-01-01
A flow injection analysis coupled with electrochemical detection at an activated barrel plating nickel electrode (Ni-BPE) was developed as a sensitive, simple, and low-cost formaldehyde sensor. The mechanism of Ni-BPE toward the electrocatalytic oxidation of formaldehyde in alkaline medium at ambient temperature was proposed to be based on the electrocatalytic oxidation of formaldehyde by Ni(III)O(OH) species. Under the optimized conditions (flow rate = 1.2 mL/min; detection potential = +0.5 V versus Ag/AgCl), a good linearity in the window of 0.037 to 10 microg/mL formaldehyde was observed, and the LOD of 0.23 microg/L was calculated. The RSDs of intraday (n = 10) and interday (n = 6) replicate measurements of 0.185-5 microg/mL formaldehyde ranged from 1.45 to 3.60%, indicating good reproducibility of the proposed method. The proposed method was successfully applied to the determination of formaldehyde in commercial nail polish samples and a drinking water sample. PMID:22165025
The beauty of simple adaptive control and new developments in nonlinear systems stability analysis
Barkana, Itzhak
2014-12-10
Although various adaptive control techniques have been around for a long time and in spite of successful proofs of stability and even successful demonstrations of performance, the eventual use of adaptive control methodologies in practical real world systems has met a rather strong resistance from practitioners and has remained limited. Apparently, it is difficult to guarantee or even understand the conditions that can guarantee stable operations of adaptive control systems under realistic operational environments. Besides, it is difficult to measure the robustness of adaptive control system stability and allow it to be compared with the common and widely used measure of phase margin and gain margin that is utilized by present, mainly LTI, controllers. Furthermore, customary stability analysis methods seem to imply that the mere stability of adaptive systems may be adversely affected by any tiny deviation from the pretty idealistic and assumably required stability conditions. This paper first revisits the fundamental qualities of customary direct adaptive control methodologies, in particular the classical Model Reference Adaptive Control, and shows that some of their basic drawbacks have been addressed and eliminated within the so-called Simple Adaptive Control methodology. Moreover, recent developments in the stability analysis methods of nonlinear systems show that prior conditions that were customarily assumed to be needed for stability are only apparent and can be eliminated. As a result, sufficient conditions that guarantee stability are clearly stated and lead to similarly clear proofs of stability. As many real-world applications show, once robust stability of the adaptive systems can be guaranteed, the added value of using Add-On Adaptive Control along with classical Control design techniques is pushing the desired performance beyond any previous limits.
The beauty of simple adaptive control and new developments in nonlinear systems stability analysis
NASA Astrophysics Data System (ADS)
Barkana, Itzhak
2014-12-01
Although various adaptive control techniques have been around for a long time and in spite of successful proofs of stability and even successful demonstrations of performance, the eventual use of adaptive control methodologies in practical real world systems has met a rather strong resistance from practitioners and has remained limited. Apparently, it is difficult to guarantee or even understand the conditions that can guarantee stable operations of adaptive control systems under realistic operational environments. Besides, it is difficult to measure the robustness of adaptive control system stability and allow it to be compared with the common and widely used measure of phase margin and gain margin that is utilized by present, mainly LTI, controllers. Furthermore, customary stability analysis methods seem to imply that the mere stability of adaptive systems may be adversely affected by any tiny deviation from the pretty idealistic and assumably required stability conditions. This paper first revisits the fundamental qualities of customary direct adaptive control methodologies, in particular the classical Model Reference Adaptive Control, and shows that some of their basic drawbacks have been addressed and eliminated within the so-called Simple Adaptive Control methodology. Moreover, recent developments in the stability analysis methods of nonlinear systems show that prior conditions that were customarily assumed to be needed for stability are only apparent and can be eliminated. As a result, sufficient conditions that guarantee stability are clearly stated and lead to similarly clear proofs of stability. As many real-world applications show, once robust stability of the adaptive systems can be guaranteed, the added value of using Add-On Adaptive Control along with classical Control design techniques is pushing the desired performance beyond any previous limits.
Casares, Federico M.
2016-01-01
Background Comparative DNA microarray analyses typically yield very large gene expression data sets that reflect complex patterns of change. Despite the wealth of information that is obtained, the identification of stable reference genes is required for normalization of disease- or drug-induced changes across tested groups. This is a prerequisite in quantitative real-time reverse transcription-PCR (qRT-PCR) and relative RT-PCR but rare in gene microarray analysis. The goal of the present study was to outline a simple method for identification of reliable reference genes derived from DNA microarray data sets by comparative statistical analysis of software-generated and manually calculated candidate genes. Material/Methods DNA microarray data sets derived from whole-blood samples obtained from 14 Zucker diabetic fatty (ZDF) rats (7 lean and 7 diabetic obese) were used for the method development. This involved the use of software-generated filtering parameters to accomplish the desired signal-to-noise ratios, 75th percentile signal manual normalizations, and the selection of reference genes as endogenous controls for target gene expression normalization. Results The combination of software-generated and manual normalization methods yielded a group of 5 stably expressed, suitable endogenous control genes which can be used in further target gene expression determinations in whole blood of ZDF rats. Conclusions This method can be used to correct for potentially false results and aid in the selection of suitable endogenous control genes. It is especially useful when aimed to aid the software in cases of borderline results, where the expression and/or the fold change values are just beyond the pre-established set of acceptable parameters. PMID:27122237
NASA Astrophysics Data System (ADS)
Dasgupta, Sambarta
Transient stability and sensitivity analysis of power systems are problems of enormous academic and practical interest. These classical problems have received renewed interest, because of the advancement in sensor technology in the form of phasor measurement units (PMUs). The advancement in sensor technology has provided unique opportunity for the development of real-time stability monitoring and sensitivity analysis tools. Transient stability problem in power system is inherently a problem of stability analysis of the non-equilibrium dynamics, because for a short time period following a fault or disturbance the system trajectory moves away from the equilibrium point. The real-time stability decision has to be made over this short time period. However, the existing stability definitions and hence analysis tools for transient stability are asymptotic in nature. In this thesis, we discover theoretical foundations for the short-term transient stability analysis of power systems, based on the theory of normally hyperbolic invariant manifolds and finite time Lyapunov exponents, adopted from geometric theory of dynamical systems. The theory of normally hyperbolic surfaces allows us to characterize the rate of expansion and contraction of co-dimension one material surfaces in the phase space. The expansion and contraction rates of these material surfaces can be computed in finite time. We prove that the expansion and contraction rates can be used as finite time transient stability certificates. Furthermore, material surfaces with maximum expansion and contraction rate are identified with the stability boundaries. These stability boundaries are used for computation of stability margin. We have used the theoretical framework for the development of model-based and model-free real-time stability monitoring methods. Both the model-based and model-free approaches rely on the availability of high resolution time series data from the PMUs for stability prediction. The problem of
CAPTURING SUBJECT VARIABILITY IN FMRI DATA : A GRAPH-THEORETICAL ANALYSIS OF GICA VS. IVA
Laney, Jonathan; Westlake, Kelly; Ma, Sai; Woytowicz, Elizabeth; Calhoun, Vince D.; Adalı, Tülay
2016-01-01
Background Recent studies using simulated functional magnetic resonance imaging (fMRI) data show that independent vector analysis (IVA) is a superior solution for capturing spatial subject variability when compared with the widely used group independent component analysis (GICA). Retaining such variability is of fundamental importance for identifying spatially localized group differences in intrinsic brain networks. New Methods Few studies on capturing subject variability and order selection have evaluated real fMRI data. Comparison of multivariate components generated by multiple algorithms is not straightforward. The main difficulties are finding concise methods to extract meaningful features and comparing multiple components despite lack of a ground truth. In this paper, we present a graph-theoretic approach to effectively compare the ability of multiple multivariate algorithms to capture subject variability for real fMRI data for effective group comparisons. Results Discriminating trends in features calculated from IVA- and GICA-generated components show that IVA better preserves the qualities of centrality and small worldness in fMRI data. IVA also produced components with more activated voxels leading to larger area under the curve (AUC) values. Comparison with Existing Method IVA is compared with widely used GICA for the purpose of group discrimination in terms of graph-theoretic features. In addition, masks are applied for motor related components generated by both algorithms. Conclusions Results show IVA better captures subject variability producing more activated voxels and generating components with less mutual information in the spatial domain than Group ICA. IVA-generated components result in smaller p-values and clearer trends in graph-theoretic features. PMID:25797843
Ghosh, Sourish; Kumar, G. Vinodh; Basu, Anirban; Banerjee, Arpan
2015-01-01
Complex protein networks underlie any cellular function. Certain proteins play a pivotal role in many network configurations, disruption of whose expression proves fatal to the cell. An efficient method to tease out such key proteins in a network is still unavailable. Here, we used graph-theoretic measures on protein-protein interaction data (interactome) to extract biophysically relevant information about individual protein regulation and network properties such as formation of function specific modules (sub-networks) of proteins. We took 5 major proteins that are involved in neuronal apoptosis post Chandipura Virus (CHPV) infection as seed proteins in a database to create a meta-network of immediately interacting proteins (1st order network). Graph theoretic measures were employed to rank the proteins in terms of their connectivity and the degree upto which they can be organized into smaller modules (hubs). We repeated the analysis on 2nd order interactome that includes proteins connected directly with proteins of 1st order. FADD and Casp-3 were connected maximally to other proteins in both analyses, thus indicating their importance in neuronal apoptosis. Thus, our analysis provides a blueprint for the detection and validation of protein networks disrupted by viral infections. PMID:26404759
Group theoretical analysis of the H3+ +H2 ↔ H5+ reaction
NASA Astrophysics Data System (ADS)
Lin, Zhou
2016-06-01
The H3+ +H2 →H2 + H3+ proton transfer reaction is complicated due to the proton scrambling from the large amplitude motions in the H5+ intermediate. In order to understand this reaction, high-resolution spectroscopic studies are necessary for the reactants/products and the intermediate, and the group theoretical analysis is an essential aspect in the prediction and interpretation of these spectra. With five indistinguishable protons, H5+ is characterized using the G240 complete nuclear permutation-inversion (CNPI) group. For most of the configurations sampled by the reaction path, the feasible permutations depend on the distance between the H3+ and H2 fragments. Subgroups of G240 can be used to describe these feasible permutations. Specifically, we consider two limits of the molecular configurations. The equilibrium structure of H5+ , i.e., [H2 -H -H2 ]+, can be described using the G16 molecular symmetry group, while the dissociation products, i.e., H3+ ⋯H2 , require the G24 molecular symmetry group. In the present study, a group theoretical analysis is performed for both limits, providing the symmetries for the nuclear spins and rovibrational wave functions. Also, spectroscopic properties for [H2 -H -H2 ]+, particularly rovibrational couplings and electric dipole selection rules, as well as correlations of energy levels between [H2 -H -H2 ]+ and H3+ ⋯H2 , are obtained.
Ghosh, Sourish; Kumar, G Vinodh; Basu, Anirban; Banerjee, Arpan
2015-01-01
Complex protein networks underlie any cellular function. Certain proteins play a pivotal role in many network configurations, disruption of whose expression proves fatal to the cell. An efficient method to tease out such key proteins in a network is still unavailable. Here, we used graph-theoretic measures on protein-protein interaction data (interactome) to extract biophysically relevant information about individual protein regulation and network properties such as formation of function specific modules (sub-networks) of proteins. We took 5 major proteins that are involved in neuronal apoptosis post Chandipura Virus (CHPV) infection as seed proteins in a database to create a meta-network of immediately interacting proteins (1(st) order network). Graph theoretic measures were employed to rank the proteins in terms of their connectivity and the degree upto which they can be organized into smaller modules (hubs). We repeated the analysis on 2(nd) order interactome that includes proteins connected directly with proteins of 1(st) order. FADD and Casp-3 were connected maximally to other proteins in both analyses, thus indicating their importance in neuronal apoptosis. Thus, our analysis provides a blueprint for the detection and validation of protein networks disrupted by viral infections. PMID:26404759
Guye, Maxime; Bettus, Gaelle; Bartolomei, Fabrice; Cozzone, Patrick J
2010-12-01
Graph theoretical analysis of structural and functional connectivity MRI data (ie. diffusion tractography or cortical volume correlation and resting-state or task-related (effective) fMRI, respectively) has provided new measures of human brain organization in vivo. The most striking discovery is that the whole-brain network exhibits "small-world" properties shared with many other complex systems (social, technological, information, biological). This topology allows a high efficiency at different spatial and temporal scale with a very low wiring and energy cost. Its modular organization also allows for a high level of adaptation. In addition, degree distribution of brain networks demonstrates highly connected hubs that are crucial for the whole-network functioning. Many of these hubs have been identified in regions previously defined as belonging to the default-mode network (potentially explaining the high basal metabolism of this network) and the attentional networks. This could explain the crucial role of these hub regions in physiology (task-related fMRI data) as well as in pathophysiology. Indeed, such topological definition provides a reliable framework for predicting behavioral consequences of focal or multifocal lesions such as stroke, tumors or multiple sclerosis. It also brings new insights into a better understanding of pathophysiology of many neurological or psychiatric diseases affecting specific local or global brain networks such as epilepsy, Alzheimer's disease or schizophrenia. Graph theoretical analysis of connectivity MRI data provides an outstanding framework to merge anatomical and functional data in order to better understand brain pathologies. PMID:20349109
Detection of allosteric signal transmission by information-theoretic analysis of protein dynamics
Pandini, Alessandro; Fornili, Arianna; Fraternali, Franca; Kleinjung, Jens
2012-01-01
Allostery offers a highly specific way to modulate protein function. Therefore, understanding this mechanism is of increasing interest for protein science and drug discovery. However, allosteric signal transmission is difficult to detect experimentally and to model because it is often mediated by local structural changes propagating along multiple pathways. To address this, we developed a method to identify communication pathways by an information-theoretical analysis of molecular dynamics simulations. Signal propagation was described as information exchange through a network of correlated local motions, modeled as transitions between canonical states of protein fragments. The method was used to describe allostery in two-component regulatory systems. In particular, the transmission from the allosteric site to the signaling surface of the receiver domain NtrC was shown to be mediated by a layer of hub residues. The location of hubs preferentially connected to the allosteric site was found in close agreement with key residues experimentally identified as involved in the signal transmission. The comparison with the networks of the homologues CheY and FixJ highlighted similarities in their dynamics. In particular, we showed that a preorganized network of fragment connections between the allosteric and functional sites exists already in the inactive state of all three proteins.—Pandini, A., Fornili, A., Fraternali, F., Kleinjung, J. Detection of allosteric signal transmission by information-theoretic analysis of protein dynamics. PMID:22071506
Theoretical analysis of the microwave-drill near-field localized heating effect
NASA Astrophysics Data System (ADS)
Jerby, E.; Aktushev, O.; Dikhtyar, V.
2005-02-01
The microwave-drill principle [Jerby et al., Science 298, 587 (2002)] is based on a localized hot-spot effect induced by a near-field coaxial applicator. The microwave drill melts the nonmetallic material locally and penetrates mechanically into it to shape the hole. This paper presents a theoretical analysis of the thermal-runaway effect induced in front of the microwave drill. The model couples the Maxwell's and heat equations including the material's temperature-dependent properties. A finite-difference time-domain algorithm is applied in a two-time-scale numerical model. The simulation is demonstrated for mullite, and benchmarked in simplified cases. The results show a temperature rise of ˜103K/s up to 1300K within a hot spot confined to a ˜4-mm width (˜0.1 wavelength). The input-port response to this near-field effect is modeled by equivalent time-varying lumped-circuit elements. Besides the physical insight, this theoretical study provides computational tools for design and analysis of microwave drills and for their real-time monitoring and adaptive impedance matching.
NDARC-NASA Design and Analysis of Rotorcraft Theoretical Basis and Architecture
NASA Technical Reports Server (NTRS)
Johnson, Wayne
2010-01-01
The theoretical basis and architecture of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are described. The principal tasks of NDARC are to design (or size) a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated. The aircraft attributes are obtained from the sum of the component attributes. NDARC provides a capability to model general rotorcraft configurations, and estimate the performance and attributes of advanced rotor concepts. The software has been implemented with low-fidelity models, typical of the conceptual design environment. Incorporation of higher-fidelity models will be possible, as the architecture of the code accommodates configuration flexibility, a hierarchy of models, and ultimately multidisciplinary design, analysis and optimization.
Theoretical and computational analysis of flow oscillations in S-CO{sub 2} natural circulation loop
Smith, W. C.; Podowski, M. Z.
2012-07-01
The objective of this paper is to present a new model of natural-circulation loop cooled using fluids at slightly supercritical pressures. The modeling concept is based on the first principle time- and position-depended conservation equations, combined with analytic models of temperature and pressure-dependent fluid properties and a pressure control line connected to a pressurizer. Extensive parametric testing has been performed of the numerical solution method used in the analysis. The results of model predictions have been compared against other existing results, both theoretical and experimental. In particular, the model has been used in the analysis of a transient response of the SCO{sub 2} loop reported by Milone [1]. (authors)
A thematic analysis of theoretical models for translational science in nursing: mapping the field.
Mitchell, Sandra A; Fisher, Cheryl A; Hastings, Clare E; Silverman, Leanne B; Wallen, Gwenyth R
2010-01-01
The quantity and diversity of conceptual models in translational science may complicate rather than advance the use of theory. This paper offers a comparative thematic analysis of the models available to inform knowledge development, transfer, and utilization. Literature searches identified 47 models for knowledge translation. Four thematic areas emerged: (1) evidence-based practice and knowledge transformation processes, (2) strategic change to promote adoption of new knowledge, (3) knowledge exchange and synthesis for application and inquiry, and (4) designing and interpreting dissemination research. This analysis distinguishes the contributions made by leaders and researchers at each phase in the process of discovery, development, and service delivery. It also informs the selection of models to guide activities in knowledge translation. A flexible theoretical stance is essential to simultaneously develop new knowledge and accelerate the translation of that knowledge into practice behaviors and programs of care that support optimal patient outcomes. PMID:21074646
Dass, Amala; Theivendran, Shevanuja; Nimmala, Praneeth Reddy; Kumara, Chanaka; Jupally, Vijay Reddy; Fortunelli, Alessandro; Sementa, Luca; Barcaro, Giovanni; Zuo, Xiaobing; Noll, Bruce C.
2015-04-15
Crystal structure determination has revolutionized modern science in biology, chemistry, and physics. However, the difficulty in obtaining periodic crystal lattices which are needed for X-ray crystal analysis has hindered the determination of atomic structure in nanomaterials, known as the "nanostructure problem". Here, by using rigid and bulky ligands, we have overcome this limitation and successfully solved the X-ray crystallographic structure of the largest reported thiolated gold nanomolecule, Au133S52. The total composition, Au-133(SPh-tBu)(52), was verified using high resolution electrospray ionization mass spectrometry (ESI-MS). The experimental and simulated optical spectra show an emergent surface plasmon resonance that is more pronounced than in the slightly larger Au-144(SCH2CH2Ph)(60). Theoretical analysis indicates that the presence of rigid and bulky ligands is the key to the successful crystal formation.
NASA Astrophysics Data System (ADS)
Guoji, Shen; McLaughlin, Stephen; Yongcheng, Xu; White, Paul
2014-02-01
Condition monitoring and fault diagnosis is an important issue for gearbox maintenance and safety. The critical process involved in such activities is to extract reliable features representative of the condition of the gears or gearbox. In this paper a framework is presented for the application of bispectrum to the analysis of gearbox vibration. The bispectrum of a composite signal consisting of multiple periodic components has peaks at the bifrequencies that correspond to closely related components which can be produced by any nonlinearity. As a result, biphase verification is necessary to decrease false-alarming for any bispectrum-based method. A model based on modulated signals is adopted to reveal the bispectrum characteristics for the vibration of a faulty gear, and the corresponding amplitude and phase of the bispectrum expression are deduced. Therefore, a diagnostic approach based on the theoretical result is derived and verified by the analysis of a set of vibration signals from a helicopter gearbox.
Thio, Tzer Hwai Gilbert; Soroori, Salar; Ibrahim, Fatimah; Al-Faqheri, Wisam; Soin, Norhayati; Kulinsky, Lawrence; Madou, Marc
2013-05-01
This paper presents a theoretical development and critical analysis of the burst frequency equations for capillary valves on a microfluidic compact disc (CD) platform. This analysis includes background on passive capillary valves and the governing models/equations that have been developed to date. The implicit assumptions and limitations of these models are discussed. The fluid meniscus dynamics before bursting is broken up into a multi-stage model and a more accurate version of the burst frequency equation for the capillary valves is proposed. The modified equations are used to evaluate the effects of various CD design parameters such as the hydraulic diameter, the height to width aspect ratio, and the opening wedge angle of the channel on the burst pressure. PMID:23292292
A Thematic Analysis of Theoretical Models for Translational Science in Nursing: Mapping the Field
Mitchell, Sandra A.; Fisher, Cheryl A.; Hastings, Clare E.; Silverman, Leanne B.; Wallen, Gwenyth R.
2010-01-01
Background The quantity and diversity of conceptual models in translational science may complicate rather than advance the use of theory. Purpose This paper offers a comparative thematic analysis of the models available to inform knowledge development, transfer, and utilization. Method Literature searches identified 47 models for knowledge translation. Four thematic areas emerged: (1) evidence-based practice and knowledge transformation processes; (2) strategic change to promote adoption of new knowledge; (3) knowledge exchange and synthesis for application and inquiry; (4) designing and interpreting dissemination research. Discussion This analysis distinguishes the contributions made by leaders and researchers at each phase in the process of discovery, development, and service delivery. It also informs the selection of models to guide activities in knowledge translation. Conclusions A flexible theoretical stance is essential to simultaneously develop new knowledge and accelerate the translation of that knowledge into practice behaviors and programs of care that support optimal patient outcomes. PMID:21074646
A theoretical analysis of pitch stability during gliding in flying snakes.
Jafari, Farid; Ross, Shane D; Vlachos, Pavlos P; Socha, John J
2014-06-01
Flying snakes use their entire body as a continuously morphing 'wing' to produce lift and shallow their glide trajectory. Their dominant behavior during gliding is aerial undulation, in which lateral waves are sent posteriorly down the body. This highly dynamic behavior, which is unique among animal gliders, should have substantial effects on the flight dynamics and stability of the snakes, resulting from the continuous redistribution of mass and aerodynamic forces. In this study, we develop two-dimensional theoretical models to assess the stability characteristics of snakes in the pitch direction. Previously measured force coefficients are used to simulate aerodynamic forces acting on the models, and undulation is simulated by varying mass. Model 1 is a simple three-airfoil representation of the snake's body that possesses a passively stable equilibrium solution, whose basin of stability contains initial conditions observed in experimental gliding trajectories. Model 2 is more sophisticated, with more degrees of freedom allowing for postural changes to better represent the snake's real kinematics; in addition, a restoring moment is added to simulate potential active control. The application of static and dynamic stability criteria show that Model 2 is passively unstable, but can be stabilized with a restoring moment. Overall, these models suggest that undulation does not contribute to stability in pitch, and that flying snakes require a closed-loop control system formed around a passively stable dynamical framework. PMID:24852642
ERIC Educational Resources Information Center
Braimoh, Dele
1994-01-01
A theoretical conceptualization of training needs assessment is developed using the example of distance education of paramedical personnel (nurses) in the developing countries of Africa. Accurate training needs analysis and a baseline survey are essential for program development. (SLD)
Wang, Y H; Zhang, X J; Fan, S J
2015-01-01
Annual wild soybean (Glycine soja Sieb. et Zucc.), the ancestor of cultivated soybean (G. max), is believed to be a potential gene source for further improvement of soybean to cope with environmental stress. In this study, 10 simple sequence repeat (SSR) markers were used to evaluate the genetic diversity and population genetic structure in five wild soybean populations using 195 accessions collected from Dongying, China. Ten SSR markers yielded 90 bands, with an average of nine bands per marker. The percentage of polymorphic loci (P) was 97.78%, the distribution of expected heterozygosity (HE) was 0.1994-0.4460 with an average of 0.3262, and the distribution from Shannon's information index (I) was 0.3595-0.6506 with an average of 0.5386. The results showed that wild soybean had a high degree of genetic diversity at the species level. Nei's differentiation coefficient (FST) was 0.1533, and gene flow (Nm) was 1.3805, which indicated that genetic variation mainly existed within populations and that there was a certain level of gene exchange between populations. Some genetic differentiation occurred among populations, although this was not significant. Cluster analysis indicated that there was no significant correlation between the genetic structure of wild soybean populations and their geographic distribution, and the clustering results may be relatively consistent with the habitats of the accessions. In the present study, the genetic diversity of wild soybeans showed a broad genetic base and enables suggestions for the conservation of this plant to be made. PMID:26436402
Theoretical Analysis of Triple Liquid Stub Tuner Impedance Matching for ICRH on Tokamaks
NASA Astrophysics Data System (ADS)
Du, Dan; Gong, Xueyu; Yin, Lan; Xiang, Dong; Li, Jingchun
2015-12-01
The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating (ICRH) antennae with high power injection into plasmas. A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors. This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions. The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution. Then, the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions. The method provides an alternative theoretical method, rather than measurements, to study triple liquid stub tuner impedance matching for ICRH, which may be beneficial for the design of ICRH systems on tokamaks. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2014GB108002, 2013GB107001), National Natural Science Foundation of China (Nos. 11205086, 11205053, 11375085, and 11405082), the Construct Program of Fusion and Plasma Physics Innovation Team in Hunan Province, China (No. NHXTD03), the Natural Science Foundation of Hunan Province, China (No. 2015JJ4044)
Recent theoretical advances in analysis of AIRS/AMSU sounding data
NASA Astrophysics Data System (ADS)
Susskind, Joel
2007-04-01
The AIRS Science Team Version 5.0 retrieval algorithm will become operational at the Goddard DAAC in early 2007 in the near real-time analysis of AIRS/AMSU sounding data. This algorithm contains many significant theoretical advances over the AIRS Science Team Version 4.0 retrieval algorithm used previously. Three very significant developments are: 1) the development and implementation of a very accurate Radiative Transfer Algorithm (RTA) which allows for accurate treatment of non-Local Thermodynamic Equilibrium (non-LTE) effects on shortwave sounding channels; 2) the development of methodology to obtain very accurate case by case product error estimates which are in turn used for quality control; and 3) development of an accurate AIRS only cloud clearing and retrieval system. These theoretical improvements taken together enabled a new methodology to be developed which further improves soundings in partially cloudy conditions, without the need for microwave observations in the cloud clearing step as has been done previously. In this methodology, longwave CO II channel observations in the spectral region 700 cm -1 to 750 cm -1 are used exclusively for cloud clearing purposes, while shortwave CO II channels in the spectral region 2195 cm -1 to 2395 cm -1 are used for temperature sounding purposes. The new methodology is described briefly and results are shown, including comparison with those using AIRS Version 4, as well as a forecast impact experiment assimilating AIRS Version 5.0 retrieval products in the Goddard GEOS 5 Data Assimilation System.
Theoretical Analysis of the Vibration of Axisymmetric Liquid Bridges of Arbitrary Shape
NASA Astrophysics Data System (ADS)
Montanero, J. M.
A liquid bridge consists of a mass of liquid sustained by the action of capillary forces between two parallel disks. The dynamics of these liquid columns has been extensively analysed both theoretically and experimentally over the last decades. Many of the studies have focused on the dynamical response of cylindrical liquid bridges subjected to the action of an oscillatory microgravity field due to, for instance, an in-phase vibration of the supporting disks. There have been fewer studies dealing with the vibration of axisymmetric liquid bridges of arbitrary shape. In this paper the dynamics of rotating inviscid axisymmetric liquid bridges is analysed considering the combined effect of residual gravity, the inequality of the disks and the liquid bridge volume. The results are calculated numerically by using the one-dimensional Cosserat model and the full three-dimensional description. The excitation is assumed to be of small amplitude and harmonic, so that the theoretical models are linearized and the analysis is performed in the frequency domain. The details of the numerical methods proposed are discussed. Comparison between the values of the first resonance frequency obtained from both models shows an excellent agreement for long liquid bridges, the discrepancies increasing as the value of the slenderness decreases.
Kumarasinghe, Chathurangi S; Premaratne, Malin; Gunapala, Sarath D; Agrawal, Govind P
2016-07-21
Metallic nanostructures under optical illumination can generate a non-equilibrium high-energy electron gas (also known as hot electrons) capable of being injected into neighbouring media over a potential barrier at particle boundaries. The nature of this process is highly nanoparticle shape and size dependent. Here, we have derived an analytical expression for the frequency dependent rate of injection of these energetic electrons from a metallic nanotube into a semiconductor layer in contact with its inner boundary. In our derivation, we have considered the quantum mechanical motion of the electron gas confined by the particle boundaries in determining the electron energy spectrum and wave functions. We present a comprehensive theoretical analysis of how different geometric parameters such as the outer to inner radius ratio, length and thickness of a nanotube and illumination frequency affect the hot electron injection and internal quantum efficiency of the nanotube. We reveal that longer nanotubes with thin shells and high inner to outer radius ratios show better performance at visible and infrared frequencies. Our derivations and results provide the much needed theoretical insight for optimization of thin nanotubes for different hot electron based applications. PMID:27332556
Kukla, Maija M.; Kotomin, Eugene Alexej; Merkle, R.; Mastrikov, Yuri; Maier, J.
2013-02-11
Solid oxide fuel cells (SOFC) are under intensive investigation since the 1980’s as these devices open the way for ecologically clean direct conversion of the chemical energy into electricity, avoiding the efficiency limitation by Carnot’s cycle for thermochemical conversion. However, the practical development of SOFC faces a number of unresolved fundamental problems, in particular concerning the kinetics of the electrode reactions, especially oxygen reduction reaction. We review recent experimental and theoretical achievements in the current understanding of the cathode performance by exploring and comparing mostly three materials: (La,Sr)MnO3 (LSM), (La,Sr)(Co,Fe)O3 (LSCF) and (Ba,Sr)(Co,Fe)O3 (BSCF). Special attention is paid to a critical evaluation of advantages and disadvantages of BSCF, which shows the best cathode kinetics known so far for oxides. We demonstrate that it is the combined experimental and theoretical analysis of all major elementary steps of the oxygen reduction reaction which allows us to predict the rate determining steps for a given material under specific operational conditions and thus control and improve SOFC performance.
Esquivel, Rodolfo O; Molina-Espíritu, Moyocoyani; López-Rosa, Sheila; Soriano-Correa, Catalina; Barrientos-Salcedo, Carolina; Kohout, Miroslav; Dehesa, Jesús S
2015-08-24
In this work we undertake a pioneer information-theoretical analysis of 18 selected amino acids extracted from a natural protein, bacteriorhodopsin (1C3W). The conformational structures of each amino acid are analyzed by use of various quantum chemistry methodologies at high levels of theory: HF, M062X and CISD(Full). The Shannon entropy, Fisher information and disequilibrium are determined to grasp the spatial spreading features of delocalizability, order and uniformity of the optimized structures. These three entropic measures uniquely characterize all amino acids through a predominant information-theoretic quality scheme (PIQS), which gathers all chemical families by means of three major spreading features: delocalization, narrowness and uniformity. This scheme recognizes four major chemical families: aliphatic (delocalized), aromatic (delocalized), electro-attractive (narrowed) and tiny (uniform). All chemical families recognized by the existing energy-based classifications are embraced by this entropic scheme. Finally, novel chemical patterns are shown in the information planes associated with the PIQS entropic measures. PMID:26175003
Seven methods for the analysis of simple cyanides have been investigated. Included are (1) an ion-exchange procedure, (2) a continuous-flow distillation, (3) and EDTA electrode method, (4) the American Iron and Steel Institute aeration method, (5) an EDTA aeration method, (6) the...
Theoretical analysis of electronic absorption spectra of vitamin B12 models
NASA Astrophysics Data System (ADS)
Andruniow, Tadeusz; Kozlowski, Pawel M.; Zgierski, Marek Z.
2001-10-01
Time-dependent density-functional theory (TD-DFT) is applied to analyze the electronic absorption spectra of vitamin B12. To accomplish this two model systems were considered: CN-[CoIII-corrin]-CN (dicyanocobinamide, DCC) and imidazole-[CoIII-corrin]-CN (cyanocobalamin, ImCC). For both models 30 lowest excited states were calculated together with transition dipole moments. When the results of TD-DFT calculations were directly compared with experiment it was found that the theoretical values systematically overestimate experimental data by approximately 0.5 eV. The uniform adjustment of the calculated transition energies allowed detailed analysis of electronic absorption spectra of vitamin B12 models. All absorption bands in spectral range 2.0-5.0 eV were readily assigned. In particular, TD-DFT calculations were able to explain the origin of the shift of the lowest absorption band caused by replacement of the-CN axial ligand by imidazole.
NASA Astrophysics Data System (ADS)
Kagawa, Noboru; Uematsu, Masahiko; Watanabe, Koichi
In recent years there has been an increasing interest of the use of nonazeotropic binary mixtures to improve performance in heat pump systems, and to restrict the consumption of chlorofluorocarbon (CFC) refrigerants as internationally agreed-upon in the Montreal Protocol. However, the available knowledge on the thermophysical properties of mixtures is very much limited particularly with respect to quantitative information. In order to systematize cycle performance with Refrigerant 12 (CCl2F2) + Refrigerant 22 (CHClF2) and Refrigerant 22 + Refrigerant 114 (CClF2-CClF2) systems which are technically important halogenated refrigerant mixtures, the heat pump cycle analysis in case of using these mixtures was theoretically studied. It became clear that the maximum coefficients of performance with various pure refrigerants and binary refrigerant mixtures were obtained at the reduced condensing temperature being 0.9 when the same temperature difference between condensing and evaporating temperature was chosen.
On the possibility of shear-driven chromatography: a theoretical performance analysis.
Desmet, G; Baron, G V
1999-09-01
The use of shear forces for the generation of the mobile phase flow in chromatographic separations is proposed. This novel chromatographic operating principle, referred to as shear-driven chromatography (SDC), completely circumvents the pressure-drop limitation of conventional pressure-driven GC and LC without affecting the operational flexibility (choice of mobile and stationary phases, possibility of solvent and/or temperature programming, etc.). In the present paper, the expression for the height equivalent to a theoretical plate in SDC in a channel with a flat rectangular cross-section is established and is used to demonstrate the large gain in analysis speed under LC, GC and supercritical fluid chromatography conditions. PMID:10514973
Sugimura, A; Zakharov, A V
2011-08-01
The peculiarities in the dynamic of the director reorientation in a liquid crystal (LC) film under the influence of the electric E field directed at an angle α to the magnetic B field have been investigated both experimentally and theoretically. Time-resolved deuterium NMR spectroscopy is employed to investigate the field-induced director dynamics. Analysis of the experimental results, based on the predictions of hydrodynamic theory including both the director motion and fluid flow, provides an evidence for the appearance of the spatially periodic patterns in 4-n-pentyl-4'-cyanobiphenyl LC film, at the angles α>60∘, in response to the suddenly applied E. These periodic distortions produce a lower effective rotational viscosity. This gives a faster response of the director rotation than for a uniform mode, as observed in our NMR experiment. PMID:21929001
NASA Astrophysics Data System (ADS)
Zhang, Man-Gong; Cao, Yan-Ping; Li, Guo-Yang; Feng, Xi-Qiao
2014-08-01
This paper explores the pipette aspiration test of hyperelastic compliant materials. Explicit expressions of the relationship between the imposed pressure and the aspiration length are developed, which serve as fundamental relations to deduce the material parameters from experimental responses. Four commonly used hyperelastic constitutive models, e.g. neo-Hookean, Mooney-Rivlin, Fung, and Arruda-Boyce models, are investigated. Through dimensional analysis and nonlinear finite element simulations, we establish the relations between the experimental responses and the constitutive parameters of hyperelastic materials in explicit form, upon which inverse approaches for determining the hyperelastic properties of materials are developed. The reliability of the results given by the proposed methods has been verified both theoretically and numerically. Experiments have been carried out on an elastomer (polydimethylsiloxane, 1:50) and porcine liver to validate the applicability of the inverse approaches in practical measurements.
Theoretical analysis on shear-bending deflection of a ring-shape piezoelectric plate
NASA Astrophysics Data System (ADS)
Yu, Zejun; Dong, Shuxiang; Fang, Daining
2016-02-01
In this paper, the electromechanical coupling field in shear-bending mode for a ring-shape piezoelectric plate was theoretically established. According to the classical small bending elastic plate theory and piezoelectric constitutive equations, the analytical solution to the bending deformation of the piezo-actuator under electric field and a concentrated or uniformly distributed mechanical load was achieved. The mechanism for generating bending deformation is attributed to axisymmetric shear strain, which further induces the bending deformation of the single ring-shape piezoelectric plate. This mechanism is significant different from that of piezoelectric bimorph or unimorph actuators reported before. Our analysis offers guidance for the optimum design of a ring-shape shear-bending piezo-actuator.
NASA Astrophysics Data System (ADS)
Dirba, I.; Kleperis, J.
2011-01-01
Analytical and numerical modelling is performed for the linear actuator of a parallel path magnet motor. In the model based on finite-element analysis, the 3D problem is reduced to a 2D problem, which is sufficiently precise in a design aspect and allows modelling the principle of a parallel path motor. The paper also describes a relevant numerical model and gives comparison with experimental results. The numerical model includes all geometrical and physical characteristics of the motor components. The magnetic flux density and magnetic force are simulated using FEMM 4.2 software. An experimental model has also been developed and verified for the core of switchable magnetic flux linear actuator and motor. The results of experiments are compared with those of theoretical/analytical and numerical modelling.
Germain, Ph
2010-07-28
We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties-the specific heat and the low shear viscosity-which incorporate contributions from the two components of the binary mixture. PMID:20687684
NASA Astrophysics Data System (ADS)
Germain, Ph.
2010-07-01
We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties—the specific heat and the low shear viscosity—which incorporate contributions from the two components of the binary mixture.
Shafii, Mohammad Ali Meidianti, Rahma Wildian, Fitriyani, Dian; Tongkukut, Seni H. J.; Arkundato, Artoto
2014-09-30
Theoretical analysis of integral neutron transport equation using collision probability (CP) method with quadratic flux approach has been carried out. In general, the solution of the neutron transport using the CP method is performed with the flat flux approach. In this research, the CP method is implemented in the cylindrical nuclear fuel cell with the spatial of mesh being conducted into non flat flux approach. It means that the neutron flux at any point in the nuclear fuel cell are considered different each other followed the distribution pattern of quadratic flux. The result is presented here in the form of quadratic flux that is better understanding of the real condition in the cell calculation and as a starting point to be applied in computational calculation.
Sebai, Jihane
2016-01-01
Various organizational, functional or structural issues have led to a review of the foundations of the former health care system based on a traditional market segmentation between general practice and hospital medicine, and between health and social sectors and marked by competition between private and public sectors. The current reconfiguration of the health care system has resulted in “new” levers explained by the development of a new organizational reconfiguration of the primary health care model. Coordinated care structures (SSC) have been developed in this context by making coordination the cornerstone of relations between professionals to ensure global, continuous and quality health care. This article highlights the contributions of various theoretical approaches to the understanding of the concept of coordination in the analysis of the current specificity of health care. PMID:27392057
Theoretical analysis of rotating two phase detonation in a rocket motor
NASA Technical Reports Server (NTRS)
Shen, I.; Adamson, T. C., Jr.
1973-01-01
Tangential mode, non-linear wave motion in a liquid propellant rocket engine is studied, using a two phase detonation wave as the reaction model. Because the detonation wave is followed immediately by expansion waves, due to the side relief in the axial direction, it is a Chapman-Jouguet wave. The strength of this wave, which may be characterized by the pressure ratio across the wave, as well as the wave speed and the local wave Mach number, are related to design parameters such as the contraction ratio, chamber speed of sound, chamber diameter, propellant injection density and velocity, and the specific heat ratio of the burned gases. In addition, the distribution of flow properties along the injector face can be computed. Numerical calculations show favorable comparison with experimental findings. Finally, the effects of drop size are discussed and a simple criterion is found to set the lower limit of validity of this strong wave analysis.
Vojniković, Bozo; Gabrić, Nikica; Dekaris, Iva
2013-04-01
The authors discussed about the problem of special form in astigmatism classification. This special type of astigmatism is the form of obliquely crossed astigmatism. In which the meridians, major and minor, are not right angles. In this astigmatism is not possible to prescribing for cylindrical (toric) spectacle lens. Authors describe the Thompson formula for oblique crossed cylinder and observe that this formula is to complicate for calculation new cylinder power. In this reason, the authors create the new formula and simple procedure for this calculation. This simple formula based on vector analysis and read: DM3 = DM2 x cos2 beta. PMID:23841133
Theoretical analysis of selectivity mechanisms in molecular transport through channels and nanopores
NASA Astrophysics Data System (ADS)
Agah, Shaghayegh; Pasquali, Matteo; Kolomeisky, Anatoly B.
2015-01-01
Selectivity is one of the most fundamental concepts in natural sciences, and it is also critically important in various technological, industrial, and medical applications. Although there are many experimental methods that allow to separate molecules, frequently they are expensive and not efficient. Recently, a new method of separation of chemical mixtures based on utilization of channels and nanopores has been proposed and successfully tested in several systems. However, mechanisms of selectivity in the molecular transport during the translocation are still not well understood. Here, we develop a simple theoretical approach to explain the origin of selectivity in molecular fluxes through channels. Our method utilizes discrete-state stochastic models that take into account all relevant chemical transitions and can be solved analytically. More specifically, we analyze channels with one and two binding sites employed for separating mixtures of two types of molecules. The effects of the symmetry and the strength of the molecular-pore interactions are examined. It is found that for one-site binding channels, the differences in the strength of interactions for two species drive the separation. At the same time, in more realistic two-site systems, the symmetry of interaction potential becomes also important. The most efficient separation is predicted when the specific binding site is located near the entrance to the nanopore. In addition, the selectivity is higher for large entrance rates into the channel. It is also found that the molecular transport is more selective for repulsive interactions than for attractive interactions. The physical-chemical origin of the observed phenomena is discussed.
Theoretical analysis of selectivity mechanisms in molecular transport through channels and nanopores
Agah, Shaghayegh; Pasquali, Matteo; Kolomeisky, Anatoly B.
2015-01-28
Selectivity is one of the most fundamental concepts in natural sciences, and it is also critically important in various technological, industrial, and medical applications. Although there are many experimental methods that allow to separate molecules, frequently they are expensive and not efficient. Recently, a new method of separation of chemical mixtures based on utilization of channels and nanopores has been proposed and successfully tested in several systems. However, mechanisms of selectivity in the molecular transport during the translocation are still not well understood. Here, we develop a simple theoretical approach to explain the origin of selectivity in molecular fluxes through channels. Our method utilizes discrete-state stochastic models that take into account all relevant chemical transitions and can be solved analytically. More specifically, we analyze channels with one and two binding sites employed for separating mixtures of two types of molecules. The effects of the symmetry and the strength of the molecular-pore interactions are examined. It is found that for one-site binding channels, the differences in the strength of interactions for two species drive the separation. At the same time, in more realistic two-site systems, the symmetry of interaction potential becomes also important. The most efficient separation is predicted when the specific binding site is located near the entrance to the nanopore. In addition, the selectivity is higher for large entrance rates into the channel. It is also found that the molecular transport is more selective for repulsive interactions than for attractive interactions. The physical-chemical origin of the observed phenomena is discussed.
NASA Astrophysics Data System (ADS)
Virkar, Anil V.
1991-05-01
Theoretical analysis of solid oxide fuel cells (SOFCs) using two-layer, composite electrolytes consisting of a solid electrolyte of a significantly higher conductivity compared to zirconia (such as ceria or bismuth oxide) with a thin layer of zirconia or thoria on the fuel side is presented. Electrochemical transport in the two-layer composite electrolytes is examined by taking both ionic and electronic fluxes into account. Similar to most electrochemical transport phenomena, it is assumed that local equilibrium prevails. An equivalent circuit approach is used to estimate the partial pressure of oxygen at the interface. It is shown that thermodynamic stability of the electrolyte (ceria or bismuth oxide) depends upon the transport characteristics of the composite electrolyte, in particular the electronic conductivity of the air-side part of the electrolyte. The analysis shows that it would be advantageous to use composite electrolytes instead of all-zirconia electrolytes, thus making low-temperature (about 600-800 C) SOFCs feasible. Implications of the analysis from the standpoint of the desired characteristics of SOFC components are discussed.
Data Analysis and Theoretical Studies of the Upper Mesosphere and Lower Thermosphere
NASA Technical Reports Server (NTRS)
Burns, Alan; Killeen, Timothy L.
1996-01-01
Three separate tasks were proposed under this award. The first involved extending our continuing study of electrodynamical feedback between the thermosphere/ionosphere and the magnetosphere. The second was a model-experiment comparison study of global dynamics and the third was a 'spectral energetics' analysis of tidal dissipation and energy exchange mechanisms. The Earth's mesosphere and lower-thermosphere/ionosphere (MLTI), between approximately 60 and 180 km altitude, is the most poorly understood region of the Earth's atmosphere, primarily because of its relative inaccessibility. This lack of knowledge has been widely recognized and has provided important scientific rationale for the upcoming NASA TIMED mission. While the data gathered during the TIMED era will revolutionize our understanding of the MLTI region, much work can be done prior to the mission, both to develop data-analysis and modeling techniques and to study the more limited relevant experimental data from previous missions. The grant reported on here continues and extends an existing successful program of scientific research into the energetics, dynamics and electrodynamics of the MLTI, using available theoretical and data analysis tools.
Error Analysis of Present Simple Tense in the Interlanguage of Adult Arab English Language Learners
ERIC Educational Resources Information Center
Muftah, Muneera; Rafik-Galea, Shameem
2013-01-01
The present study analyses errors on present simple tense among adult Arab English language learners. It focuses on the error on 3sg "-s" (the third person singular present tense agreement morpheme "-s"). The learners are undergraduate adult Arabic speakers learning English as a foreign language. The study gathered data from…
A Simple Empirical Analysis of the Enthalpies of Formation of Lanthanide Halides and Oxides.
ERIC Educational Resources Information Center
Smith, Derek W.
1986-01-01
Proposes a simple and general method whereby the lattice energies of lanthanide(II) and (IV) compounds are derived directly from those found experimentally for the corresponding lanthanide(III) compounds. The method is applicable to all lanthanide halides and oxides and involves calculations which can be easily and quickly performed by students.…
A simple and rapid method for the analysis of phenolic compounds in beverages and grains
Technology Transfer Automated Retrieval System (TEKTRAN)
A simple, rapid and direct method for detection of phenolics in foods and beverages is needed. The current standard method (Folin-Ciocalteau) indirectly measures the “total phenolics” through the reducing capacity of components of food or beverages. A novel method was developed to quantify polypheno...
Site-city interaction: theoretical, numerical and experimental crossed-analysis
NASA Astrophysics Data System (ADS)
Schwan, L.; Boutin, C.; Padrón, L. A.; Dietz, M. S.; Bard, P.-Y.; Taylor, C.
2016-05-01
The collective excitation of city structures by a seismic wavefield and the subsequent multiple Structure-Soil-Structure Interactions (SSSIs) between the buildings are usually disregarded in conventional seismology and earthquake engineering practice. The objective here is to qualify and quantify these complex multiple SSSIs through the design of an elementary study case, which serves as a benchmark for theoretical, numerical and experimental crossed-analysis. The experimental specimen consists of an idealized site-city setup with up to 37 anisotropic resonant structures arranged at the top surface of an elastic layer and in co-resonance with it. The experimental data from shaking table measurements is compared with the theoretical and numerical results provided respectively by an equivalent city-impedance model derived analytically from homogenization in the long-wavelength approximation and a model based on boundary elements. The signatures of the site-city interactions are identified in the frequency, time and space domain, and in particular consist of a frequency-dependent free/rigid switch in the surface condition at the city resonance, beatings in the records and the depolarization of the wavefield. A parametric study on the city density shows that multiple SSSIs among the city structures (five are sufficient) can have significant effects on both the seismic response of its implantation site and that of the buildings. Key parameters are provided to assess site-city interactions in the low seismic frequency range: They involve the mass and rigidity of the city compared to those of the soil and the damping of the building.
A theoretical and empirical analysis of context: neighbourhoods, smoking and youth.
Frohlich, Katherine L; Potvin, Louise; Chabot, Patrick; Corin, Ellen
2002-05-01
Numerous studies are currently addressing the issue of contextual effects on health and disease outcomes. The majority of these studies fall short of providing a theoretical basis with which to explain what context is and how it affects individual disease outcomes. We propose a theoretical model, entitled collective lifestyles, which brings together three concepts from practice theory: social structure, social practices and agency. We do so in an attempt to move away from both behavioural and structural-functionalist explanations of the differential distribution of disease outcomes among areas by including a contextualisation of health behaviours that considers their meaning. We test the framework using the empirical example of smoking and pre-adolescents in 32 communities across Québec, Canada. Social structure is operationalised as characteristics and resources; characteristics are the socio-economic aggregate characteristics of individuals culled from the 1996 Canadian Census, and resources are what regulates and transforms smoking practices. Information about social practices was collected in focus groups with pre-adolescents from four of the participating communities. Using zero-order and partial correlations we find that a portrait of communities emerges. Where there is a high proportion of more socio-economically advantaged people, resources tend to be more smoking discouraging, with the opposite being true for disadvantaged communities. Upon analysis of the focus group material, however, we find that the social practices in communities do not necessarily reflect the "objectified" measures of social structure. We suggest that a different conceptualisation of accessibility and lifestyle in contextual studies may enable us to improve our grasp on how differential rates of disease come about in local areas. PMID:12058856
Site-city interaction: Theoretical, numerical and experimental crossed-analysis
NASA Astrophysics Data System (ADS)
Schwan, L.; Boutin, C.; Padrón, L. A.; Dietz, M. S.; Bard, P.-Y.; Taylor, C.
2016-02-01
The collective excitation of city structures by a seismic wave-field and the subsequent multiple Structure-Soil-Structure Interactions (SSSI) between the buildings are usually disregarded in conventional seismology and earthquake engineering practice. The objective here is to qualify and quantify these complex multiple SSSI through the design of an elementary study case which serves as a benchmark for theoretical, numerical and experimental crossed-analysis. The experimental specimen consists of an idealized site-city setup with up to 37 anisotropic resonant structures arranged at the top surface of an elastic layer and in co-resonance with it. The experimental data from shaking table measurements is compared with the theoretical and numerical results provided respectively by: An equivalent city-impedance model derived analytically from homogenization in the long-wavelength approximation; and a model based on boundary elements. The signatures of the site-city interactions are identified in the frequency, time and space domain, and in particular consist of: A frequency-dependent free/rigid switch in the surface condition at the city resonance; beatings in the records; and the depolarization of the wave-field. A parametric study on the city density shows that multiple SSSI among the city structures (5 are sufficient) can have significant effects on both the seismic response of its implantation site and that of the buildings. Key parameters are provided to assess site-city interactions in the low seismic frequency range: They involve the mass and rigidity of the city compared to those of the soil and the damping of the building.
NASA Astrophysics Data System (ADS)
Kagawa, Noboru; Uematsu, Masahiko; Watanabe, Koichi
In recent years there has been an increasing interest of the use of nonazeotropic binary mixtures to improve performance in heat pump systems, and to restrict the consumption of chlorofluorocarbon (CFC) refrigerants as internationally agreed-upon in the Montreal Protocol. However, the available knowledge on the thermophysical properties of mixtures is very much limited particularly with respect to quantitative information. In order to examine cycle performance for Refrigerant 12 (CCl2F2) + Refrigerant 22 (CHClF2) and Refrigerant 22 + Refrigerant 114 (CClF2-CClF2) systems which are technically important halogenated refrigerant mixtures, the heat pump cycle analysis in case of using pure Refrigerants 12, 22 and 114 was theoretically carried out in the present paper. For the purpose of systematizing the heat pump cycle characteristics with pure refrigerants, the cycle analysis for Refrigerants 502, 13B1, 152a, 717 (NH3) and 290 (C3H8) was also examined. It became clear that the maximum coefficients of performance with various refrigerants were obtained at the reduced condensing temperature being 0.9 when the same temperature difference between condensing and evaporating temperature was chosen.
Theoretical analysis of on-chip linear quantum optical information processing networks
NASA Astrophysics Data System (ADS)
Hach, Edwin E.; Preble, Stefan F.; Steidle, Jeffrey A.
2015-05-01
We present a quantum optical analysis of waveguides directionally coupled to ring resonators, an architecture realizable using silicon nanophotonics. The innate scalability of the silicon platform allows for the possibility of "on-chip" quantum computation and information processing. In this paper, we briefly review a comprehensive method for analyzing the quantum mechanical output of such a network for an arbitrary input state of the quantized, traveling electromagnetic field in the continuous wave (cw) limit. Specifically, we briefly review a recent theoretical result identifying a particular device topology that yields, via Passive Quantum Optical Feedback (PQOF), dramatic and unexpected enhancements of the Hong-Ou-Mandel Effect, an effect central to the operation of many quantum information processing systems. Next, we extend the analysis to our proposal for a scalable, on-chip realization of the Nonlinear Sign (NS) shifter essential for implementation of the Knill-Laflamme-Milburn (KLM) protocol for Linear Optical Quantum Computing (LOQC). Finally, we discuss generalizations to arbitrary networks of directionally coupled ring resonators along with possible applications is the areas of quantum metrology and sensitive photon detection.
NASA Astrophysics Data System (ADS)
Hernández, Damián G.; Zanette, Damián H.; Samengo, Inés
2015-08-01
We develop the information-theoretical concepts required to study the statistical dependencies among three variables. Some of such dependencies are pure triple interactions, in the sense that they cannot be explained in terms of a combination of pairwise correlations. We derive bounds for triple dependencies, and characterize the shape of the joint probability distribution of three binary variables with high triple interaction. The analysis also allows us to quantify the amount of redundancy in the mutual information between pairs of variables, and to assess whether the information between two variables is or is not mediated by a third variable. These concepts are applied to the analysis of written texts. We find that the probability that a given word is found in a particular location within the text is not only modulated by the presence or absence of other nearby words, but also, on the presence or absence of nearby pairs of words. We identify the words enclosing the key semantic concepts of the text, the triplets of words with high pairwise and triple interactions, and the words that mediate the pairwise interactions between other words.
Zhu, Siwen; Li, Hongping; Zhu, Wenshuai; Jiang, Wei; Wang, Chao; Wu, Peiwen; Zhang, Qi; Li, Huaming
2016-07-01
Deep eutectic solvents (DESs), as ionic liquid analogues for green solvents, have gained increasing attentions in chemistry. In this work, three typical kinds of DESs (ChCl/Gly, ChCl/AcOH and ChCl/Urea) were successfully synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and Raman. Then comprehensive and systematical analyses were performed by the methods of density functional theory (DFT). Two methods (B3LYP/6-311++G(2d,p) and dispersion-corrected B3LYP-D3/6-311++G(2d,p)) were employed to investigate the structures, vibrational frequencies and assign their ownership of vibrational modes for the DESs, respectively. Nearly all the experimental characteristic peaks of IR and Raman were identified according to the calculated results. By linear fitting of the combined calculated vs experimental vibration frequencies, it can be found that both of the two methods are excellent to reproduce the experimental results. Besides, hydrogen bonds were proved to exist in DESs by IR spectrum, structure analysis and RDG analysis. This work was aimed at predicting and understanding the vibrational spectra of the three typical DESs based on DFT methods. Moreover, by comparing experimental and theoretical results, it provides us a deep understanding of the formation mechanisms of DESs. PMID:27450770
NASA Astrophysics Data System (ADS)
Berezovska, Ganna; Prada-Gracia, Diego; Mostarda, Stefano; Rao, Francesco
2012-11-01
Molecular simulations as well as single molecule experiments have been widely analyzed in terms of order parameters, the latter representing candidate probes for the relevant degrees of freedom. Notwithstanding this approach is very intuitive, mounting evidence showed that such descriptions are inaccurate, leading to ambiguous definitions of states and wrong kinetics. To overcome these limitations a framework making use of order parameter fluctuations in conjunction with complex network analysis is investigated. Derived from recent advances in the analysis of single molecule time traces, this approach takes into account the fluctuations around each time point to distinguish between states that have similar values of the order parameter but different dynamics. Snapshots with similar fluctuations are used as nodes of a transition network, the clusterization of which into states provides accurate Markov-state-models of the system under study. Application of the methodology to theoretical models with a noisy order parameter as well as the dynamics of a disordered peptide illustrates the possibility to build accurate descriptions of molecular processes on the sole basis of order parameter time series without using any supplementary information.
Gungor, M.R.; Maroudas, D.
1999-02-01
Failure of metallic thin films driven by electromigration is among the most challenging materials reliability problems in microelectronics toward ultra-large-scale integration. One of the most serious failure mechanisms in thin films with bamboo grain structure is the propagation of transgranular voids, which may lead to open-circuit failure. In this article, a comprehensive theoretical analysis is presented of the complex nonlinear dynamics of transgranular voids in metallic thin films as determined by capillarity-driven surface diffusion coupled with drift induced by electromigration. Our analysis is based on self-consistent dynamical simulations of void morphological evolution and it is aided by the conclusions of an approximate linear stability theory. Our simulations emphasize that the strong dependence of surface diffusivity on void surface orientation, the strength of the applied electric field, and the void size play important roles in the dynamics of the voids. The simulations predict void faceting, formation of wedge-shaped voids due to facet selection, propagation of slit-like features emanating from void surfaces, open-circuit failure due to slit propagation, as well as appearance and disappearance of soliton-like features on void surfaces prior to failure. These predictions are in very good agreement with recent experimental observations during accelerated electromigration testing of unpassivated metallic films. The simulation results are used to establish conditions for the formation of various void morphological features and discuss their serious implications for interconnect reliability. {copyright} {ital 1999 American Institute of Physics.}
Hand-held resonance sensor for tissue stiffness measurements—a theoretical and experimental analysis
NASA Astrophysics Data System (ADS)
Jalkanen, Ville
2010-05-01
A piezoelectric transducer in a feedback circuit operating in a resonance state is the basis of a resonance sensor. Upon contact with a soft object a change in the resonance frequency reflects the acoustic impedance. Together with force measurement it is possible to obtain the elastic stiffness of the object. The aim of this study was to evaluate the concept of a hand-held resonance sensor for tissue stiffness measurement. A time derivative analysis of the force and the frequency change showed that a stiffness-sensitive parameter was independent of the impression speed. Soft tissue phantoms of gelatin were used in an experimental validation of the theory. A force indentation method was used as a reference method for assessing the gelatin's elastic stiffness. Results from the hand-held measurements showed that the stiffness parameter accurately measured the elastic stiffness of the gelatin (R2 = 0.94, p < 0.05). The stiffness parameter was weakly (on average R2 = 0.15) and non-significantly (p > 0.05, 14 out of 17) dependent on an impression speed parameter. On average, a small amount of the total variance was explained by the impression speed. In conclusion, soft tissue stiffness can be objectively measured with free-hand measurement with a resonance sensor. This study contributes a theoretical analysis and an experimental demonstration of the concept of a hand-held resonance sensor for stiffness measurements.
Armendáriz-Vidales, Georgina; Frontana, Carlos
2014-09-01
An electrochemical and theoretical analysis of a series of shikonin derivatives in aprotic media is presented. Results showed that the first electrochemical reduction signal is a reversible monoelectronic transfer, generating a stable semiquinone intermediate; the corresponding E(I)⁰ values were correlated with calculated values of electroaccepting power (ω(+)) and adiabatic electron affinities (A(Ad)), obtained with BH and HLYP/6-311++G(2d,2p) and considering the solvent effect, revealing the influence of intramolecular hydrogen bonding and the substituting group at position C-2 in the experimental reduction potential. For the second reduction step, esterified compounds isobutyryl and isovalerylshikonin presented a coupled chemical reaction following dianion formation. Analysis of the variation of the dimensionless cathodic peak potential values (ξ(p)) as a function of the scan rate (v) functions and complementary experiments in benzonitrile suggested that this process follows a dissociative electron transfer, in which the rate of heterogeneous electron transfer is slow (~0.2 cm s(-1)), and the rate constant of the chemical process is at least 10(5) larger. PMID:25007856
Moral distress: a comparative analysis of theoretical understandings and inter-related concepts.
Lützén, Kim; Kvist, Beatrice Ewalds
2012-03-01
Research on ethical dilemmas in health care has become increasingly salient during the last two decades resulting in confusion about the concept of moral distress. The aim of the present paper is to provide an overview and a comparative analysis of the theoretical understandings of moral distress and related concepts. The focus is on five concepts: moral distress, moral stress, stress of conscience, moral sensitivity and ethical climate. It is suggested that moral distress connects mainly to a psychological perspective; stress of conscience more to a theological-philosophical standpoint; and moral stress mostly to a physiological perspective. Further analysis indicates that these thoughts can be linked to the concepts of moral sensitivity and ethical climate through a relationship to moral agency. Moral agency comprises a moral awareness of moral problems and moral responsibility for others. It is suggested that moral distress may serve as a positive catalyst in exercising moral agency. An interdisciplinary approach in research and practice broadens our understanding of moral distress and its impact on health care personnel and patient care. PMID:22454155
Wettability of graphitic-carbon and silicon surfaces: MD modeling and theoretical analysis
Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.
2015-07-28
The wettability of graphitic carbon and silicon surfaces was numerically and theoretically investigated. A multi-response method has been developed for the analysis of conventional molecular dynamics (MD) simulations of droplets wettability. The contact angle and indicators of the quality of the computations are tracked as a function of the data sets analyzed over time. This method of analysis allows accurate calculations of the contact angle obtained from the MD simulations. Analytical models were also developed for the calculation of the work of adhesion using the mean-field theory, accounting for the interfacial entropy changes. A calibration method is proposed to provide better predictions of the respective contact angles under different solid-liquid interaction potentials. Estimations of the binding energy between a water monomer and graphite match those previously reported. In addition, a breakdown in the relationship between the binding energy and the contact angle was observed. The macroscopic contact angles obtained from the MD simulations were found to match those predicted by the mean-field model for graphite under different wettability conditions, as well as the contact angles of Si(100) and Si(111) surfaces. Finally, an assessment of the effect of the Lennard-Jones cutoff radius was conducted to provide guidelines for future comparisons between numerical simulations and analytical models of wettability.
Theoretical analysis of saturation and limit cycles in short pulse FEL oscillators
Piovella, N.; Chaix, P.; Jaroszynski, D.
1995-12-31
We derive a model for the non linear evolution of a short pulse oscillator from low signal up to saturation in the small gain regime. This system is controlled by only two independent parameters: cavity detuning and losses. Using a closure relation, this model reduces to a closed set of 5 non linear partial differential equations for the EM field and moments of the electron distribution. An analysis of the linearised system allows to define and calculate the eigenmodes characterising the small signal regime. An arbitrary solution of the complete nonlinear system can then be expanded in terms of these eigenmodes. This allows interpreting various observed nonlinear behaviours, including steady state saturation, limit cycles, and transition to chaos. The single mode approximation reduces to a Landau-Ginzburg equation. It allows to obtain gain, nonlinear frequency shift, and efficiency as functions of cavity detuning and cavity losses. A generalisation to two modes allows to obtain a simple description of the limit cycle behaviour, as a competition between these two modes. An analysis of the transitions to more complex dynamics is also given. Finally, the analytical results are compared to the experimental data from the FELIX experiment.
NASA Astrophysics Data System (ADS)
Peña-Sancho, Carolina; Ghezzehei, Teamrat A.; Latorre, Borja; Moret-Fernández, David
2015-04-01
The determination of the water retention curve (WRC) parameters and the hydraulic conductivity (K) is of paramount importance in many scientific fields such as hydrology or environmental science. Their direct characterization, however, is typically cumbersome and time consuming. This work analyze the viability to estimate the α and n Van Genuchten (VG) WRC parameters and K from following processes: a capillary wetting process at saturation, an evaporation process and a capillary wetting at saturation followed by an evaporation process. The theoretical analysis was carried out on a 5 cm high and 5 cm diameter cylinder filled with loam soil using numerically generated data with the HYDRUS 2D code. The error maps for the above mentioned processes and the n-K, α-n and K-α planes were generated from the RMSE calculated between the original and the simulated cumulative curves. The deviation (%) between the optimal and original hydraulic parameters was also calculated. Results showed that the capillary plus evaporation method applied on the n-K and α-n planes was the unique process that allowed a unique and well defined minimum. For this last case, the deviation for the α and n parameter were 6'67 and 0'88%, respectively. Taking into account that K can be easy measured from the same soil cylinder by means of Darcy's law, we conclude the capillary + evaporation process can be a simple and effective alternative to estimate the WRC parameters. To this end, the hysteresis phenomena due to the wetting-evaporation process should be taking into account.
Design and analysis of simple choice surveys for natural resource management
Fieberg, John; Cornicelli, Louis; Fulton, David C.; Grund, Marrett D.
2010-01-01
We used a simple yet powerful method for judging public support for management actions from randomized surveys. We asked respondents to rank choices (representing management regulations under consideration) according to their preference, and we then used discrete choice models to estimate probability of choosing among options (conditional on the set of options presented to respondents). Because choices may share similar unmodeled characteristics, the multinomial logit model, commonly applied to discrete choice data, may not be appropriate. We introduced the nested logit model, which offers a simple approach for incorporating correlation among choices. This forced choice survey approach provides a useful method of gathering public input; it is relatively easy to apply in practice, and the data are likely to be more informative than asking constituents to rate attractiveness of each option separately.
Connecting the dots : analysis, development and applications of the SimpleX algorithm
NASA Astrophysics Data System (ADS)
Kruip, Chael
2011-11-01
The SimpleX radiative transfer method is based on the interpretation of photons as particles interacting on a natural scale: the local mean free path. In our method, light is transported along the lines of an unstructured Delaunay mesh that encodes this natural distance and represents the physical medium. The SimpleX method is fast, highly adaptive and its computational cost does not scale with the number of sources. It is therefore well-suited for cosmological applications where it is essential to cover many orders of magnitude in resolution and where millions of sources can exist within a single simulation. We describe the code, its recent developments and apply it to several relevant astrophysical problems. In particular, we perform radiative transfer calculations of cosmological reionization and of the wind-wind interaction region of the Eta Carinae binary system.
Language in the brain at rest: new insights from resting state data and graph theoretical analysis.
Muller, Angela M; Meyer, Martin
2014-01-01
In humans, the most obvious functional lateralization is the specialization of the left hemisphere for language. Therefore, the involvement of the right hemisphere in language is one of the most remarkable findings during the last two decades of fMRI research. However, the importance of this finding continues to be underestimated. We examined the interaction between the two hemispheres and also the role of the right hemisphere in language. From two seeds representing Broca's area, we conducted a seed correlation analysis (SCA) of resting state fMRI data and could identify a resting state network (RSN) overlapping to significant extent with a language network that was generated by an automated meta-analysis tool. To elucidate the relationship between the clusters of this RSN, we then performed graph theoretical analyses (GTA) using the same resting state dataset. We show that the right hemisphere is clearly involved in language. A modularity analysis revealed that the interaction between the two hemispheres is mediated by three partitions: A bilateral frontal partition consists of nodes representing the classical left sided language regions as well as two right-sided homologs. The second bilateral partition consists of nodes from the right frontal, the left inferior parietal cortex as well as of two nodes within the posterior cerebellum. The third partition is also bilateral and comprises five regions from the posterior midline parts of the brain to the temporal and frontal cortex, two of the nodes are prominent default mode nodes. The involvement of this last partition in a language relevant function is a novel finding. PMID:24808843
Language in the brain at rest: new insights from resting state data and graph theoretical analysis
Muller, Angela M.; Meyer, Martin
2014-01-01
In humans, the most obvious functional lateralization is the specialization of the left hemisphere for language. Therefore, the involvement of the right hemisphere in language is one of the most remarkable findings during the last two decades of fMRI research. However, the importance of this finding continues to be underestimated. We examined the interaction between the two hemispheres and also the role of the right hemisphere in language. From two seeds representing Broca's area, we conducted a seed correlation analysis (SCA) of resting state fMRI data and could identify a resting state network (RSN) overlapping to significant extent with a language network that was generated by an automated meta-analysis tool. To elucidate the relationship between the clusters of this RSN, we then performed graph theoretical analyses (GTA) using the same resting state dataset. We show that the right hemisphere is clearly involved in language. A modularity analysis revealed that the interaction between the two hemispheres is mediated by three partitions: A bilateral frontal partition consists of nodes representing the classical left sided language regions as well as two right-sided homologs. The second bilateral partition consists of nodes from the right frontal, the left inferior parietal cortex as well as of two nodes within the posterior cerebellum. The third partition is also bilateral and comprises five regions from the posterior midline parts of the brain to the temporal and frontal cortex, two of the nodes are prominent default mode nodes. The involvement of this last partition in a language relevant function is a novel finding. PMID:24808843
NASA Astrophysics Data System (ADS)
Volkov, Alexey N.; Salaway, Richard N.; Zhigilei, Leonid V.
2013-09-01
The propensity of carbon nanotubes (CNTs) to self-organize into continuous networks of bundles has direct implications for thermal transport properties of CNT network materials and defines the importance of clear understanding of the mechanisms and scaling laws governing the heat transfer within the primary building blocks of the network structures—close-packed bundles of CNTs. A comprehensive study of the thermal conductivity of CNT bundles is performed with a combination of non-equilibrium molecular dynamics (MD) simulations of heat transfer between adjacent CNTs and the intrinsic conductivity of CNTs in a bundle with a theoretical analysis that reveals the connections between the structure and thermal transport properties of CNT bundles. The results of MD simulations of heat transfer in CNT bundles consisting of up to 7 CNTs suggest that, contrary to the widespread notion of strongly reduced conductivity of CNTs in bundles, van der Waals interactions between defect-free well-aligned CNTs in a bundle have negligible effect on the intrinsic conductivity of the CNTs. The simulations of inter-tube heat conduction performed for partially overlapping parallel CNTs indicate that the conductance through the overlap region is proportional to the length of the overlap for CNTs and CNT-CNT overlaps longer than several tens of nm. Based on the predictions of the MD simulations, a mesoscopic-level model is developed and applied for theoretical analysis and numerical modeling of heat transfer in bundles consisting of CNTs with infinitely large and finite intrinsic thermal conductivities. The general scaling laws predicting the quadratic dependence of the bundle conductivity on the length of individual CNTs in the case when the thermal transport is controlled by the inter-tube conductance and the independence of the CNT length in another limiting case when the intrinsic conductivity of CNTs plays the dominant role are derived. An application of the scaling laws to bundles of
An effectiveness analysis of healthcare systems using a systems theoretic approach
Chuang, Sheuwen; Inder, Kerry
2009-01-01
Background The use of accreditation and quality measurement and reporting to improve healthcare quality and patient safety has been widespread across many countries. A review of the literature reveals no association between the accreditation system and the quality measurement and reporting systems, even when hospital compliance with these systems is satisfactory. Improvement of health care outcomes needs to be based on an appreciation of the whole system that contributes to those outcomes. The research literature currently lacks an appropriate analysis and is fragmented among activities. This paper aims to propose an integrated research model of these two systems and to demonstrate the usefulness of the resulting model for strategic research planning. Methods/design To achieve these aims, a systematic integration of the healthcare accreditation and quality measurement/reporting systems is structured hierarchically. A holistic systems relationship model of the administration segment is developed to act as an investigation framework. A literature-based empirical study is used to validate the proposed relationships derived from the model. Australian experiences are used as evidence for the system effectiveness analysis and design base for an adaptive-control study proposal to show the usefulness of the system model for guiding strategic research. Results Three basic relationships were revealed and validated from the research literature. The systemic weaknesses of the accreditation system and quality measurement/reporting system from a system flow perspective were examined. The approach provides a system thinking structure to assist the design of quality improvement strategies. The proposed model discovers a fourth implicit relationship, a feedback between quality performance reporting components and choice of accreditation components that is likely to play an important role in health care outcomes. An example involving accreditation surveyors is developed that
Dasi, Lakshmi P.; Pekkan, Kerem; de Zelicourt, Diane; Sundareswaran, Kartik S.; Krishnankutty, Resmi; Delnido, Pedro J.; Yoganathan, Ajit P.
2010-01-01
Background We present a fundamental theoretical framework for analysis of energy dissipation in any component of the circulatory system and formulate the full energy budget for both venous and arterial circulations. New indices allowing disease-specific subject-to-subject comparisons and disease-to-disease hemodynamic evaluation (quantifying the hemodynamic severity of one vascular disease type to the other) are presented based on this formalism. Methods and Results Dimensional analysis of energy dissipation rate with respect to the human circulation shows that the rate of energy dissipation is inversely proportional to the square of the patient body surface area and directly proportional to the cube of cardiac output. This result verified the established formulae for energy loss in aortic stenosis that was solely derived through empirical clinical experience. Three new indices are introduced to evaluate more complex disease states: (1) circulation energy dissipation index (CEDI), (2) aortic valve energy dissipation index (AV-EDI), and (3) total cavopulmonary connection energy dissipation index (TCPCEDI). CEDI is based on the full energy budget of the circulation and is the proper measure of the work performed by the ventricle relative to the net energy spent in overcoming frictional forces. It is shown to be 4.01 ± 0.16 for healthy individuals and above 7.0 for patients with severe aortic stenosis. Application of CEDI index on single-ventricle venous physiology reveals that the surgically created Fontan circulation, which is indeed palliative, progressively degrades in hemodynamic efficiency with growth (p <0.001), with the net dissipation in a typical Fontan patient (Body surface area = 1.0 m2) being equivalent to that of an average case of severe aortic stenosis. AV-EDI is shown to be the proper index to gauge the hemodynamic severity of stenosed aortic valves as it accurately reflects energy loss. It is about 0.28 ± 0.12 for healthy human valves. Moderate
NASA Astrophysics Data System (ADS)
Mareschal, M.; Jouanne, V.; Menvielle, M.; Chouteau, M.; Grandis, H.; Tarits, P.
1992-12-01
A simple impedance tensor analysis of four magnetotelluric soundings recorded over the ECORS section of the Rhine Graben shows that for periods shorter than about 30 s, induction dominates over channelling. For longer periods, 2-D induction galvanically distorted by surface heterogeneities and/or current chanelled in the Graben can explain the observations; the role of chanelling becomes dominant at periods of the order of a few hundred seconds. In the area considered, induction appears to be controlled by inclusions of saline water in a porous limestone layer (Grande Oolithe) and not by the limits of the Graben with its crystalline shoulder (Vosges). The simple analysis is supported by tipper analyses and by the results of schematic 2-D modelling.
The energy release rate of the fiber/polymer matrix interface: Measurement and theoretical analysis
Hampe, A.; Marotzke, C.
1995-12-31
A new method for the experimental determination of the fracture toughness in the fiber matrix interface by means of the single fiber pull out test is presented. To achieve this aim, two problems had to be overcome: the measurement of the compliance of a partial debonded fiber, which necessitates a stable crack propagation, and the determination of the corresponding crack length. Stable crack propagation along the interface of a single fiber is achieved using an advanced test equipment exhibiting an extremely high stiffness. This is obtained by using a piezo translator and a piezo force cell in combination with a very short free fiber length. The experimental data and a theoretical analysis of the pull out process under these conditions reveal, that the commonly used compliant pull out equipment is hiding important details of the force displacement trace and thus leading to a wrong interpretation and wrong results, The most important result is, that in the case of a brittle interfacial fracture the maximal force cannot be used for the determination of an interfacial strength as it is common practice till now.
Experimental and theoretical analysis of vortex breakdown in the wake of the 25∘ Ahmed body
NASA Astrophysics Data System (ADS)
Jermann, Cyril; Meliga, Philippe; Pujals, Gregory; Gallaire, Francois; Serre, Eric
2014-11-01
We study experimentally and theoretically the wake of the 25circ; Ahmed body, considered a suitable test-case to reproduce the two counter-rotating longitudinal vortices widely encountered in automotive aerodynamics. The three-dimensional experimental mean flow is reconstructed at high Reynolds number (Re = 2 . 8 ×106) from a series of cross-flow time-averaged planes acquired with a moving automated Stereo-PIV system. We observe a sharp decay of the axial velocity and vorticity in the near-wake, 0 . 5 times the projected length of the slanted surface downstream the square back, where the streamwise vortices is subjected to a strong adverse pressure gradient and the turbulent kinetic energy exhibits a peak in the vortex core. A stability analysis of the experimental velocity shows that the flow undergoes vortex breakdown roughly at the same position, through a transition from supercritical (x < 0 . 5) to subcritical (x > 0 . 5) conditions and the accumulation of upstream propagating axisymmetric waves.
NASA Astrophysics Data System (ADS)
Gui-Li, Zheng; Hui, Zhang; Wen-Jiang, Ye; Zhi-Dong, Zhang; Hong-Wei, Song; Li, Xuan
2016-03-01
Based on the experimental phenomena of flexoelectric response at defect sites in nematic inversion walls conducted by Kumar et al., we gave the theoretical analysis using the Frank elastic theory. When a direct-current electric field normal to the plane of the substrate is applied to the parallel aligned nematic liquid crystal cell with weak anchoring, the rotation of ±1 defects in the narrow inversion walls can be exhibited. The free energy of liquid crystal molecules around the +1 and -1 defect sites in the nematic inversion walls under the electric field was formulated and the electric-field-driven structural changes at the defect site characterized by polar and azimuthal angles of the local director were simulated. The results reveal that the deviation of azimuthal angle induced by flexoelectric effect are consistent with the switching of extinction brushes at the +1 and -1 defects obtained in the experiment conducted by Kumar et al. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374087, 11274088, and 11304074), the Natural Science Foundation of Hebei Province, China (Grant Nos. A2014202123 and A2016202282), the Research Project of Hebei Education Department, China (Grant Nos. QN2014130 and QN2015260), and the Key Subject Construction Project of Hebei Province University, China.
Parametric sensitivity analysis for stochastic molecular systems using information theoretic metrics
Tsourtis, Anastasios; Pantazis, Yannis Katsoulakis, Markos A.; Harmandaris, Vagelis
2015-07-07
In this paper, we present a parametric sensitivity analysis (SA) methodology for continuous time and continuous space Markov processes represented by stochastic differential equations. Particularly, we focus on stochastic molecular dynamics as described by the Langevin equation. The utilized SA method is based on the computation of the information-theoretic (and thermodynamic) quantity of relative entropy rate (RER) and the associated Fisher information matrix (FIM) between path distributions, and it is an extension of the work proposed by Y. Pantazis and M. A. Katsoulakis [J. Chem. Phys. 138, 054115 (2013)]. A major advantage of the pathwise SA method is that both RER and pathwise FIM depend only on averages of the force field; therefore, they are tractable and computable as ergodic averages from a single run of the molecular dynamics simulation both in equilibrium and in non-equilibrium steady state regimes. We validate the performance of the extended SA method to two different molecular stochastic systems, a standard Lennard-Jones fluid and an all-atom methane liquid, and compare the obtained parameter sensitivities with parameter sensitivities on three popular and well-studied observable functions, namely, the radial distribution function, the mean squared displacement, and the pressure. Results show that the RER-based sensitivities are highly correlated with the observable-based sensitivities.
Intrinsic functional brain architecture derived from graph theoretical analysis in the human fetus.
Thomason, Moriah E; Brown, Jesse A; Dassanayake, Maya T; Shastri, Rupal; Marusak, Hilary A; Hernandez-Andrade, Edgar; Yeo, Lami; Mody, Swati; Berman, Susan; Hassan, Sonia S; Romero, Roberto
2014-01-01
The human brain undergoes dramatic maturational changes during late stages of fetal and early postnatal life. The importance of this period to the establishment of healthy neural connectivity is apparent in the high incidence of neural injury in preterm infants, in whom untimely exposure to ex-uterine factors interrupts neural connectivity. Though the relevance of this period to human neuroscience is apparent, little is known about functional neural networks in human fetal life. Here, we apply graph theoretical analysis to examine human fetal brain connectivity. Utilizing resting state functional magnetic resonance imaging (fMRI) data from 33 healthy human fetuses, 19 to 39 weeks gestational age (GA), our analyses reveal that the human fetal brain has modular organization and modules overlap functional systems observed postnatally. Age-related differences between younger (GA <31 weeks) and older (GA≥31 weeks) fetuses demonstrate that brain modularity decreases, and connectivity of the posterior cingulate to other brain networks becomes more negative, with advancing GA. By mimicking functional principles observed postnatally, these results support early emerging capacity for information processing in the human fetal brain. Current technical limitations, as well as the potential for fetal fMRI to one day produce major discoveries about fetal origins or antecedents of neural injury or disease are discussed. PMID:24788455
A novel self-powered MR damper: theoretical and experimental analysis
NASA Astrophysics Data System (ADS)
Xinchun, Guan; Yonghu, Huang; Yi, Ru; Hui, Li; Jinping, Ou
2015-10-01
This paper presents a novel magnetorheological (MR) damper with a self-powered capability, which is proposed to have energy harvesting and MR damping technologies integrated into a single device. Vibration energy harvesting mechanisms were adopted, based on ball-screw mechanisms and a rotary permanent magnet dc generator, to convert the external vibration energy into electrical energy to power the MR damping unit. The configuration and operating principles of the proposed self-powered MR damper were presented. Considering the core loss effect on the magnetic field, a theoretical analysis of the proposed MR damper was carried out and a mechanical model was developed. Finally, a prototype with a capacity of 10 kN was fabricated and experimentally investigated in both the direct-supply mode and the supply-with-rectifier mode. The results indicated that the proposed configuration is feasible and that both modes can realize good self-adaptability of the MR damping force. However, the direct-supply mode has a sag effect in the force-displacement curve and provides a lower energy-dissipating capacity than the direct-supply mode does under the same conditions.
Theoretical Analysis of X-ray Compound Refractive Lens Optical Properties
Kohn, V.; Snigireva, I.; Snigirev, A.
2004-05-12
We present a theoretical analysis of optical properties of parabolic compound refractive lenses (CRL). The parabolic CRL with a large number of elements is considered as a parabolic medium along the x-ray path. The problem of x-ray coherent wave propagation inside such a medium is solved exactly. The analytical formula is obtained for the parabolic CRL imaging propagator as a parabolic wave with complex parameters due to absorption of x rays inside the lens. The fast and universal computer program is developed for simulating the CRL generated images. An imaging example of a test object as a silicon plate of 3 {mu}m thickness with a round hole of 3 {mu}m diameter is presented and discussed in details. The main optical parameters of parabolic CRL such as an effective aperture, a diffraction limited resolution and a focal distance are calculated analytically and discussed. It is shown that parabolic CRL has no spherical aberration while long single plano-concave and bi-concave lenses have.
Theoretical analysis of transcranial Hall-effect stimulation based on passive cable model
NASA Astrophysics Data System (ADS)
Yuan, Yi; Li, Xiao-Li
2015-12-01
Transcranial Hall-effect stimulation (THS) is a new stimulation method in which an ultrasonic wave in a static magnetic field generates an electric field in an area of interest such as in the brain to modulate neuronal activities. However, the biophysical basis of simulating the neurons remains unknown. To address this problem, we perform a theoretical analysis based on a passive cable model to investigate the THS mechanism of neurons. Nerve tissues are conductive; an ultrasonic wave can move ions embedded in the tissue in a static magnetic field to generate an electric field (due to Lorentz force). In this study, a simulation model for an ultrasonically induced electric field in a static magnetic field is derived. Then, based on the passive cable model, the analytical solution for the voltage distribution in a nerve tissue is determined. The simulation results showthat THS can generate a voltage to stimulate neurons. Because the THS method possesses a higher spatial resolution and a deeper penetration depth, it shows promise as a tool for treating or rehabilitating neuropsychiatric disorders. Project supported by the National Natural Science Foundation of China (Grant Nos. 61273063 and 61503321), the China Postdoctoral Science Foundation (Grant No. 2013M540215), the Natural Science Foundation of Hebei Province, China (Grant No. F2014203161), and the Youth Research Program of Yanshan University, China (Grant No. 02000134).
NASA Astrophysics Data System (ADS)
Liu, Y.; Yuan, H.; Vo-Dinh, T.
2013-03-01
Raman spectra measurements and density functional theory (DFT) calculations were performed to investigate three psoralens: 5-amino-8-methoxypsoralen (5-A-8-MOP), 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) with the aim of differentiating these similar bioactive molecules. The Raman spectra were recorded in the region 300-3500 cm-1. All three psoralens were found to have similar Raman spectrum in the region 1500-1650 cm-1. 5-A-8-MOP can be easily differentiated from 5-MOP or 8-MOP based on the Raman spectrum. The Raman spectrum differences at 651 and 795 cm-1 can be used to identify 5-MOP from 8-MOP. The theoretically computed vibrational frequencies and relative peak intensities were compared with experimental data. DFT calculations using the B3LYP method and 6-311++G(d,p) basis set were found to yield results that are very comparable to experimental Raman spectra. Detailed vibrational assignments were performed with DFT calculations and the potential energy distribution (PED) obtained from the Vibrational Energy Distribution Analysis (VEDA) program.
Game Theoretical Analysis on Cooperation Stability and Incentive Effectiveness in Community Networks
Liu, Yi; Qian, Depei; Zhang, Han; Cai, Jihong
2015-01-01
Community networks, the distinguishing feature of which is membership admittance, appear on P2P networks, social networks, and conventional Web networks. Joining the network costs money, time or network bandwidth, but the individuals get access to special resources owned by the community in return. The prosperity and stability of the community are determined by both the policy of admittance and the attraction of the privileges gained by joining. However, some misbehaving users can get the dedicated resources with some illicit and low-cost approaches, which introduce instability into the community, a phenomenon that will destroy the membership policy. In this paper, we analyze on the stability using game theory on such a phenomenon. We propose a game-theoretical model of stability analysis in community networks and provide conditions for a stable community. We then extend the model to analyze the effectiveness of different incentive policies, which could be used when the community cannot maintain its members in certain situations. Then we verify those models through a simulation. Finally, we discuss several ways to promote community network’s stability by adjusting the network’s properties and give some proposal on the designs of these types of networks from the points of game theory and stability. PMID:26551649
Smith, Robert; Fuss, Franz Konstantin
2013-01-01
This paper is a theoretical analysis of mirror tilt in a Michelson interferometer and its effect on the radiant flux over the active area of a rectangular photodetector or image sensor pixel. It is relevant to sensor applications using homodyne interferometry where these opto-electronic devices are employed for partial fringe counting. Formulas are derived for radiant flux across the detector for variable location within the fringe pattern and with varying wave front angle. The results indicate that the flux is a damped sine function of the wave front angle, with a decay constant of the ratio of wavelength to detector width. The modulation amplitude of the dynamic fringe pattern reduces to zero at wave front angles that are an integer multiple of this ratio and the results show that the polarity of the radiant flux changes exclusively at these multiples. Varying tilt angle causes radiant flux oscillations under an envelope curve, the frequency of which is dependent on the location of the detector with the fringe pattern. It is also shown that a fringe count of zero can be obtained for specific photodetector locations and wave front angles where the combined effect of fringe contraction and fringe tilt can have equal and opposite effects. Fringe tilt as a result of a wave front angle of 0.05° can introduce a phase measurement difference of 16° between a photodetector/pixel located 20 mm and one located 100 mm from the optical origin. PMID:24018954
Detection of allosteric signal transmission by information-theoretic analysis of protein dynamics.
Pandini, Alessandro; Fornili, Arianna; Fraternali, Franca; Kleinjung, Jens
2012-02-01
Allostery offers a highly specific way to modulate protein function. Therefore, understanding this mechanism is of increasing interest for protein science and drug discovery. However, allosteric signal transmission is difficult to detect experimentally and to model because it is often mediated by local structural changes propagating along multiple pathways. To address this, we developed a method to identify communication pathways by an information-theoretical analysis of molecular dynamics simulations. Signal propagation was described as information exchange through a network of correlated local motions, modeled as transitions between canonical states of protein fragments. The method was used to describe allostery in two-component regulatory systems. In particular, the transmission from the allosteric site to the signaling surface of the receiver domain NtrC was shown to be mediated by a layer of hub residues. The location of hubs preferentially connected to the allosteric site was found in close agreement with key residues experimentally identified as involved in the signal transmission. The comparison with the networks of the homologues CheY and FixJ highlighted similarities in their dynamics. In particular, we showed that a preorganized network of fragment connections between the allosteric and functional sites exists already in the inactive state of all three proteins. PMID:22071506
NASA Astrophysics Data System (ADS)
Beragoui, Manel; Aguir, Chadlia; Khalfaoui, Mohamed; Enciso, Eduardo; Torralvo, Maria José; Duclaux, Laurent; Reinert, Laurence; Vayer, Marylène; Ben Lamine, Abdelmottaleb
2015-03-01
The present work involves the study of bovine serum albumin adsorption onto five functionalized polystyrene lattices. The adsorption measurements have been carried out using a quartz crystal microbalance. Poly(styrene-co-itaconic acid) was found to be an effective adsorbent for bovine serum albumin molecule adsorption. The experimental isotherm data were analyzed using theoretical models based on a statistical physics approach, namely monolayer, double layer with two successive energy levels, finite multilayer, and modified Brunauer-Emmet-Teller. The equilibrium data were then analyzed using five different non-linear error analysis methods and it was found that the finite multilayer model best describes the protein adsorption data. Surface characteristics, i.e., surface charge density and number density of surface carboxyl groups, were used to investigate their effect on the adsorption capacity. The combination of the results obtained from the number of adsorbed layers, the number of adsorbed molecules per site, and the thickness of the adsorbed bovine serum albumin layer allows us to predict that the adsorption of this protein molecule can also be distinguished by monolayer or multilayer adsorption with end-on, side-on, and overlap conformations. The magnitudes of the calculated adsorption energy indicate that bovine serum albumin molecules are physisorbed onto the adsorbent lattices.
Song, Kaida; Wang, Rui; Liu, Yi; Qian, Depei; Zhang, Han; Cai, Jihong
2015-01-01
Community networks, the distinguishing feature of which is membership admittance, appear on P2P networks, social networks, and conventional Web networks. Joining the network costs money, time or network bandwidth, but the individuals get access to special resources owned by the community in return. The prosperity and stability of the community are determined by both the policy of admittance and the attraction of the privileges gained by joining. However, some misbehaving users can get the dedicated resources with some illicit and low-cost approaches, which introduce instability into the community, a phenomenon that will destroy the membership policy. In this paper, we analyze on the stability using game theory on such a phenomenon. We propose a game-theoretical model of stability analysis in community networks and provide conditions for a stable community. We then extend the model to analyze the effectiveness of different incentive policies, which could be used when the community cannot maintain its members in certain situations. Then we verify those models through a simulation. Finally, we discuss several ways to promote community network's stability by adjusting the network's properties and give some proposal on the designs of these types of networks from the points of game theory and stability. PMID:26551649
Theoretical Analysis of Oxygen Vacancy Formation in Zr-Doped BaTiO3
NASA Astrophysics Data System (ADS)
Umeda, Yuji; Takano, Kosuke; Kojima, Takashi; Kuwabara, Akihide; Moriwake, Hiroki
2012-09-01
One of the most serious problems for the development of multilayer ceramic capacitors (MLCCs) is that their electrical resistance decreases under long-term DC voltage. Oxygen vacancy migration in BaTiO3 is thought to be one cause of this deterioration. In this study, to understand this mechanism, quantitative analysis of the oxygen vacancy formation energy [Ef(VO)] in Zr-doped and undoped BaTiO3 was performed. The Ef(VO) of Zr-doped BaTiO3 was higher than that of undoped BaTiO3 because the valence of Ti in undoped BaTiO3 easily changed from +4 to +3 owing to oxygen vacancy formation, compared with that in Zr-doped BaTiO3. We also prepared undoped (BaTiO3) and Zr-doped (BaZr0.05Ti0.95O3) ceramic samples sintered under reducing atmosphere (T = 1573 K pO2 = 10-13 MPa). BaZr0.05Ti0.95O3 remained an insulator, but BaTiO3 showed semiconducting behavior. This experimental result corresponds well to theoretical results of first-principles calculations.
NASA Astrophysics Data System (ADS)
Chandler, David W.; Miller, James A.
1984-07-01
We have used the master equation formalism to analyze the photoactivated unimolecular dissociation of a large polyatomic molecule, t-butyl hydroperoxide (t-BuOOH). Our results are compared to the experimental results of Chandler, Farneth, and Zare and of Chuang et al. We find that the curvature in their Stern-Volmer plots cannot be explained by a collisional energy transfer mechanism. At high pressure, the theoretical Stern-Volmer plots are linear, independent of the collisional energy transfer properties. This linearity is related to the existence of a limiting high pressure ``reactive distribution.'' We identify three different pressure regimes that exist in photoactivated unimolecular reaction experiments, and we relate these regimes to the properties of the reactive distribution. In particular, we find that, when a Stern-Volmer analysis is used, curvature at very low pressure can result in systematic errors in determining the unimolecular rate constants. In addition, we have successfully analyzed the real time experiments of Rizzo and Crim using the same molecular model and parameters necessary to predict the experiments of Chandler et al.
Chandler, D.W.; Miller, J.A.
1984-07-01
We have used the master equation formalism to analyze the photoactivated unimolecular dissociation of a large polyatomic molecule, t-butyl hydroperoxide (t-BuOOH). Our results are compared to the experimental results of Chandler, Farneth, and Zare and of Chuang et al. We find that the curvature in their Stern-Volmer plots cannot be explained by a collisional energy transfer mechanism. At high pressure, the theoretical Stern--Volmer plots are linear, independent of the collisional energy transfer properties. This linearity is related to the existence of a limiting high pressure ''reactive distribution.'' We identify three different pressure regimes that exist in photoactivated unimolecular reaction experiments, and we relate these regimes to the properties of the reactive distribution. In particular, we find that, when a Stern-Volmer analysis is used, curvature at very low pressure can result in systematic errors in determining the unimolecular rate constants. In addition, we have successfully analyzed the real time experiments of Rizzo and Crim using the same molecular model and parameters necessary to predict the experiments of Chandler et al.
Aouafi, A.; Bouvier, S.; Gasperini, M.; Lemoine, X.; Bouaziz, O.
2007-04-07
Reverse simple shear tests are used to analyse the Bauschinger effect and the evolution of the kinematic hardening for a wide range of equivalent von Mises strain [0.025 - 0.3]. This work is carried out on two high strength low-alloyed steels. In order to investigate the effect of the precipitates on the macroscopic behaviour, a ferritic mild steel is used as a reference. Different phenomenological descriptions of the back-stress tensor are examined in order to analyse their ability to describe the experimental behaviour.
NASA Astrophysics Data System (ADS)
Aouafi, A.; Bouvier, S.; Gaspérini, M.; Lemoine, X.; Bouaziz, O.
2007-04-01
Reverse simple shear tests are used to analyse the Bauschinger effect and the evolution of the kinematic hardening for a wide range of equivalent von Mises strain [0.025 - 0.3]. This work is carried out on two high strength low-alloyed steels. In order to investigate the effect of the precipitates on the macroscopic behaviour, a ferritic mild steel is used as a reference. Different phenomenological descriptions of the back-stress tensor are examined in order to analyse their ability to describe the experimental behaviour.
Survey and analysis of simple sequence repeats (SSRs) present in the genomes of plant viroids.
Qin, Lü; Zhang, Zhixiang; Zhao, Xiangyan; Wu, Xiaolong; Chen, Yubao; Tan, Zhongyang; Li, Shifang
2014-01-01
Extensive simple sequence repeat (SSR) surveys have been performed for eukaryotic prokaryotic and viral genomes, but information regarding SSRs in viroids is limited. We undertook a survey to examine the presence of SSRs in viroid genomes. Our results show that the distribution of SSRs in viroids may influence secondary structure, and that SSRs could play a role in generating genetic diversity. We also discuss the potential evolutionary role of repeated sequences in the viroid genome. This is the first report of SSR loci in viroids, and our study could be helpful in understanding the structure and evolution of viroid genomes. PMID:24649400
ERIC Educational Resources Information Center
Economou, A.; Tzanavaras, P. D.; Themelis, D. G.
2005-01-01
The sequential-injection analysis (SIA) is an approach to sample handling that enables the automation of manual wet-chemistry procedures in a rapid, precise and efficient manner. The experiments using SIA fits well in the course of Instrumental Chemical Analysis and especially in the section of Automatic Methods of analysis provided by chemistry…
A Model of Resource Allocation in Public School Districts: A Theoretical and Empirical Analysis.
ERIC Educational Resources Information Center
Chambers, Jay G.
This paper formulates a comprehensive model of resource allocation in a local public school district. The theoretical framework specified could be applied equally well to any number of local public social service agencies. Section 1 develops the theoretical model describing the process of resource allocation. This involves the determination of the…
Conflicts of Interest during Contact Investigations: A Game-Theoretic Analysis
Enanoria, Wayne T.; Porco, Travis C.
2014-01-01
The goal of contact tracing is to reduce the likelihood of transmission, particularly to individuals who are at greatest risk for developing complications of infection, as well as identifying individuals who are in need of medical treatment of other interventions. In this paper, we develop a simple mathematical model of contact investigations among a small group of individuals and apply game theory to explore conflicts of interest that may arise in the context of perceived costs of disclosure. Using analytic Kolmogorov equations, we determine whether or not it is possible for individual incentives to drive noncooperation, even though cooperation would yield a better group outcome. We found that if all individuals have a cost of disclosure, then the optimal individual decision is to simply not disclose each other. With further analysis of (1) completely offsetting the costs of disclosure and (2) partially offsetting the costs of disclosure, we found that all individuals disclose all contacts, resulting in a smaller basic reproductive number and an alignment of individual and group optimality. More data are needed to understand decision making during outbreak investigations and what the real and perceived costs are. PMID:24982688
Haucke, Florian
2010-11-01
Radon is a naturally occurring inert radioactive gas found in soils and rocks that can accumulate in dwellings, and is associated with an increased risk of lung cancer. This study aims to analyze the cost effectiveness of different intervention strategies to reduce radon concentrations in existing German dwellings. The cost effectiveness analysis (CEA) was conducted as a scenario analysis, where each scenario represents a specific regulatory regime. A decision theoretic model was developed, which reflects accepted recommendations for radon screening and mitigation and uses most up-to-date data on radon distribution and relative risks. The model was programmed to account for compliance with respect to the single steps of radon intervention, as well as data on the sensitivity/specificity of radon tests. A societal perspective was adopted to calculate costs and effects. All scenarios were calculated for different action levels. Cost effectiveness was measured in costs per averted case of lung cancer, costs per life year gained and costs per quality adjusted life year (QALY) gained. Univariate and multivariate deterministic and probabilistic sensitivity analyses (SA) were performed. Probabilistic sensitivity analyses were based on Monte Carlo simulations with 5000 model runs. The results show that legal regulations with mandatory screening and mitigation for indoor radon levels >100 Bq/m(3) are most cost effective. Incremental cost effectiveness compared to the no mitigation base case is 25,181 euro (95% CI: 7371 euro-90,593 euro) per QALY gained. Other intervention strategies focussing primarily on the personal responsibility for screening and/or mitigative actions show considerably worse cost effectiveness ratios. However, targeting radon intervention to radon-prone areas is significantly more cost effective. Most of the uncertainty that surrounds the results can be ascribed to the relative risk of radon exposure. It can be concluded that in the light of
NASA Technical Reports Server (NTRS)
Hess, R. A.; Wheat, L. W.
1975-01-01
A control theoretic model of the human pilot was used to analyze a baseline electronic cockpit display in a helicopter landing approach task. The head down display was created on a stroke written cathode ray tube and the vehicle was a UH-1H helicopter. The landing approach task consisted of maintaining prescribed groundspeed and glideslope in the presence of random vertical and horizontal turbulence. The pilot model was also used to generate and evaluate display quickening laws designed to improve pilot vehicle performance. A simple fixed base simulation provided comparative tracking data.
NASA Technical Reports Server (NTRS)
Henderson, R. A.; Schrag, R. L.
1986-01-01
A summary of modeling the electrical system aspects of a coil and metal target configuration resembling a practical electro-impulse deicing (EIDI) installation, and a simple circuit for providing energy to the coil, was presented. The model was developed in sufficient theoretical detail to allow the generation of computer algorithms for the current in the coil, the magnetic induction on both surfaces of the target, the force between the coil and target, and the impulse delivered to the target. These algorithms were applied to a specific prototype EIDI test system for which the current, magnetic fields near the target surfaces, and impulse were previously measured.
Simple proteomics data analysis in the object-oriented PowerShell.
Mohammed, Yassene; Palmblad, Magnus
2013-01-01
Scripting languages such as Perl and Python are appreciated for solving simple, everyday tasks in bioinformatics. A more recent, object-oriented command shell and scripting language, Windows PowerShell, has many attractive features: an object-oriented interactive command line, fluent navigation and manipulation of XML files, ability to consume Web services from the command line, consistent syntax and grammar, rich regular expressions, and advanced output formatting. The key difference between classical command shells and scripting languages, such as bash, and object-oriented ones, such as PowerShell, is that in the latter the result of a command is a structured object with inherited properties and methods rather than a simple stream of characters. Conveniently, PowerShell is included in all new releases of Microsoft Windows and therefore already installed on most computers in classrooms and teaching labs. In this chapter we demonstrate how PowerShell in particular allows easy interaction with mass spectrometry data in XML formats, connection to Web services for tools such as BLAST, and presentation of results as formatted text or graphics. These features make PowerShell much more than "yet another scripting language." PMID:23666736
PS-Analysis Of COSMO SAR Data Stacks Through A Fast And Simple Technique
NASA Astrophysics Data System (ADS)
Riva, Davide; D'Aria, Davide; Giudici, Davide; Guarnieri, Andrea Monti; Recchia, Andrea; Tagliani, Nicolas; Tebaldini, Stefano; Mancon, Simone
2012-01-01
This paper shows the results obtained with a Persistent Scatterers analysis over an X-band satellite interferometric dataset, acquired by three sensors of the COSMO SKYMED constellation over Milan, Italy. The accurate Persistent Scatterers analysis technique that leads to the estimation of the PS velocity, phase and displacement is briefly introduced. The PS analysis method performs the estimation by exploiting the differential atmospheric correction of the phases and then estimating the velocity through DFT.
Watts, C.A.
1993-09-01
In this dissertation the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas is investigated. To properly assess this possibility, data from both numerical simulations and experiment are analyzed. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos in the data. These tools include phase portraits and Poincare sections, correlation dimension, the spectrum of Lyapunov exponents and short term predictability. In addition, nonlinear noise reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are the DEBS code, which models global RFP dynamics, and the dissipative trapped electron mode (DTEM) model, which models drift wave turbulence. Data from both simulations show strong indications of low dimensional chaos and simple determinism. Experimental date were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low dimensional chaos or low simple determinism. Moreover, most of the analysis tools indicate the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system.
Design, analysis and validation of a simple dynamic model of a submerged membrane bioreactor.
Pimentel, Guilherme A; Vande Wouwer, Alain; Harmand, Jérôme; Rapaport, Alain
2015-03-01
In this study, a simple dynamic model of a submerged membrane bioreactor (sMBR) is proposed, which would be suitable for process control. In order to validate the proposed model structure, informative data sets are generated using a detailed simulator built in a well-established environment, namely GPS-X. The model properties are studied, including equilibrium points, stability, and slow/fast dynamics (three different time scales). The existence of slow-fast dynamics is central to the development of a dedicated parameter estimation procedure. Finally, a nonlinear model predictive control is designed to illustrate the potential of the developed model within a model-based control structure. The problem of water treatment in a recirculating aquaculture system is considered as an application example. PMID:25528540
Functional multiplicity of motor molecules revealed by a simple kinetic analysis.
Lark, E; Omoto, C K; Schumaker, M F
1994-01-01
We present a simple analytical solution for a kinetic model of motor molecule function with multiple arms. This model has a rate of motion proportional to the probability that all arms in a complex are detached from the cytoskeleton and, therefore, we refer to it as obligate cooperativity. The model has the form: v = Vmax/(1 + q/S)n, where Vmax is the maximum velocity, the product nq is the effective Michaelis constant at high [ATP], and n is the number of arms. Values of n = 2 and n = 1 give good fits to the heavy meromyosin and myosin S1 sliding velocity data, respectively, consistent with the number of active sites. Despite the complexity of the eukaryotic axoneme, beat frequency data from Chlamydomonas wild-type and oda mutants are also fit by this model. PMID:7811925
NASA Astrophysics Data System (ADS)
Goyal, Roopali V.; Patel, H. M.
2015-09-01
Knowledge of residual chlorine concentration at various locations in drinking water distribution system is essential final check to the quality of water supplied to the consumers. This paper presents a methodology to find out the residual chlorine concentration at various locations in simple branch network by integrating the hydraulic and water quality model using first-order chlorine decay equation with booster chlorination nodes for intermittent water supply. The explicit equations are developed to compute the residual chlorine in network with a long distribution pipe line at critical nodes. These equations are applicable to Indian conditions where intermittent water supply is the most common system of water supply. It is observed that in intermittent water supply, the residual chlorine at farthest node is sensitive to water supply hours and travelling time of chlorine. Thus, the travelling time of chlorine can be considered to justify the requirement of booster chlorination for intermittent water supply.
Analysis of a Four-Station Doppler Tracking Method Using a Simple CW Beacon
NASA Technical Reports Server (NTRS)
Fricke, Clifford L.; Watkins, Carl W. L.
1961-01-01
A Doppler tracking method is presented in which a very small, simple CW beacon transmitter is used with four Doppler receiving stations to obtain the position and velocity of a space research vehicle. The exact transmitter frequency need not be known, but an initial position is required, and Doppler frequencies must be measured with extreme accuracy. The errors in the system are analyzed and general formulas are derived for position and velocity errors. The proper location of receiving stations is discussed, a rule for avoiding infinite errors is given, and error charts for ideal station configurations are presented. The effect of the index of refraction is also investigated. The system is capable of determining transmitter position within 1,000 feet at a range of 200 miles.
Pollock, G E; Heiderer, R
1979-10-01
The work of Kenyon and Nissenbaum on aldocyanoin microspheres was repeated and extended. It was determined that the microspheres contained amino acids and that specific amino acids could be incorporated into the microspheres by adding the requisite aldehyde or ketone precursor to the model mixture. Microsphere formation was found to be dependent on the availability of oxygen. Under anaerobic conditions of synthesis, no microspheres formed in the time allotted and the amino acid composition of the macromolecular material was simple. Microparticulate material synthesized by C. Folsome using a quenched spark technique was analyzed and found to contain amino acids that had a qualitative composition similar to both a Miller-Urey discharge and the Kenyon-Nissenbaum microspheres. PMID:501747
Isami, Shuhei; Sakamoto, Naoaki; Nishimori, Hiraku; Awazu, Akinori
2015-01-01
Simple elastic network models of DNA were developed to reveal the structure-dynamics relationships for several nucleotide sequences. First, we propose a simple all-atom elastic network model of DNA that can explain the profiles of temperature factors for several crystal structures of DNA. Second, we propose a coarse-grained elastic network model of DNA, where each nucleotide is described only by one node. This model could effectively reproduce the detailed dynamics obtained with the all-atom elastic network model according to the sequence-dependent geometry. Through normal-mode analysis for the coarse-grained elastic network model, we exhaustively analyzed the dynamic features of a large number of long DNA sequences, approximately ∼150 bp in length. These analyses revealed positive correlations between the nucleosome-forming abilities and the inter-strand fluctuation strength of double-stranded DNA for several DNA sequences. PMID:26624614
Improved analysis of simple sugars and galacturonic acid in hydrolyzed citrus waste
Technology Transfer Automated Retrieval System (TEKTRAN)
While the most accurate method for analysis of sugars in biomass is based on gas chromatography of trimethylsilane or alditol acetate derivitives of sugars, the derivation method is time consuming and laborious. In comparison, sample preparation for sugar analysis using liquid chromatography is a si...
NASA Astrophysics Data System (ADS)
Miyazaki, Ryoichi; Saruwatari, Hiroshi; Shikano, Kiyohiro
We propose a structure-generalized blind spatial subtraction array (BSSA), and the theoretical analysis of the amounts of musical noise and speech distortion. The structure of BSSA should be selected according to the application, i.e., a channelwise BSSA is recommended for listening but a conventional BSSA is suitable for speech recognition.
Nastran level 16 theoretical manual updates for aeroelastic analysis of bladed discs
NASA Technical Reports Server (NTRS)
Elchuri, V.; Smith, G. C. C.
1980-01-01
A computer program based on state of the art compressor and structural technologies applied to bladed shrouded disc was developed and made operational in NASTRAN Level 16. Aeroelastic analyses, modes and flutter. Theoretical manual updates are included.
Graph theoretical analysis indicates cognitive impairment in MS stems from neural disconnection
Van Schependom, Jeroen; Gielen, Jeroen; Laton, Jorne; D'hooghe, Marie B.; De Keyser, Jacques; Nagels, Guy
2014-01-01
Background The mechanisms underlying cognitive impairment in MS are still poorly understood. However, due to the specific pathology of MS, one can expect alterations in connectivity leading to physical and cognitive impairment. Aim In this study we aimed at assessing connectivity differences in EEG between cognitively impaired (CI) and cognitively preserved (CP) MS patients. We also investigated the influence of the measures used to construct networks. Methods We included 308 MS patients and divided them into two groups based on their cognitive score. Graph theoretical network analyses were conducted based on networks constructed using different connectivity measures, i.e. correlation, correlation in the frequency domain, coherence, partial correlation, the phase lag index and the imaginary part of coherency. The most commonly encountered network parameters were calculated and compared between the two groups using Wilcoxon's rank test. Clustering coefficients and path lengths were normalized to a randomized mean clustering coefficient and path length for each patient. False discovery rate was used to correct for the multiple comparisons and Cohen's d effect sizes are reported. Results Coherence analysis suggests that theta and delta connectivity is significantly smaller in cognitively impaired patients. Small-worldness differences are found in networks based on correlation, theta and delta coherence and correlation in the frequency domain. Modularity was related to age but not to cognition. Conclusion Cognitive deterioration in MS is a symptom that seems to be caused by neural disconnections, probably the white matter tracts connecting both hemispheres, and leads to a wide range in network differences which can be assessed by applying GTA to EEG data. In the future, these results may lead to cheaper and more objective assessments of cognitive impairment in MS. PMID:24567912
NASA Astrophysics Data System (ADS)
Ding, Xuanming; Zhang, Ting; Li, Ping; Cheng, Ke
2016-02-01
This paper aims to present a theoretical method to study the bearing performance of vertically loaded large-diameter pipe pile groups. The interactions between group piles result in different bearing performance of both a single pile and pile groups. Considering the pile group effect and the skin friction from both outer and inner soils, an analytical solution is developed to calculate the settlement and axial force in large-diameter pipe pile groups. The analytical solution was verified by centrifuge and field testing results. An extensive parametric analysis was performed to study the bearing performance of the pipe pile groups. The results reveal that the axial forces in group piles are not the same. The larger the distance from central pile, the larger the axial force. The axial force in the central pile is the smallest, while that in corner piles is the largest. The axial force on the top of the corner piles decreases while that in the central pile increases with increasing of pile spacing and decreasing of pile length. The axial force in side piles varies little with the variations of pile spacing, pile length, and shear modulus of the soil and is approximately equal to the average load shared by one pile. For a pile group, the larger the pile length is, the larger the influence radius is. As a result, the pile group effect is more apparent for a larger pile length. The settlement of pile groups decreases with increasing of the pile number in the group and the shear modulus of the underlying soil.
Theoretical hypervelocity ballistic limit for single or double plates using nonlinear modal analysis
NASA Technical Reports Server (NTRS)
Hui, David
1990-01-01
The original research on the use on nonlinear vibration technique to solve for the hypervelocity ballistic limit for double plates is examined. Such structure is commonly found in typical Space Station design where the incoming space or man-made debris would be fragmented upon hitting the outer plate (shield) and the subsequent impact on the main wall would result in a much reduced damge of the space station or spacecraft. The existing few theoretical impact equations do not agree well with each other. The existing computer code bumper used at NASA-Johnson Space Center appears to predict an unconservative ballistic limit when compared with experimental data where the velocity ranges from 3 km/s to 8 km/s. Such unconservative prediction is unacceptable from a practical safe design point of view. The bumper code is based on Wilkinson's (1968) paper and his equations have not been improved nor modified even though they are viewed with suspicion due to lack of agreement with experiments. To make matters worse, there is not another theory which is better than Wilkinson's equation and the designers are forced to use purely empirical Nysmith (1969) or semiempirical equations developed by Cour-Palais in 1969. The Cour-Palais equations were later modified empirically in 1989. The purpose of the present investigation is to examine the many assumptions of the Wilkinson equation. An attempt is made to present design charts based on the modified-Wilkinson equation so that the designer can get a feel of the ranges of the parameters which are of interest and discard a huge range of parameters, thus, significantly reducing the number of test shots required. The analysis is based on a solution of the governing nonlinear differential equations for a plate, assuming axisymmetric behavior using polar coordinates.
NASA Astrophysics Data System (ADS)
Roulier, S.; Jarvis, N.
2003-12-01
Macropore flow is a key factor for determining chemical transport in unsaturated soils, but the description of the complex processes involved in macropore flow requires several parameters that cannot be easily measured. Inverse modeling procedures are increasingly used for model calibration, because they are objective and reproducible. But this is only true when the problem is well-posed: an ill-posed problem leads to parameter nonuniqueness, and thus contributes to poor model performance, like error and/or uncertainty in model predictions. Factors linked to nonuniqueness are most often related to sensitivity issues and/or correlation among two or several parameters. This study focused on the use of inverse techniques to estimate parameters controlling macropore flow, transport, and transformation processes in the dual porosity/dual-permeability model of water flow and solute transport MACRO. MACRO was used together with the inverse modeling package SUFI. The Bayesian (global) approach followed by SUFI is stable, converging, and robust. Moreover, the procedure also predicts a posterior uncertainty domain for the estimated parameters. A theoretical study was carried out to test the inverse modeling tool SUFI/MACRO. Generated "dummy" data set were used for this purpose, representing transient leaching experiment for tracers and reactive solutes in small soil columns (20 cm height). General issues related to inverse modeling such as internal correlation and sensitivity were investigated, with the help of response surface analysis, as well as the influence of the choice of the goal function used in the inverse procedure. Attention was also focused on the most appropriate experimental design necessary for a reliable parameter estimation. The procedure was then applied to real data, obtained from tracer leaching experiments carried out on microlysimeters. Based on calculated model efficiencies, MACRO/SUFI gave good predictions of water movement and tracer transport. This
Lo, E.H. )
1993-09-20
Stereotactic radiosurgery is being increasingly used to treat intracranial arteriovenous malformations (AVMs). However, successful radiosurgery may involve latent periods of 1-2 years prior to AVM obliteration. This latent period include states of altered flow patterns that may not influence hemorrhage probabilities. The probability of hemorrhage is likely to be related to the degree of biomechanical stress across the AVM shunt walls. This paper describes a theoretical analysis of the altered hemodynamics and biomechanical stresses within AVM shunts post-radiosurgery. The mathematical model is comprised of linked flow compartments that represent the AVM and adjacent normal vasculature. As obliteration of the irradiated shunts occurs, changes in flow rates and pressure gradients are calculated based on first order fluid dynamics. Stress on the AVM shunt walls is calculated based on tangential forces due to intramural pressure. Two basic models are presented: a distribution of shunts with fixed thin walls subject to step-function obliteration, and a distribution of shunts subject to luminal obliteration from slowly thickening walls. Variations on these models are analyzed, including sequential, selective and random shunt obliteration, and uniform or Poisson distributions of shunt radii. Model I reveals that the range of pressure alterations in the radiosurgically-treated AVM include the possibility of transient increases in the total biomechanical stress within the shunt walls prior to obliteration. Model II demonstrates that uniform luminal narrowing via thickened walls should lead to reduced transmural stresses. The precise temporal pattern of AVM flow decrease and biomechanical stress reduction depends on the selection of shunts that are obliterated. 34 refs., 5 figs., 1 tab.
Environmental analysis of present and future fuels in 2D simple model marine gas tubines
NASA Astrophysics Data System (ADS)
El Gohary, M. Morsy
2013-12-01
Increased worldwide concerns about fossil fuel costs and effects on the environment lead many governments and scientific societies to consider the hydrogen as the fuel of the future. Many researches have been made to assess the suitability of using the hydrogen gas as fuel for internal combustion engines and gas turbines; this suitability was assessed from several viewpoints including the combustion characteristics, the fuel production and storage and also the thermodynamic cycle changes with the application of hydrogen instead of ordinary fossil fuels. This paper introduces the basic environmental differences happening when changing the fuel of a marine gas turbine from marine diesel fuel to gaseous hydrogen for the same power output. Environmentally, the hydrogen is the best when the CO2 emissions are considered, zero carbon dioxide emissions can be theoretically attained. But when the NOx emissions are considered, the hydrogen is not the best based on the unit heat input. The hydrogen produces 270% more NOx than the diesel case without any control measures. This is primarily due to the increased air flow rate bringing more nitrogen into the combustion chamber and the increased combustion temperature (10% more than the diesel case). Efficient and of course expensive NOx control measures are a must to control these emissions levels.
Deployment Analysis of a Simple Tape-Spring Hinge Using Probabilistic Methods
NASA Technical Reports Server (NTRS)
Lyle, Karen H.; Horta, Lucas G.
2012-01-01
Acceptance of new deployable structures architectures and concepts requires validated design methods to minimize the expense involved with technology validation flight testing. Deployable concepts for large lightweight spacecraft include booms, antennae, and masts. This paper explores the implementation of probabilistic methods in the design process for the deployment of a strain-energy mechanism, specifically a simple tape-spring hinge. Strain-energy mechanisms are attractive for deployment in very lightweight systems because they do not require the added mass and complexity associated with motors and controllers. However, designers are hesitant to include free deployment, strain-energy mechanisms because of the potential for uncontrolled behavior. In the example presented here, the tapespring cross-sectional dimensions have been varied and a target displacement during deployment has been selected as the design metric. Specifically, the tape-spring should reach the final position in the shortest time with the minimal amount of overshoot and oscillations. Surrogate models have been used to reduce computational expense. Parameter values to achieve the target response have been computed and used to demonstrate the approach. Based on these results, the application of probabilistic methods for design of a tape-spring hinge has shown promise as a means of designing strain-energy components for more complex space concepts.
NASA Astrophysics Data System (ADS)
Kubica, Aleksander; Yoshida, Beni
2014-03-01
We invent a novel real-space renormalization group (RG) scheme which accurately estimates correlation length exponents ν near criticality of quantum Ising and clock models in higher dimensions. The method, based on a recent proposal by Miyazaki et al., Phys. Rev. E 83, 051103 (2011), is remarkably simple (often analytical), grouping only a few spins into a block spin so that renormalized Hamiltonian has a closed form. A previous difficulty of spatial anisotropy and unwanted terms arising in higher-dimensional RG schemes is avoided by incorporating rotational invariance and internal Zq symmetries of the Hamiltonian. By applying this scheme to (2+1)-dim Ising model on a triangular lattice, we obtained ν = 0 . 6300 which is within statistical error of the current best Monte-Carlo result and ϕ4 theory estimation with seven-loop corrections. We also apply the scheme to higher-dimensional clock (Potts) models for which ordinary Monte-Carlo methods are not efficient due to suppression of quantum fluctuation in first-order phase transition.
Electrolyte transport across a simple epithelium. Steady-state and transient analysis.
Weinstein, A M; Stephenson, J L
1979-01-01
A simple transporting epithelium is represented as a cellular compartment, compliant in all dimensions, and a paracellular channel, of arbitrary shape, between well-stirred mucosal ans serosal baths. The equations for mass balance, Poiseuille flow, and the Nernst-Planck equation are used to describe the continuous behavior of the system along cell and channel, whereas passive transport across membranes is given by the relations of Kedem and Katchalsky. Time-dependent terms are retained to permit study of transient phenomena. Boundary conditions at the baths demand only mass conservation and specify no a priori estimates of the system variables. A numerical model containing Na+,K+,Cl-, and impermeant cellular anions is formulated with membrane parameters taken from the literature on Necturus gallbladder. The differential equations are represented as a finite difference scheme and solved using Newton's method. It appears that apical cellular NaCl cotransport is necessary to obtain a reasonable cell chloride concentration. Investigation of the osmolality of the transepithelial flow shows that at steady state a leaky epithelium cannot separate baths of substantially different tonicity, although this does not guarantee isotonic transport between equiosmolar media. Changes in bath pressure, application of transepithelial electrical potential, and simulation of ion-substitution experiments are performed to understand the role of membrane permeabilities in determining the dynamic behavior of the epithelium. PMID:233579
A simple separation method for downstream biochemical analysis of aquatic microbes.
Garrison, Cody E; Bochdansky, Alexander B
2015-04-01
In order to study the chemical composition of aquatic microbes it is necessary to obtain completely separated fractions of subpopulations. Size separation by filtration is usually unsuccessful because the smaller group of organisms contaminates the larger fractions due to being trapped on filter surfaces of nominally much larger pore sizes. Here we demonstrate that a simple sucrose density separation method allowed us to separate microorganisms of even subtle size differences and to determine their bulk biochemical composition (proteins, polysaccharides+nucleic acids, and lipids). Both autotrophs and heterotrophs (through anaplerotic pathways) were labeled with (14)C-bicarbonate for biochemical fractionation. We provided proof of concept that eukaryotic microbes could be cleanly separated from prokaryotes in cultures and in field samples, enabling detection of differences in their biochemical makeup. We explored methodological issues regarding separation mechanisms, fixation, and pre-concentration via tangential flow filtration of oligotrophic marine waters where abundances of microorganisms are comparably low. By selecting an appropriate centrifugal force, two processes (i.e., isopycnal and rate-zonal separation) can be exploited simultaneously resulting in finely-separated density fractions, which also resulted in size separation. Future applications of this method include exploration of the stoichiometric, biochemical and genetic differences among subpopulations of microbes in a wide variety of aquatic environments. PMID:25655777
NASA Astrophysics Data System (ADS)
Habte, Frezghi; Natarajan, Arutselvan; Paik, David S.; Gambhir, Sanjiv S.
2014-03-01
Cerenkov luminescence imaging (CLI) is an emerging cost effective modality that uses conventional small animal optical imaging systems and clinically available radionuclide probes for light emission. CLI has shown good correlation with PET for organs of high uptake such as kidney, spleen, thymus and subcutaneous tumors in mouse models. However, CLI has limitations for deep tissue quantitative imaging since the blue-weighted spectral characteristics of Cerenkov radiation attenuates highly by mammalian tissue. Large organs such as the liver have also shown higher signal due to the contribution of emission of light from a greater thickness of tissue. In this study, we developed a simple model that estimates the effective tissue attenuation coefficient in order to correct the CLI signal intensity with a priori estimated depth and thickness of specific organs. We used several thin slices of ham to build a phantom with realistic attenuation. We placed radionuclide sources inside the phantom at different tissue depths and imaged it using an IVIS Spectrum (Perkin-Elmer, Waltham, MA, USA) and Inveon microPET (Preclinical Solutions Siemens, Knoxville, TN). We also performed CLI and PET of mouse models and applied the proposed attenuation model to correct CLI measurements. Using calibration factors obtained from phantom study that converts the corrected CLI measurements to %ID/g, we obtained an average difference of less that 10% for spleen and less than 35% for liver compared to conventional PET measurements. Hence, the proposed model has a capability of correcting the CLI signal to provide comparable measurements with PET data.
Simple Fall Criteria for MEMS Sensors: Data Analysis and Sensor Concept
Ibrahim, Alwathiqbellah; Younis, Mohammad I.
2014-01-01
This paper presents a new and simple fall detection concept based on detailed experimental data of human falling and the activities of daily living (ADLs). Establishing appropriate fall algorithms compatible with MEMS sensors requires detailed data on falls and ADLs that indicate clearly the variations of the kinematics at the possible sensor node location on the human body, such as hip, head, and chest. Currently, there is a lack of data on the exact direction and magnitude of each acceleration component associated with these node locations. This is crucial for MEMS structures, which have inertia elements very close to the substrate and are capacitively biased, and hence, are very sensitive to the direction of motion whether it is toward or away from the substrate. This work presents detailed data of the acceleration components on various locations on the human body during various kinds of falls and ADLs. A two-degree-of-freedom model is used to help interpret the experimental data. An algorithm for fall detection based on MEMS switches is then established. A new sensing concept based on the algorithm is proposed. The concept is based on employing several inertia sensors, which are triggered simultaneously, as electrical switches connected in series, upon receiving a true fall signal. In the case of everyday life activities, some or no switches will be triggered resulting in an open circuit configuration, thereby preventing false positive. Lumped-parameter model is presented for the device and preliminary simulation results are presented illustrating the new device concept. PMID:25006997
NASA Astrophysics Data System (ADS)
West, Jay A.; Hukari, Kyle W.; Renzi, Ronald F.; Patel, Kamlesh
2004-12-01
Rapid identification of viral and bacterial species is dependent of the ability to manipulate biological agents into a form where they are directly analyzed. Many of these species of interest, such as bacterial spores, are inherently hearty and very difficult to lyse or solubilize. Standard protocols for spore inactivation include, chemical treatment, sonication, pressure and thermal lysis. While these protocols are effective for the inactivation of these agents they are less well suited for sample preparation for analysis using capillary electrophoresis techniques. In order to overcome this difficulty we fabricated a simple capillary device to perform thermal lysis of vegatative bacterial cells and bacterial spores. Using an ethylene glycol buffer to super heat bacterial spores we were able to perform rapid flow through lysis and solubilzation of these agents. This device was then coupled to a sample preparation station for on-line fluorescamine dye lableling and buffer exchange for direct analysis using a miniaturized capillary electrophoresis instrument. Using this integrated device were we enabled to perform sample lysis, labeling and protein fingerprint analysis of vegatative bacterial cells, bacterial spores and viruses in less than 10 minutes. The described device is simple, inexpensive and easily integratable with various microfluidic devices.
Simple non-invasive analysis of embryonic stem cell-derived cardiomyocytes beating in vitro
NASA Astrophysics Data System (ADS)
Radaszkiewicz, Katarzyna Anna; Sýkorová, Dominika; Karas, Pavel; Kudová, Jana; Kohút, Lukáš; Binó, Lucia; Večeřa, Josef; Víteček, Jan; Kubala, Lukáš; Pacherník, Jiří
2016-02-01
The analysis of digital video output enables the non-invasive screening of various active biological processes. For the monitoring and computing of the beating parameters of cardiomyocytes in vitro, CB Analyser (cardiomyocyte beating analyser) software was developed. This software is based on image analysis of the video recording of beating cardiomyocytes. CB Analyser was tested using cardiomyocytes derived from mouse embryonic stem cells at different stages of cardiomyogenesis. We observed that during differentiation (from day 18), the beat peak width decreased, which corresponded to the increased speed of an individual pulse. However, the beating frequency did not change. Further, the effects of epinephrine modulating mature cardiomyocyte functions were tested to validate the CB Analyser analysis. In conclusion, data show that CB Analyser is a useful tool for evaluating the functions of both developing and mature cardiomyocytes under various conditions in vitro.
Simple Analysis Used in Diagnosis and Follow-up of Schizophrenic Patients (Patent)
Nour El-Dien, Faten A.; El-Nahas, Reham G.; El-Nahas, Ahmed G.
2006-01-01
Dopamine acts as neurotransmitter in the central and peripheral sympathetic nervous system. Determination of dopamine (DO) was performed by spectrophotometric analysis depending on the formation of new colored compound. The proposed procedure was efficient in quantitative determination of DO as pure material in pharmaceutical preparations and in urine samples. DO concentration in urine sample of patient confirms the affection with schizophrenia and the proposed procedure was used to facilitate diagnosis and followup of schizophrenic patients. It is recommended to apply the proposed procedures as routine analysis in pharmaceutical companies for quality control and in analytical laboratories to diagnose and follow up schizophrenia. PMID:17671624
The Drosophila larval visual system: high-resolution analysis of a simple visual neuropil.
Sprecher, Simon G; Cardona, Albert; Hartenstein, Volker
2011-10-01
The task of the visual system is to translate light into neuronal encoded information. This translation of photons into neuronal signals is achieved by photoreceptor neurons (PRs), specialized sensory neurons, located in the eye. Upon perception of light the PRs will send a signal to target neurons, which represent a first station of visual processing. Increasing complexity of visual processing stems from the number of distinct PR subtypes and their various types of target neurons that are contacted. The visual system of the fruit fly larva represents a simple visual system (larval optic neuropil, LON) that consists of 12 PRs falling into two classes: blue-senstive PRs expressing Rhodopsin 5 (Rh5) and green-sensitive PRs expressing Rhodopsin 6 (Rh6). These afferents contact a small number of target neurons, including optic lobe pioneers (OLPs) and lateral clock neurons (LNs). We combine the use of genetic markers to label both PR subtypes and the distinct, identifiable sets of target neurons with a serial EM reconstruction to generate a high-resolution map of the larval optic neuropil. We find that the larval optic neuropil shows a clear bipartite organization consisting of one domain innervated by PRs and one devoid of PR axons. The topology of PR projections, in particular the relationship between Rh5 and Rh6 afferents, is maintained from the nerve entering the brain to the axon terminals. The target neurons can be subdivided according to neurotransmitter or neuropeptide they use as well as the location within the brain. We further track the larval optic neuropil through development from first larval instar to its location in the adult brain as the accessory medulla. PMID:21781960
The Drosophila larval visual system: high-resolution analysis of a simple visual neuropil
Sprecher, Simon G.; Cardona, Albert; Hartenstein, Volker
2012-01-01
The task of the visual system is to translate light into neuronal encoded information. This translation of photons into neuronal signals is achieved by photoreceptor neurons (PRs), specialized sensory neurons, located in the eye. Upon perception of light the PRs will send a signal to target neurons, which represent a first station of visual processing. Increasing complexity of visual processing stems from the number of distinct PR-subtypes and their various types of target neurons that are contacted. The visual system of the fruit fly larva represents a simple visual system (larval optic neuropil, LON) that consists of 12 PRs falling into two classes: blue-senstive PRs expressing Rhodopsin 5 (Rh5) and green-sensitive PRs expressing Rhodopsin 6 (Rh6). These afferents contact a small number of target neurons, including optic lobe pioneers (OLPs) and lateral clock neurons (LNs). We combine the use of genetic markers to label both PR-subtypes and the distinct, identifiable sets of target neurons with a serial EM reconstruction to generate a high-resolution map of the larval optic neuropil. We find that the larval optic neuropil shows a clear bipartite organization consisting of one domain innervated by PRs and one devoid of PR axons. The topology of PR projections, in particular the relationship between Rh5 and Rh6 afferents, is maintained from the nerve entering the brain to the axon terminals. The target neurons can be subdivided according to neurotransmitter or neuropeptide they use as well as the location within the brain. We further track the larval optic neuropil through development from first larval instar to its location in the adult brain as the accessory medulla. PMID:21781960
Quantitative Analysis of Organic Compounds: A Simple and Rapid Method for Use in Schools
ERIC Educational Resources Information Center
Schmidt, Hans-Jurgen
1973-01-01
Describes the procedure for making a quantitative analysis of organic compounds suitable for secondary school chemistry classes. Using the Schoniger procedure, the organic compound, such as PVC, is decomposed in a conical flask with oxygen. The products are absorbed in a suitable liquid and analyzed by titration. (JR)
Chen, Jin; Tang, Fei; Guo, Cheng'an; Huo, Xinming; Zhang, Sichun; Wang, Xiaohao
2016-07-01
Interlayer spray is proposed as a convenient ionization source for direct analysis by mass spectrometry. Two slices of non-absorbent substrate hold the liquid sample to form a sandwich structure. By applying a high voltage to the sample, spray is generated at the tip of the substrate. The sampling procedure can be operated easily in an open condition and the spray is processed in a semi-enclosed condition, which leads to a relatively stable process. An ultralow amount (<2 μL) of the liquid sample can be analyzed without dilution, which ensures that the natural concentration and properties of the target are maintained. Less influence from the substrate is achieved compared with the spray methods based on porous absorbent materials, which results in a sensitivity enhancement of large molecule samples. It is demonstrated that the interlayer spray is applicable for the analysis of various compounds, including therapeutic drugs, peptides, and proteins. Good linearity can be obtained at a concentration as low as 50 ng/mL in the quantitative analysis for imatinib. We also show the ability to identify the chemical residuals on surfaces with high sensitivity by the "wipe-spray" method, which is useful for the fast screening of illicit substances. Interlayer spray working with mass spectrometry provides a promising method for direct analysis in an ambient environment. Graphical Abstract The schematic of the interlayer spray ionization source. PMID:27173393
Starr: Simple Tiling ARRay analysis of Affymetrix ChIP-chip data
2010-01-01
Background Chromatin immunoprecipitation combined with DNA microarrays (ChIP-chip) is an assay used for investigating DNA-protein-binding or post-translational chromatin/histone modifications. As with all high-throughput technologies, it requires thorough bioinformatic processing of the data for which there is no standard yet. The primary goal is to reliably identify and localize genomic regions that bind a specific protein. Further investigation compares binding profiles of functionally related proteins, or binding profiles of the same proteins in different genetic backgrounds or experimental conditions. Ultimately, the goal is to gain a mechanistic understanding of the effects of DNA binding events on gene expression. Results We present a free, open-source R/Bioconductor package Starr that facilitates comparative analysis of ChIP-chip data across experiments and across different microarray platforms. The package provides functions for data import, quality assessment, data visualization and exploration. Starr includes high-level analysis tools such as the alignment of ChIP signals along annotated features, correlation analysis of ChIP signals with complementary genomic data, peak-finding and comparative display of multiple clusters of binding profiles. It uses standard Bioconductor classes for maximum compatibility with other software. Moreover, Starr automatically updates microarray probe annotation files by a highly efficient remapping of microarray probe sequences to an arbitrary genome. Conclusion Starr is an R package that covers the complete ChIP-chip workflow from data processing to binding pattern detection. It focuses on the high-level data analysis, e.g., it provides methods for the integration and combined statistical analysis of binding profiles and complementary functional genomics data. Starr enables systematic assessment of binding behaviour for groups of genes that are alingned along arbitrary genomic features. PMID:20398407
NASA Astrophysics Data System (ADS)
Mansoura, S. A.; Benard, P.; Morvan, B.; Maréchal, P.; Hladky-Hennion, A.-C.; Dubus, B.
2015-11-01
In this paper, a theoretical and experimental study of the electric impedance of a piezoelectric plate connected to a negative capacitance is performed in the MHz frequency range. The negative capacitance is realized with a circuit using current conveyors (CCII+). This circuit allows us to achieve important values of negative capacitance, of the same order of the static capacitance of the piezoelectric plate studied. Mason’s model is considered for the theoretical characterization of the piezoelectric plate connected to the negative capacitance circuit. The experimental results show a large tunability of the frequency of the piezoelectric parallel resonance over a range of 1.1 MHz to 1.28 MHz. Moreover, according to the value of the negative capacitance, the effective electromechanical coupling factor of the piezoelectric plate is evaluated. With a very good agreement with the theoretical estimation, an increase of approximately 50% of the effective electromechanical coupling factor is experimentally measured.
Li, Junhua; Sun, Runguang; Hao, Changchun; He, Guangxiao; Zhang, Lei; Wang, Juan
2015-10-01
Cytochrome c (Cyt c) is an essential component of the inner mitochondrial respiratory chain because of its function of transferring electrons. The feature is closely related to the interaction between Cyt c and membrane lipids. We used Langmuir-Blodgett monolayer technique combined with AFM to study the interaction of Cyt c with lipid monolayers at air-buffer interface. In our work, by comparing the mixed Cyt c-anionic (DPPS) and Cyt c-zwitterionic (DPPC/DPPE) monolayers, the adsorption capacity of Cyt c on lipid monolayers is DPPS>DPPE>DPPC, which is attributed to their different headgroup structures. π-A isothermal data show that Cyt c (v=2.5 μL) molecules are at maximum adsorption quantity on lipid monolayer. Moreover, Cyt c molecules would form aggregations and drag some lipids with them into subphase if the protein exceeds the maximum adsorption quantity. π-T curve indicates that it takes more time for Cyt c molecular conformation to rearrange on DPPE monolayer than on DPPC. The compressibility study reveals that the adsorption or intermolecular aggregation of Cyt c molecules on lipid monolayer will change the membrane fluidization. In order to quantitatively estimate Cyt c molecular adsorption properties on lipid monolayers, we fit the experimental isotherm with a simple surface state equation. A theoretical model is also introduced to analyze the liquid expanded (LE) to liquid condensed (LC) phase transition of DPPC monolayer. The results of theoretical analysis are in good agreement with the experiment. PMID:26071844
Tong, Glenna So-Ming; Che, Chi-Ming
2009-07-20
We herein report a theoretical analysis based on a density functional theory/time-dependent density functional theory (DFT/TDDFT) approach to understand the different phosphorescence efficiencies of a family of cyclometalated platinum(II) complexes: [Pt(NCN)Cl] (1; NCN = 1,3-bis(2-pyridyl)phenyl(-)), [Pt(CNN)Cl] (2; CNN = 6-phenyl-2,2'-bipyridyl(-)), [Pt(CNC)(CNPh)] (3; CNC = 2,6-diphenylpyridyl(2-)), [Pt(R-CNN)Cl] (4; R-CNN = 3-(6'-(2''-naphthyl)-2'-pyridyl)isoquinolinyl(-)), and [Pt(R-CNC)(CNPh)] (5; R-CNC = 2,6-bis(2'-naphthyl)pyridyl(2-)). By considering both the spin-orbit coupling (SOC) and the electronic structures of these complexes at their respective optimized singlet ground (S(0)) and first triplet (T(opt)(1)) excited states, we were able to rationalize the experimental findings that 1) 1 is a strong emitter while its isomer 2 is only weakly emissive in CH(2)Cl(2) solution at room temperature; 2) although the cyclometalated ligand of 3 has a higher ligand-field strength than that of 1, 3 is nonemissive in CH(2)Cl(2) solution at 298 K; and 3) extension of pi conjugation at the lateral aryl rings of the cyclometalated ligands of 2 and 3 to give 4 and 5, respectively, leads to increased emission quantum yields under the same conditions. We found that Jahn-Teller and pseudo-Jahn-Teller effects are operative in complexes 2 and 3, respectively, on going from the optimized S(0) ground state to the optimized T(opt)(1) excited state, and thus lead to large excited-state structural distortions and hence fast nonradiative decay. Furthermore, a strong-field ligand may push the two different occupied d orbitals so far apart that the SOC effect is small and the radiative decay rate is slow. This work is an example of electronic-structure-driven tuning of the phosphorescence efficiency, and the DFT/TDDFT approach is demonstrated to be a versatile tool for the design of phosphorescent materials with target characteristics. PMID:19544517
Formation of different types of compaction bands: Theoretical analysis and numerical models
NASA Astrophysics Data System (ADS)
Chemenda, A. I.
2010-12-01
The onset and evolution of tabular compaction bands is studied based on the discontinuous bifurcation analysis and finite-difference simulations. In numerical models, the bands are initiated as constitutive instabilities resulting from the deformation bifurcation. Band spacing, length and aspect strongly depend on the constitutive parameters and particularly on the hardening modulus h, both spacing and length rapidly increasing with h. Compaction banding is only possible when h lies within certain limits h_min and h_max defined by other parameters. If h > h_max, the deformation localisation is either impossible at all or occurs in the form of shear banding, depending on the parameters. The transition from shear to compaction banding is gradual and corresponds to the formation of crooked or zigzag bands similar to those obtained in the experimental rock tests. These bands are very dense and have small wavelength when h approaches h_min. On the other hand, when h approaches h_max and at h > h_max the deformation localisation is impossible, the forming compaction bands are linear and long. After the initiation of these bands (from deformation bifurcation) some of them are dying, while others continue a post-bifurcation evolution accumulating the inelastic deformation/damage and compressive stress at their tips. This stress, however, does not exceed 0.1% of the background value. Starting from some stage, the bands begin to propagate similarly to cracks. The propagation then slows down simultaneously with the beginning of bands’ thickening that occurs due to the incorporation of not yet compacted material at the band flanks. Then the propagation practically stops and the bands undergo only the heterogeneous thickening, maximal in the middle of the band and reducing toward its tips. This scenario obtained directly in the numerical models (without any specific hypotheses about the propagation mechanism) appears more complicated than what can be expected from the LEFM
NASA Technical Reports Server (NTRS)
Agarwal, G. C.; Osafo-Charles, F.; Oneill, W. D.; Gottlieb, G. L.
1982-01-01
Time series analysis is applied to model human operator dynamics in pursuit and compensatory tracking modes. The normalized residual criterion is used as a one-step analytical tool to encompass the processes of identification, estimation, and diagnostic checking. A parameter constraining technique is introduced to develop more reliable models of human operator dynamics. The human operator is adequately modeled by a second order dynamic system both in pursuit and compensatory tracking modes. In comparing the data sampling rates, 100 msec between samples is adequate and is shown to provide better results than 200 msec sampling. The residual power spectrum and eigenvalue analysis show that the human operator is not a generator of periodic characteristics.
The limitations of simple gene set enrichment analysis assuming gene independence.
Tamayo, Pablo; Steinhardt, George; Liberzon, Arthur; Mesirov, Jill P
2016-02-01
Since its first publication in 2003, the Gene Set Enrichment Analysis method, based on the Kolmogorov-Smirnov statistic, has been heavily used, modified, and also questioned. Recently a simplified approach using a one-sample t-test score to assess enrichment and ignoring gene-gene correlations was proposed by Irizarry et al. 2009 as a serious contender. The argument criticizes Gene Set Enrichment Analysis's nonparametric nature and its use of an empirical null distribution as unnecessary and hard to compute. We refute these claims by careful consideration of the assumptions of the simplified method and its results, including a comparison with Gene Set Enrichment Analysis's on a large benchmark set of 50 datasets. Our results provide strong empirical evidence that gene-gene correlations cannot be ignored due to the significant variance inflation they produced on the enrichment scores and should be taken into account when estimating gene set enrichment significance. In addition, we discuss the challenges that the complex correlation structure and multi-modality of gene sets pose more generally for gene set enrichment methods. PMID:23070592
Following the enzymatic digestion of chondroitin sulfate by a simple GPC analysis.
Silva, Carla; Novoa-Carballal, Ramon; Reis, Rui L; Pashkuleva, Iva
2015-07-23
We describe the use of gel permeation chromatography (GPC) setup with four size exclusion columns for analysis of enzymatically digested glycosaminoglycans (GAGs). This setup provides information about the molecular weight (Mw) and concentration of all species (low and high Mw) present in the digests in a single measurement. The data about the fraction with high Mw (often omitted in the analysis of GAG digests) provide direct evidence about the mechanisms of action of the enzymes. We proved the feasibility of this methodology by applying it to chondroitin sulfate (CS) substrates with different molecular weight and sulfation pattern and using different enzymes (hyaluronidase and chondroitinase). NMR analysis of the obtained digests fractionated by ultrafiltration confirmed the results obtained by GPC setup and reveal further details about the degradation mechanisms: (i) both enzymes preferentially attack 4-sulfated chondroitin and (ii) additionally to the well documented endolytic activity of hyaluronidase we also observed a low lyase activity for this enzyme reflected in the detected minor exolytic breakage. Finally, we demonstrate that CS with medium molecular weight (12-60kDa) which is sulfated mainly at 6-position can be obtained in good yields by enzymatic digestion and following ultrafiltration. PMID:26231907
GPR-Analyzer: a simple tool for quantitative analysis of hierarchical multispecies microarrays.
Dittami, Simon M; Edvardsen, Bente
2013-10-01
Monitoring of marine microalgae is important to predict and manage harmful algae blooms. It currently relies mainly on light-microscopic identification and enumeration of algal cells, yet several molecular tools are currently being developed to complement traditional methods. MIcroarray Detection of Toxic ALgae (MIDTAL) is an FP7-funded EU project aiming to establish a hierarchical multispecies microarray as one of these tools. Prototype arrays are currently being tested with field samples, yet the analysis of the large quantities of data generated by these arrays presents a challenge as suitable analysis tools or protocols are scarce. This paper proposes a two-part protocol for the analysis of the MIDTAL and other hierarchical multispecies arrays: Signal-to-noise ratios can be used to determine the presence or absence of signals and to identify potential false-positives considering parallel and hierarchical probes. In addition, normalized total signal intensities are recommended for comparisons between microarrays and in order to relate signals for specific probes to cell concentrations using external calibration curves. Hybridization- and probe-specific detection limits can be calculated to help evaluate negative results. The suggested analyses were implemented in "GPR-Analyzer", a platform-independent and graphical user interface-based application, enabling non-specialist users to quickly and quantitatively analyze hierarchical multispecies microarrays. It is available online at http://folk.uio.no/edvardse/gpranalyzer . PMID:22767354
PS-analysis of InSAR data stacks through a quick and simple approach
NASA Astrophysics Data System (ADS)
Riva, D.; D'Aria, D.; Monti Guarnieri, A.; Giudici, D.; Scagliola, M.
2012-12-01
PS InSAR is a very useful remote-sensing technique for detecting and monitoring line-of-sight (uplift and subsidence) surface deformations both in rural zones and urbanized area. In this paper, an accurate PS analysis technique is described. This technique leads to the estimate of the PS differential velocity, phase and displacement starting from a SAR interferometric dataset. PS differential velocity can be useful to analyze the deformation of chosen sites in order to detect unexpected terrain movements and identify hazard risks in particular in urbanized areas. The technique is an original implementation of the Persistent Scatterers analysis, based on the correction of the atmospheric disturbance through the estimation of a differential velocity field to be integrated and removed from the original interferograms. This core step is important as it allows to obtain the atmospheric corrected phases while avoiding the direct estimation of the phase itself. The procedure exploits the initial set of PS candidates to estimate the spatial gradient of the phase and, after this step, the differential velocity field. Being this field estimated on the spatial gradient of the phases, it is smooth and can be unwrapped leading to a straight velocity analysis. The atmospheric phase screen (APS) is interpolated over all the pixels, allowing the densification of the PS set in a second iteration. The APS can be useful to enhance tomographic studies in chosen areas, reducing errors introduced in the InSAR data stacks by atmospheric disturbance. Knowing the location of each PS, its velocity and tomographic information, dynamic 3D city models can be generated. The proposed approach allows to analyze SAR interferometric datasets belonging to sensors with different resolutions. In this paper the result of processing COSMO SKYMED high resolution Stripmap data (about 3 x 3 meters resolution) provided by the Politecnico of Milan in the frame of the ASI-AO #1080 "SAR data Calibration and
NASA Astrophysics Data System (ADS)
Mikeš, Daniel
2010-05-01
erroneous assumptions and do not solve the very fundamental issue that lies at the base of the problem. This problem is straighforward and obvious: a sedimentary system is inherently four-dimensional (3 spatial dimensions + 1 temporal dimension). Any method using an inferior number or dimensions is bound to fail to describe the evolution of a sedimentary system. It is indicative of the present day geological world that such fundamental issues be overlooked. The only reason for which one can appoint the socalled "rationality" in todays society. Simple "common sense" leads us to the conclusion that in this case the empirical method is bound to fail and the only method that can solve the problem is the theoretical approach. Reasoning that is completely trivial for the traditional exact sciences like physics and mathematics and applied sciences like engineering. However, not for geology, a science that was traditionally descriptive and jumped to empirical science, skipping the stage of theoretical science. I argue that the gap of theoretical geology is left open and needs to be filled. Every discipline in geology lacks a theoretical base. This base can only be filled by the theoretical/inductive approach and can impossibly be filled by the empirical/deductive approach. Once a critical mass of geologists realises this flaw in todays geology, we can start solving the fundamental problems in geology.
A Preliminary Theoretical Analysis of a Research Experience for Undergraduates Community Model
ERIC Educational Resources Information Center
Castillo-Garsow, Carlos; Castillo-Chavez, Carlos; Woodley, Sherry
2013-01-01
The Mathematical and Theoretical Biology Institute (MTBI) is a successful summer research experience for undergraduates, with a strong record of mentoring Ph.D. graduates, particularly, underrepresented minority students. However, the MTBI program was designed for education in research, not for research in education, and the mechanisms of the…
ERIC Educational Resources Information Center
Feldner, Matthew T.; Monson, Candice M.; Friedman, Matthew J.
2007-01-01
Although efforts to prevent posttraumatic stress disorder (PTSD) have met with relatively limited success, theoretically driven preventive approaches with promising efficacy are emerging. The current article critically reviews investigations of PTSD prevention programs that target persons at risk for being exposed to a traumatic event or who have…
Adjectives That Aren't: An ERP-Theoretical Analysis of Adjectives in Spanish
ERIC Educational Resources Information Center
Bartlett, Laura B.
2013-01-01
This thesis investigates the syntactic status of adjectives in Spanish through a crossdisciplinary perspective, incorporating methodologies from both theoretical linguistics and neurolinguistics, specifically, event-related potentials (ERPs). It presents conflicting theories about the syntax of adjectives and explores the ways that the processing…
ERIC Educational Resources Information Center
Newman, Tim A.
2012-01-01
This study described the current state of principal salaries in South Carolina and compared the salaries of similar size schools by specific report card performance and demographic variables. Based on the findings, theoretical models were proposed, and comparisons were made with current salary data. School boards, human resource personnel and…
An Analysis of Enabling School Structure: Theoretical, Empirical, and Research Considerations
ERIC Educational Resources Information Center
Sinden, James E.; Hoy, Wayne K.; Sweetland, Scott R.
2004-01-01
The construct of enabling school structure is empirically analyzed in this qualitative study of high schools. First, the theoretical underpinning of enabling school structure is developed. Then, six high schools, which were determined to have enabling structures in a large quantitative study of Ohio schools, were analyzed in depth using…
Falling Chains as Variable-Mass Systems: Theoretical Model and Experimental Analysis
ERIC Educational Resources Information Center
de Sousa, Celia A.; Gordo, Paulo M.; Costa, Pedro
2012-01-01
In this paper, we revisit, theoretically and experimentally, the fall of a folded U-chain and of a pile-chain. The model calculation implies the division of the whole system into two subsystems of variable mass, allowing us to explore the role of tensional contact forces at the boundary of the subsystems. This justifies, for instance, that the…
Skill Learning as a Concept in Life-Span Developmental Psychology: An Action Theoretic Analysis.
ERIC Educational Resources Information Center
Frese, M.; Stewart, J.
1984-01-01
An action theoretic account of skill learning and skill use is offered as a useful heuristic for life-span developmental psychology. The version presented is one that is particularly prominent in industrial psychology in the German-speaking countries. (Author/RH)
A Historical Analysis of Academic Development Using the Theoretical Lens of Pierre Bourdieu
ERIC Educational Resources Information Center
Kloot, Bruce Charles
2015-01-01
This paper provides a history of academic development by examining how a South African institution coped with the potent social forces confronting it before the collapse of apartheid. Theoretically, it draws on the framework of Pierre Bourdieu and engages with a paper written a decade ago by Naidoo, who also used Bourdieu to understand…
Exhaled breath analysis, a simple tool to study the pathophysiology of obstructive sleep apnoea.
Bikov, Andras; Hull, James H; Kunos, Laszlo
2016-06-01
Accelerated airway inflammation may play a crucial role in the pathophysiology of obstructive sleep apnoea (OSA); however this phenomenon has been investigated only in a limited number of studies. The analysis of exhaled breath represents a promising, non-invasive tool to evaluate airway inflammation in this context. The knowledge on exhaled biomarkers in OSA has been growing with an emerging number of methodological studies which help to interpret exhaled breath data. This article not only summarises the results of studies on exhaled breath condensate (EBC) biomarkers, exhaled volatile compounds and exhaled monoxides in OSA, but also aims to critically review methodological limitations and provide some guideline for further research. PMID:26426372
The Analysis of Quantitative Traits for Simple Genetic Models from Parental, F1 and Backcross Data
Elston, R. C.; Stewart, John
1973-01-01
The following models are considered for the genetic determination of quantitative traits: segregation at one locus, at two linked loci, at any number of equal and additive unlinked loci, and at one major locus and an indefinite number of equal and additive loci. In each case an appropriate likelihood is given for data on parental, F1 and backcross individuals, assuming that the environmental variation is normally distributed. Methods of testing and comparing the various models are presented, and methods are suggested for the simultaneous analysis of two or more traits. PMID:4711900
Comprehensive nanostructure and defect analysis using a simple 3D light-scatter sensor.
Herffurth, Tobias; Schröder, Sven; Trost, Marcus; Duparré, Angela; Tünnermann, Andreas
2013-05-10
Light scattering measurement and analysis is a powerful tool for the characterization of optical and nonoptical surfaces. A new 3D scatter measurement system based on a detector matrix is presented. A compact light-scatter sensor is used to characterize the scattering and nanostructures of surfaces and to identify the origins of anisotropic scattering features. The results from the scatter sensor are directly compared with white light interferometry to analyze surface defects as well as surface roughness and the corresponding scattering distributions. The scattering of surface defects is modeled based on the Kirchhoff integral equation and the approach of Beckmann for rough surfaces. PMID:23669841
NASA Technical Reports Server (NTRS)
Singleterry, Robert C., Jr.; Walker, Steven A.; Clowdsley, Martha S.
2016-01-01
The mathematical models for Solar Particle Event (SPE) high energy tails are constructed with several di erent algorithms. Since limited measured data exist above energies around 400 MeV, this paper arbitrarily de nes the high energy tail as any proton with an energy above 400 MeV. In order to better understand the importance of accurately modeling the high energy tail for SPE spectra, the contribution to astronaut whole body e ective dose equivalent of the high energy portions of three di erent SPE models has been evaluated. To ensure completeness of this analysis, simple and complex geometries were used. This analysis showed that the high energy tail of certain SPEs can be relevant to astronaut exposure and hence safety. Therefore, models of high energy tails for SPEs should be well analyzed and based on data if possible.
In Silico Genome Comparison and Distribution Analysis of Simple Sequences Repeats in Cassava
Vásquez, Andrea; López, Camilo
2014-01-01
We conducted a SSRs density analysis in different cassava genomic regions. The information obtained was useful to establish comparisons between cassava's SSRs genomic distribution and those of poplar, flax, and Jatropha. In general, cassava has a low SSR density (~50 SSRs/Mbp) and has a high proportion of pentanucleotides, (24,2 SSRs/Mbp). It was found that coding sequences have 15,5 SSRs/Mbp, introns have 82,3 SSRs/Mbp, 5′ UTRs have 196,1 SSRs/Mbp, and 3′ UTRs have 50,5 SSRs/Mbp. Through motif analysis of cassava's genome SSRs, the most abundant motif was AT/AT while in intron sequences and UTRs regions it was AG/CT. In addition, in coding sequences the motif AAG/CTT was also found to occur most frequently; in fact, it is the third most used codon in cassava. Sequences containing SSRs were classified according to their functional annotation of Gene Ontology categories. The identified SSRs here may be a valuable addition for genetic mapping and future studies in phylogenetic analyses and genomic evolution. PMID:25374887
Alkoshi, Salem; Maimaiti, Namaitijiang; Dahlui, Maznah
2014-01-01
Background Rotavirus infection is a major cause of childhood diarrhea in Libya. The objective of this study is to evaluate the cost-effectiveness of rotavirus vaccination in that country. Methods We used a published decision tree model that has been adapted to the Libyan situation to analyze a birth cohort of 160,000 children. The evaluation of diarrhea events in three public hospitals helped to estimate the rotavirus burden. The economic analysis was done from two perspectives: health care provider and societal. Univariate sensitivity analyses were conducted to assess uncertainty in some values of the variables selected. Results The three hospitals received 545 diarrhea patients aged≤5 with 311 (57%) rotavirus positive test results during a 9-month period. The societal cost for treatment of a case of rotavirus diarrhea was estimated at US$ 661/event. The incremental cost-effectiveness ratio with a vaccine price of US$ 27 per course was US$ 8,972 per quality-adjusted life year gained from the health care perspective. From a societal perspective, the analysis shows cost savings of around US$ 16 per child. Conclusion The model shows that rotavirus vaccination could be economically a very attractive intervention in Libya. PMID:25499622
Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds
Castro, Maria Eugenia; Percino, Maria Judith; Chapela, Victor M.; Ceron, Margarita; Soriano-Moro, Guillermo; Lopez-Cruz, Jorge; Melendez, Francisco J.
2013-01-01
A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)] pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and 1H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl-substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. 1H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and 1H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds. PMID:23429190
Simple model analysis on the negative-ion extraction from a plasma
Lishev, St.; Shivarova, A.; Tarnev, Kh.
2009-12-01
Extraction of negative hydrogen ions from a plasma is analyzed with a view to the description of the extraction region of the negative hydrogen ion-beam sources developed for additional heating of fusion plasmas. The numerical procedure introduced in the study is a modification of the indirect Poisson-Vlasov method. It uses a condition for the plasma meniscus and employs analogy with the particle-in-cell model simulation. The analysis of the results shows that the charged particle velocity distribution at the entrance of the extraction region influences the properties of the extracted beams and its effect should be considered when conditions for well converged beams are looked for through variation in the plasma density and in the potentials of the electrodes of the extraction system.
NASA Astrophysics Data System (ADS)
Zhang, Zhen-Hua; Song, Ren; Su, Yu-Mo; Lü, Gang; Zheng, Bo
2015-09-01
We perform a theoretical study on direct CP violation in in phase space around the intermediate states and . The possible interference between the amplitudes corresponding to the two resonances is taken into account, and the relative strong phase of the two amplitudes is treated as a free parameter. Our analysis shows that by a properly chosen strong phase, both the CP violation strength and the differential decay width accommodate the experimental results.
Infrared spectrum analysis of the dissociated states of simple amino acids
NASA Astrophysics Data System (ADS)
Sebben, Damien; Pendleton, Phillip
2014-11-01
In this work, we present detailed analyses of the dissociation of dilute aqueous solutions of glycine and of lysine over the range 1 < pH < 12. Using appropriate spectrum subtraction methods, we obtained ATR-IR spectra of the solvated species as a function of pH. Discernible changes in the ionic species were identified in the absorption region between 1800 and 1100 cm-1. By applying peak deconvolution techniques to the spectra, we correctly interpret the apparent peak shift from 1615 to 1600 cm-1 as being due to the receding NH3+ asymmetric deformation alongside the appearing COO- asymmetric stretching. The effect of aqueous solution environment was also investigated in terms of 10 and 100 mmol/L NaCl. Salt solution spectra at each pH were also subtracted from each solution phase spectrum. Analysis of the deconvoluted peak areas due to Cdbnd O and COO- at pH ranges < 4.5 and those due to NH2 and NH3+ for pH > 8 resulted in consistent pKa values for the amino acids.
A Simple Geotracer Compositional Correlation Analysis Reveals Oil Charge and Migration Pathways
Yang, Yunlai; Arouri, Khaled
2016-01-01
A novel approach, based on geotracer compositional correlation analysis is reported, which reveals the oil charge sequence and migration pathways for five oil fields in Saudi Arabia. The geotracers utilised are carbazoles, a family of neutral pyrrolic nitrogen compounds known to occur naturally in crude oils. The approach is based on the concept that closely related fields, with respect to filling sequence, will show a higher carbazole compositional correlation, than those fields that are less related. That is, carbazole compositional correlation coefficients can quantify the charge and filling relationships among different fields. Consequently, oil migration pathways can be defined based on the established filling relationships. The compositional correlation coefficients of isomers of C1 and C2 carbazoles, and benzo[a]carbazole for all different combination pairs of the five fields were found to vary extremely widely (0.28 to 0.94). A wide range of compositional correlation coefficients allows adequate differentiation of separate filling relationships. Based on the established filling relationships, three distinct migration pathways were inferred, with each apparently being charged from a different part of a common source kitchen. The recognition of these charge and migration pathways will greatly aid the search for new accumulations. PMID:26965479
A Simple Geotracer Compositional Correlation Analysis Reveals Oil Charge and Migration Pathways
NASA Astrophysics Data System (ADS)
Yang, Yunlai; Arouri, Khaled
2016-03-01
A novel approach, based on geotracer compositional correlation analysis is reported, which reveals the oil charge sequence and migration pathways for five oil fields in Saudi Arabia. The geotracers utilised are carbazoles, a family of neutral pyrrolic nitrogen compounds known to occur naturally in crude oils. The approach is based on the concept that closely related fields, with respect to filling sequence, will show a higher carbazole compositional correlation, than those fields that are less related. That is, carbazole compositional correlation coefficients can quantify the charge and filling relationships among different fields. Consequently, oil migration pathways can be defined based on the established filling relationships. The compositional correlation coefficients of isomers of C1 and C2 carbazoles, and benzo[a]carbazole for all different combination pairs of the five fields were found to vary extremely widely (0.28 to 0.94). A wide range of compositional correlation coefficients allows adequate differentiation of separate filling relationships. Based on the established filling relationships, three distinct migration pathways were inferred, with each apparently being charged from a different part of a common source kitchen. The recognition of these charge and migration pathways will greatly aid the search for new accumulations.
A Simple Geotracer Compositional Correlation Analysis Reveals Oil Charge and Migration Pathways.
Yang, Yunlai; Arouri, Khaled
2016-01-01
A novel approach, based on geotracer compositional correlation analysis is reported, which reveals the oil charge sequence and migration pathways for five oil fields in Saudi Arabia. The geotracers utilised are carbazoles, a family of neutral pyrrolic nitrogen compounds known to occur naturally in crude oils. The approach is based on the concept that closely related fields, with respect to filling sequence, will show a higher carbazole compositional correlation, than those fields that are less related. That is, carbazole compositional correlation coefficients can quantify the charge and filling relationships among different fields. Consequently, oil migration pathways can be defined based on the established filling relationships. The compositional correlation coefficients of isomers of C1 and C2 carbazoles, and benzo[a]carbazole for all different combination pairs of the five fields were found to vary extremely widely (0.28 to 0.94). A wide range of compositional correlation coefficients allows adequate differentiation of separate filling relationships. Based on the established filling relationships, three distinct migration pathways were inferred, with each apparently being charged from a different part of a common source kitchen. The recognition of these charge and migration pathways will greatly aid the search for new accumulations. PMID:26965479
Simple automatic strategy for background drift correction in chromatographic data analysis.
Fu, Hai-Yan; Li, He-Dong; Yu, Yong-Jie; Wang, Bing; Lu, Peng; Cui, Hua-Peng; Liu, Ping-Ping; She, Yuan-Bin
2016-06-01
Chromatographic background drift correction, which influences peak detection and time shift alignment results, is a critical stage in chromatographic data analysis. In this study, an automatic background drift correction methodology was developed. Local minimum values in a chromatogram were initially detected and organized as a new baseline vector. Iterative optimization was then employed to recognize outliers, which belong to the chromatographic peaks, in this vector, and update the outliers in the baseline until convergence. The optimized baseline vector was finally expanded into the original chromatogram, and linear interpolation was employed to estimate background drift in the chromatogram. The principle underlying the proposed method was confirmed using a complex gas chromatographic dataset. Finally, the proposed approach was applied to eliminate background drift in liquid chromatography quadrupole time-of-flight samples used in the metabolic study of Escherichia coli samples. The proposed method was comparable with three classical techniques: morphological weighted penalized least squares, moving window minimum value strategy and background drift correction by orthogonal subspace projection. The proposed method allows almost automatic implementation of background drift correction, which is convenient for practical use. PMID:27139215
Barin, Juliano Smanioto; Tischer, Bruna; Oliveira, Alessandra Stangherlin; Wagner, Roger; Costa, Adilson Ben; Flores, Erico Marlon Moraes
2015-12-15
In this work, the feasibility of infrared thermal imaging (ITI) is demonstrated to show its potential application in analytical chemistry. A system of ITI was combined with disposable microplates to perform enthalpimetric analysis, which was selected as an example in order to show the reliability of this method. In this way, the novel thermal infrared enthalpimetry (TIE) method was evaluated in neutralization, precipitation, redox, and complexation reactions, with a multichannel pipet for adding the reagent and an infrared camera to monitor the temperature of multiple reactions (up to 24 simultaneous reactions) in a contactless way. Analytical signals were obtained in only 10 s, and the difference in temperature (ΔT) before and after the reaction was used for the construction of calibration curves by use of reference solutions. More than 10,000 values were considered for the temperature determination for each reaction. The proposed method was applied for determination of the total acidity of vinegar as well as the chloride, iron, and calcium content of pharmaceuticals. The results were compared with those from conventional techniques (titration), and agreement between 96% and 101% was obtained. Sample throughput could even reach thousands of samples analyzed in 1 h. These preliminary results demonstrate the important features of TIE and possible application for other matrices and analytical parameters. The proposed TIE could be spread to cover other enthalpimetric techniques, different reactors (e.g., microfluidic and paper analytical devices), and portable devices, thus reaching other fields of chemistry. PMID:26562490
Influential and theoretical analysis of nano-defect in the stub resonator.
Xu, Hui; Li, Hongjian; Li, Boxun; He, Zhihui; Chen, Zhiquan; Zheng, Mingfei
2016-01-01
We investigate a classic optical effect based on plasmon induced transparency (PIT) in a metal-insulator-metal (MIM) bus waveguide coupled with a single defective cavity. With the coupled mode theory (CMT), a theoretical model, for the single defective cavity, is established to study spectral features in the plasmonic waveguide. We can achieve a required description for the phenomenon, and the theoretical results also agree well with the finite-difference time-domain (FDTD) method. Our researches show that the defect's position and size play important roles in the PIT phenomenon. By adjusting the position and size of the defect, we can realize the PIT phenomenon well and get the required slow light effect. The proposed model and findings may provide guidance for fundamental research of the control of light in highly integrated optical circuits. PMID:27477218
Analysis of theoretical and real values of heat consumption in units of the apartment building
NASA Astrophysics Data System (ADS)
Pavloková, Petra; Richter, Aleš; Janša, Jan
2016-06-01
This article is focused on heat consumption in the apartment building and the factors affecting it. The apartment building has three entrances and four over ground floors and one underground floor. In the entire apartment building there are 24 flats, which they are identical (kitchen, bedroom, living room and bathroom). In flats on radiators were installed the ratio heat meters according to Act 318/2012 Coll. by the Metrology Act. The ratio heat meters are used for fair billing of the heat costs for all owners. Continuous monitoring of the actual heat consumption in the flats were collected data of the real heat consumption. The theoretical values of heat consumption were counted in software ENERGIE. The apartment building is divided into24 flats and the calculation was made for each of them. The theoretical and real heat consumption was compared.
Theoretical analysis and simulation study on a coaxial vircator with enhanced modulation
NASA Astrophysics Data System (ADS)
Ou, J. J.; Shao, H.; Zhang, Y. C.; Xiong, X. Z.; Liao, C.
2015-10-01
> Based on large-signal theory, a one-dimensional theoretical model of a coaxial vircator is developed to give the microwave gain of the nonlinear beam-wave interaction, and the effect of injected current premodulation on the microwave gain is analysed theoretically. In addition, a coaxial vircator with improved dual-cavity modulation structure, which has the advantage of enhancing the effect of the modulation cavity on the injected electron beam by way of feedback microwaves, is presented. The simulation results are presented to test the validity of the proposed theory, and it can be seen that the system power efficiency can become further strengthened by adjusting the parameters of the microwave feedback channel until the feedback electric field is at the proper phase. Finally, through optimization, a structure capable of generating 7.05 GW average output power and 19.5 % power conversion efficiency at 2.95 GHz operating frequency is obtained.
Theoretical and experimental analysis of H2 binding in a prototype metal organic framework material
Kong, Dr. Lingzhu; Cooper, Valentino R; Nijem, Nour; Li, Kunhao; Li, Jing; Chabal, Yves J.; Langreth, David C.
2009-01-01
Hydrogen adsorption by the metal organic framework (MOF) structure Zn2(BDC)2(TED) is investigated using a combination of experimental and theoretical methods. By use of the nonempirical van der Waals density-functional (vdW-DF) approach, it is found that the locus of deepest H2 binding positions lies within two types of narrow channel. The energies of the most stable binding sites, as well as the number of such binding sites, are consistent with the values obtained from experimental adsorption isotherms and heat of adsorption data. Calculations of the shift of the H H stretch frequency when adsorbed in the MOF give a value of approximately −30 cm−1 at the strongest binding point in each of the two channels. Ambient temperature infrared absorption spectroscopy measurements give a hydrogen peak centered at 4120 cm−1, implying a shift consistent with the theoretical calculations.
Influential and theoretical analysis of nano-defect in the stub resonator
NASA Astrophysics Data System (ADS)
Xu, Hui; Li, Hongjian; Li, Boxun; He, Zhihui; Chen, Zhiquan; Zheng, Mingfei
2016-08-01
We investigate a classic optical effect based on plasmon induced transparency (PIT) in a metal-insulator-metal (MIM) bus waveguide coupled with a single defective cavity. With the coupled mode theory (CMT), a theoretical model, for the single defective cavity, is established to study spectral features in the plasmonic waveguide. We can achieve a required description for the phenomenon, and the theoretical results also agree well with the finite-difference time-domain (FDTD) method. Our researches show that the defect’s position and size play important roles in the PIT phenomenon. By adjusting the position and size of the defect, we can realize the PIT phenomenon well and get the required slow light effect. The proposed model and findings may provide guidance for fundamental research of the control of light in highly integrated optical circuits.
Influential and theoretical analysis of nano-defect in the stub resonator
Xu, Hui; Li, Hongjian; Li, Boxun; He, Zhihui; Chen, Zhiquan; Zheng, Mingfei
2016-01-01
We investigate a classic optical effect based on plasmon induced transparency (PIT) in a metal-insulator-metal (MIM) bus waveguide coupled with a single defective cavity. With the coupled mode theory (CMT), a theoretical model, for the single defective cavity, is established to study spectral features in the plasmonic waveguide. We can achieve a required description for the phenomenon, and the theoretical results also agree well with the finite-difference time-domain (FDTD) method. Our researches show that the defect’s position and size play important roles in the PIT phenomenon. By adjusting the position and size of the defect, we can realize the PIT phenomenon well and get the required slow light effect. The proposed model and findings may provide guidance for fundamental research of the control of light in highly integrated optical circuits. PMID:27477218
NASA Astrophysics Data System (ADS)
Morris, Ljiubov; Caruana, Daren J.; Williams, David E.
2002-04-01
A simple device is described, capable of measuring reliably and reproducibly low levels (0.1 ppbv with a total analysis time of approximately 40 min) of volatile organic compounds (VOCs) in urban air and in the headspace of groundwater. The VOCs were pre-concentrated onto a small bed of Tenax TA®, and subsequently released by temperature-programmed thermal desorption (TPD). TPD profiles were recorded by a solid-state sensor array. The success of the method was based on a well defined TPD peak shape if the absorbent bed was sufficiently thin, linearity and additivity of appropriately transformed sensor signals, the use of a very stable sensor array utilizing chromium-titanium oxide as the sensor material and devices with different electrode gaps and the use of dry air as the carrier gas. Successful analysis of groundwater headspace was achieved by diluting the sample stream 1:4 with dry air (which prevented saturation of the adsorbent surface by water) and by introducing a dry air purge of the bed at room temperature before desorption (which removed excess water from the bed and hence stabilized the sensor baseline before the desorption). Principal components analysis and spectral decomposition (SD) methods were used successfully for identification of VOCs and quantification in simple mixtures. The SD method expressed the measured desorption trace on the elements of the sensor array as the sum of a small number of sensor array spectra. The individual desorption traces for each characteristic sensor spectrum thus derived could be further resolved by a peak fitting procedure because the TPD trace had a well defined form, in which both peak temperature and peak width in TPD correlated with the boiling temperature of the VOCs, and peak width varied according to functional type: phenols>aliphatics>alkyl-substituted benzenes.
NASA Astrophysics Data System (ADS)
Avilés, Misael O.; Ebner, Armin D.; Chen, Haitao; Rosengart, Axel J.; Kaminski, Michael D.; Ritter, James A.
2005-05-01
The use of a ferromagnetic wire implant placed near an artery to assist the collection of magnetic drug carrier particles (MDCPs) using an external magnet is theoretically studied. Three magnetic drug targeting (MDT) systems are evaluated in terms of their MDCP collection efficiency (CE): a permanent magnet and wire is better than a permanent magnet alone, which is better than a homogeneous magnetic field and wire.
Polarimetric glucose sensing using the Brewster-reflection off the eye lens: theoretical analysis
NASA Astrophysics Data System (ADS)
Boeckle, Stefan; Rovati, Luigi; Ansari, Rafat R.
2002-05-01
An important task of in vivo polarimetric glucose sensing is to find an appropriate way to optically access the aqueous humor of the human eye. In this paper two different approaches are analyzed theoretically and applied to the eye model of Le Grand. First approach is the tangential path of Cote et al., and the second is a new scheme of this paper of applying Brewster reflection off the eye lens.
Error control in the GCF: An information-theoretic model for error analysis and coding
NASA Technical Reports Server (NTRS)
Adeyemi, O.
1974-01-01
The structure of data-transmission errors within the Ground Communications Facility is analyzed in order to provide error control (both forward error correction and feedback retransmission) for improved communication. Emphasis is placed on constructing a theoretical model of errors and obtaining from it all the relevant statistics for error control. No specific coding strategy is analyzed, but references to the significance of certain error pattern distributions, as predicted by the model, to error correction are made.
NASA Technical Reports Server (NTRS)
Bourret, E. D.; Favier, J. J.; Witt, A. F.
1982-01-01
Directional melting of binary systems, as encountered during seeding in melt growth, is analyzed for concurrent compositional changes at the crystal-melt interface. It is shown that steady state conditions cannot normally be reached during seeding and that the growth interface temperature at the initial stages of seeded growth is a function of backmelt conditions. The theoretical treatment is numerically applied to Hg1-xCdXTe and Ga-doped Ge.
NASA Astrophysics Data System (ADS)
Yoshida, Shuhei; Mori, Jun; Yamamoto, Manabu
2015-05-01
Many kinds of recording techniques have been proposed for holographic data storages (HDS). Multiplexing recording technique is a primary contributor to determining the recording density in HDS. The method that utilizes spherical reference waves is characterized by the ability to enable multiplexing recording only by displacing (shifting or rotating) the recording medium. In this study, we propose a theoretical diffraction model of peristrophic multiplexing with spherical reference wave for HDS.
A Theoretical Analysis of a New Polarimetric Optical Scheme for Glucose Sensing in the Human Eye
NASA Technical Reports Server (NTRS)
Rovati, Luigi L.; Boeckle, Stefan; Ansari, Rafat R.; Salzman, Jack A. (Technical Monitor)
2002-01-01
The challenging task of in vivo polarimetric glucose sensing is the identification and selection of a scheme to optically access the aqueous humor of the human eye. In this short communication an earlier approach of Cote et al. is theoretically compared with our new optical scheme. Simulations of the new scheme using the eye model of Navarro, suggest that the new optical geometry can overcome the limitations of the previous approach for in vivo measurements of glucose in a human eye.
Rural-urban migration, informal sector and development policies: a theoretical analysis.
Gupta, M R
1993-06-01
"A theoretical model of rural-urban migration has been developed with special reference to the informal sector. The wage rate and employment in the informal sector are determined endogenously. The paper shows the simultaneous existence of open unemployment and informal sector in the urban area in migration equilibrium. The effects of alternative subsidy policies on unemployment and welfare of the workers are studied." The model is intended primarily for use in analyzing trends and policies in developing countries. PMID:12344755
NASA Astrophysics Data System (ADS)
Vetter, Philip A.; Wang, Luojia; Wang, Da-Wei; Scully, Marlan O.
2016-02-01
Single photon emission from a collection of resonantly excited two-level atoms is an expanding field. Recent work has shown single photon superradiance from an extended ensemble yields enhanced directional spontaneous emission. This paper presents an operator which commutes with the observables {{R}}2,{R}z and breaks their degeneracy for the single photon states. Its eigenvectors are a unimodular basis for the single photon states. A simple scheme is given for writing out these states directly without iterative construction and without requiring recourse to Gram-Schmidt orthogonalization. A relatively simple scheme is proposed for experimental realization. In the final part of the paper the mathematical method is extended to generate cooperative states with smaller cooperativity number R.
Su, Yuliang; Ren, Long; Meng, Fankun; Xu, Chen; Wang, Wendong
2015-01-01
Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and propagation criteria for the theoretical model of fracture network propagation and its derivation. A reasonable solution of the theoretical model for a tight oil reservoir is obtained and verified by a numerical discrete method. Through theoretical calculation and computer programming, the variation rules of formation stress fields, hydraulic fracture propagation patterns (FPP) and branch fracture propagation angles and pressures are analyzed. The results show that during the process of fracture propagation, the initial orientation of the principal stress deflects, and the stress fields at the fracture tips change dramatically in the region surrounding the fracture. Whether the ideal fracture network can be produced depends on the geological conditions and on the engineering treatments. This study has both theoretical significance and practical application value by contributing to a better understanding of fracture network propagation mechanisms in unconventional oil/gas reservoirs and to the improvement of the science and design efficiency of reservoir fracturing. PMID:25966285
Su, Yuliang; Ren, Long; Meng, Fankun; Xu, Chen; Wang, Wendong
2015-01-01
Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and propagation criteria for the theoretical model of fracture network propagation and its derivation. A reasonable solution of the theoretical model for a tight oil reservoir is obtained and verified by a numerical discrete method. Through theoretical calculation and computer programming, the variation rules of formation stress fields, hydraulic fracture propagation patterns (FPP) and branch fracture propagation angles and pressures are analyzed. The results show that during the process of fracture propagation, the initial orientation of the principal stress deflects, and the stress fields at the fracture tips change dramatically in the region surrounding the fracture. Whether the ideal fracture network can be produced depends on the geological conditions and on the engineering treatments. This study has both theoretical significance and practical application value by contributing to a better understanding of fracture network propagation mechanisms in unconventional oil/gas reservoirs and to the improvement of the science and design efficiency of reservoir fracturing. PMID:25966285
NASA Astrophysics Data System (ADS)
Shinnaka, Shinji
This paper presents a new characteristics analysis of dynamic mathematical model for synchronous reluctance motor, which is recently attracting attentions in conjunction with the problem of rotor phase selection and estimation based on the extended BEMF (back electromotive force) for sensorless drive. This paper gives the following new characteristic results in a simple unified analytical manner. 1) Change between positive and negative salient pole phases requires basically no modification to the dynamic mathematical model in the general reference frame. 2) Selection of positive or negative salient pole phase as rotor phase is no more than a preference of designers. 3) There exists a very simple deriving method of two stator flux models for explicit expression of the extended BEMF. 4) At least, four circuit equations with the extended BEMF exist, which are equivalent to each other on the same reference frame. 5) There exists duality among the four circuit equations from viewpoints of rotor phase selection. 6) The duality reinforces the above-mentioned results 1) to 5). Main results of this paper correct or reinforce the results recently reported by others.
NASA Astrophysics Data System (ADS)
Lin, Yuzhang; Allouche, Genevieve G.; Huang, James; Ashok, Amit; Gong, Qian; Coccarelli, David; Stoian, Razvan-Ionut; Gehm, Michael E.
2016-05-01
In this work we present an information-theoretic framework for a systematic study of checkpoint x-ray systems using photoabsorption measurements. Conventional system performance analysis of threat detection systems confounds the effect of the system architecture choice with the performance of a threat detection algorithm. However, our system analysis approach enables a direct comparison of the fundamental performance limits of disparate hardware architectures, independent of the choice of a specific detection algorithm. We compare photoabsorptive measurements from different system architectures to understand the affect of system geometry (angular views) and spectral resolution on the fundamental limits of the system performance.
Experimental and theoretical performance analysis for a CMOS-based high resolution image detector
NASA Astrophysics Data System (ADS)
Jain, Amit; Bednarek, Daniel R.; Rudin, Stephen
2014-03-01
Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present stateof- the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 μm pixels and an active area of 12 cm x 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/μR and 0.55 μR in high sensitivity mode, while they were 9.87 DN/μR and 2.77 μR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors.
Experimental and theoretical analysis of an optical current sensor for high power systems
NASA Astrophysics Data System (ADS)
Brigida, A. C. S.; Nascimento, I. M.; Mendonça, S.; Costa, J. C. W. A.; Martinez, M. A. G.; Baptista, J. M.; Jorge, P. A. S.
2013-03-01
A magneto-optical sensor, using a dual quadrature polarimetric processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated the feasibility of interrogating such sensor via the optical ground wire (OPGW) link installed in standard high power grids. The polarimetric bulk optical current sensor also was theoretically studied, and the effects of different sources of error considering practical deployment were evaluated. In particular, the interference from external magnetic fields in a tree-phase system was analyzed.
Arevalo, E.; Becker, A.
2005-10-15
We study numerically and analytically the role of the combined effect of self-focusing, geometrical focusing, and the plasma defocusing in the formation of the fluorescence signal during the filamentation of a Ti:sapphire laser pulse in nitrogen molecular gas. Results of numerical simulations are used to estimate the number of excited ions in the focal volume, which is proportional to the fluorescence signal. We find good agreement between the theoretical results and the experimental data, showing that such data can be used to get further insight into the effective focal volume during filamentation of femtosecond laser pulses in transparent media.
The theoretical analysis of the Fog removal in the LNG Ambient Vaporizer
NASA Astrophysics Data System (ADS)
Lee, T.; Lee, D.; Jeong, H.; Chung, H.
2015-09-01
The fog removal process is one of the important process in LNG Ambient Vaporizer. In this study we carried out theoretical study of the fog removal process in LNG Ambient Vaporizer. The LNG Ambient Vaporizer in Incheon area was used in our study. The fog temperature and the required energy produced from air fan to remove fog in LNG Ambient Vaporizer were calculated using average temperature of Incheon area in 2012 by Psychometruc Chart method. As a result we can be remove fog in LNG Ambient Vaporizer using Enthalpy[kW] energy in summer season and Enthalpy[kW] in winter season respectively.
NASA Astrophysics Data System (ADS)
Asada, Masahiro; Suzuki, Safumi
2015-07-01
The resonant tunneling diode (RTD) is a candidate for a compact and coherent source in the terahertz frequency range. We show theoretically that the oscillation characteristics of RTDs are strongly affected by the external feedback of partially reflected output power. The oscillation frequency and output power largely change with a small amount of the reflected output power as a periodic function of the position of the reflection object. A change in the current-voltage curve, which can be used for the detection of the external feedback, also occurs.
Theoretical analysis of terahertz parametric oscillator using KTiOPO4 crystal
NASA Astrophysics Data System (ADS)
Li, Zhongyang; Bing, Pibin; Yuan, Sheng
2016-08-01
Terahertz parametric oscillator (TPO) using KTiOPO4 (KTP) crystal with a noncollinear phase-matching scheme is investigated. Frequency tuning characteristics of terahertz wave (THz-wave) by varying the phase-matching angle and pump wavelength are analyzed. The expression of the effective parametric gain length under the noncollinear phase matching condition is deduced. Parametric gain and absorption characteristics of THz-wave in KTP are theoretically simulated for the first time. The characteristics of KTP for TPO are compared with MgO:LiNbO3. The analyses indicate that KTP is more suitable than MgO:LiNbO3 for TPO.
Information-theoretical analysis of topological entanglement entropy and multipartite correlations
NASA Astrophysics Data System (ADS)
Kato, Kohtaro; Furrer, Fabian; Murao, Mio
2016-02-01
A special feature of the ground state in a topologically ordered phase is the existence of large-scale correlations depending only on the topology of the regions. These correlations can be detected by the topological entanglement entropy or by a measure called irreducible correlation. We show that these two measures coincide for states obeying an area law and having zero correlation length. Moreover, we provide an operational meaning for these measures by proving its equivalence to the optimal rate of a particular class of secret sharing protocols. This establishes an information-theoretical approach to multipartite correlations in topologically ordered systems.
The relationship between theoretical memory psychology and art of memory: a historical analysis.
Holzapfel, Wolfgang
2005-01-01
The split between the theoretical branch and the practice--oriented art of memory psychology has existed for centuries. Whereas the theory of memory involved creation of elaborate models to elucidate the structure and processes of memory, in contrast the art of memory embraced techniques to enhance memory performance. One might expect a close relationship between practice and theory. This is, however, not the case. Theorists and memory artists criticized, fought, or ignored each other, as is demonstrated by examples from the 16th to the 19th century. PMID:19244672
Theoretic analysis of liquid film movement and its disintegration near the orifice of atomizer
NASA Astrophysics Data System (ADS)
Zhou, Meng; Zhuang, Fengchen
1993-04-01
The movement of a conic liquid film in a restricted space is studied in this paper. The film is produced by a centrifugal nozzle and impinged on by a high-speed gas stream. Based on the theory of aerodynamics, some theoretical formulas for liquid film movement are established, a criterion of breaking up the moving liquid film is proposed and a formula for calculating the size of droplet formed by disintegration of the liquid film is presented. The calculation results can be used as a reference for atomizer design.
Experimental Evidence and Theoretical Analysis of Nanobubble Stability Within Graphene Nanoscrolls.
Mokkapati, V R S S; Ozguz, Volkan; Kosar, Ali
2016-06-01
In this study direct observation and dynamics of nanoscale water and nanobubbles within graphene nanoscrolls were reported. The life time of these nanobubbles is much higher than expected, which we propose is due to the combination of several factors including localized heating and surface charge. The stability of the nanobubbles within graphene nanoscrolls has been theoretically analyzed. The nanobubbles inside these nanoscrolls reveal a wide distribution of graphene-water contact angles. Bubble dynamics within these graphene nanochannels was directly observed and recorded. PMID:27427730
NASA Technical Reports Server (NTRS)
Beatty, T. D.
1975-01-01
A theoretical method is presented for the computation of the flow field about an axisymmetric body operating in a viscous, incompressible fluid. A potential flow method was used to determine the inviscid flow field and to yield the boundary conditions for the boundary layer solutions. Boundary layer effects in the forces of displacement thickness and empirically modeled separation streamlines are accounted for in subsequent potential flow solutions. This procedure is repeated until the solutions converge. An empirical method was used to determine base drag allowing configuration drag to be computed.
Polarimetric Glucose Sensing Using Brewster Reflection off of Eye Lens: Theoretical Analysis
NASA Technical Reports Server (NTRS)
Boeckle, Stefan; Rovati, Luigi; Ansari, Rafat R.
2002-01-01
An important task of in vivo polarimetric glucose sensing is to find an appropriate way to optically access the aqueous humor of the human eye. In this paper two different approaches are analyzed theoretically and applied to the eye model of Le Grand. First approach is the tangential path of Cote, et al. (G.L. Cot6, M.D. Fox, and R.B. Northrop: Noninvasive Optical Polarimetric Glucose Sensing Using a True Phase Measurement Technique. IEEE Transactions on Biomedical Engineering, vol. 39, no. 7, pp. 752-756, 1992.) and the second is a new scheme of this paper of applying Brewster reflection off the eye lens.
Seismic analysis of the solar interior. I - Can opacity changes improve the theoretical frequencies?
NASA Technical Reports Server (NTRS)
Korzennik, Sylvain G.; Ulrich, Roger K.
1989-01-01
The paper describes the application of seismic inverse theory to the deduction of properties of the solar interior using presently available measured frequencies of the solar oscillations. Only the solar opacity is included in this application. This study has used the spectral expansion method of Lanczos and Jackson to derive changes to the opacity which improve agreement between the theoretical and observed frequencies of oscillation. It is found that a family of opacity changes exists which yields models that improve the frequency agreement by amounts that are indistinguishable among the family members.
NASA Astrophysics Data System (ADS)
Pan, B.; Wang, B.; Lubineau, G.
2016-07-01
Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work.
Theoretical analysis of spectral lines of one- and two-electron ions in hot plasmas
Rozsnyai, B.F.; Einwohner, T.
1982-07-28
We discuss the line shapes for the 1s-2p, 1s-3p and (ls)/sup 2/ - 1s2p, (1s)/sup 2/ - 1s3p absorption lines in hot plasmas. In our model calculations the perturbing ions are considered quasi-static and widths due to collisions with electrons are calculated in the impact approximation. The collective effect of the plasma electrons is accounted for by a self-consistent model or by a simple Debye-Hueckel screening. These models in general predict different line shapes. We present calculations for the HeII, SiXIV and SiXIII ions.
NASA Astrophysics Data System (ADS)
Pekkan, E.; Tun, M.; Guney, Y.; Mutlu, S.
2015-06-01
A large part of the residential areas in Turkey are at risk from earthquakes. The main factors that threaten residential areas during an earthquake are poor quality building stock and soil problems. Liquefaction, loss of bearing capacity, amplification, slope failure, and landslide hazards must be taken into account for residential areas that are close to fault zones and covered with younger sediments. Analyzing these hazards separately and then combining the analyses would ensure a more realistic risk evaluation according to population density than analyzing several risks based on a single parameter. In this study, an integrated seismic risk analysis of central Eskişehir was performed based on two earthquake related parameters, liquefaction and amplification. The analysis used a simple weighting method. Other earthquake-related problems such as loss of bearing capacity, landslides, and slope failures are not significant for Eskişehir because of the geological and the topographical conditions of the region. According to the integrated seismic risk analysis of the Eskişehir residential area, the populated area is found to be generally at medium to high risk during a potential earthquake.
NASA Astrophysics Data System (ADS)
Guadarrama, Patricia; Terán, Gerardo; Ramos, Estrella; Gutiérrez, Jorge; Hernández, Madelyn
2015-04-01
The synthesis of novel highly delocalized push-pull dendrons is described. A modified protocol to conventional Csbnd C coupling reaction was used with moderate yields. The excited state dipole moments of synthesized dendrons were estimated by the solvatochromic model using the ETN polarity scale. In case of dendron of second generation with donor-acceptor groups, values around 23 D are obtained, denoting an efficient charge separation crucial in photovoltaic processes. From the theoretical analysis, there is a clear evidence of highly efficient electron delocalization in case of push-pull dendrons. The chosen theoretical model (M05-2X/cc-pVDZ) to describe the electronic behavior of the molecules under study was very precise in the estimation of dipole moments in excited state, with differences of 0.5-2.2 D, compared with the values obtained by the solvatochromic model.
NASA Astrophysics Data System (ADS)
Tsumuraya, Takao; Shishidou, Tatsuya; Oguchi, Tamio
2008-06-01
We present a theoretical analysis and interpretation of the x-ray absorption near-edge structure of x-ray absorption spectroscopy (XAS) at the titanium K -edge of several Ti compounds for understanding catalysis mechanism in lithium amide LiNH2 and imide Li2NH systems for hydrogen storage. Our theoretical approach is based on first-principles calculations using all-electron full-potential linear augmented plane-wave method. Chemical bonding and local geometry of catalytically-active Ti states in the hydrogen desorption reaction LiNH2+LiH→Li2NH+H2 are investigated. It is found that XAS spectra of some compounds consisting of elements Li, N, H, and Ti are quite similar to measured ones of catalytically-active Ti compounds. We conclude that Ti ions may occupy the Li sites in LiNH2 during the reaction.
NASA Technical Reports Server (NTRS)
Williams, M.; Harris, W. L.
1984-01-01
The purpose of the analysis is to determine if inflow turbulence distortion may be a cause of experimentally observed changes in sound pressure levels when the rotor mean loading is varied. The effect of helicopter rotor mean aerodynamics on inflow turbulence is studied within the framework of the turbulence rapid distortion theory developed by Pearson (1959) and Deissler (1961). The distorted inflow turbulence is related to the resultant noise by conventional broadband noise theory. A comparison of the distortion model with experimental data shows that the theoretical model is unable to totally explain observed increases in model rotor sound pressures with increased rotor mean thrust. Comparison of full scale rotor data with the theoretical model shows that a shear-type distortion may explain decreasing sound pressure levels with increasing thrust.
A theoretical analysis of the reaction between ethyl and molecular oxygen
James A. Miller; Stephen J. Klippenstein; Stuart H. Robertson
2000-12-13
Using a combination of electronic-structure theory, variational transition-state theory, and solutions to the time-dependent master equation, the authors have studied the kinetics of the title reaction theoretically over wide ranges of temperature and pressure. The agreement between theory and experiment is quite good. By comparing the theoretical and experimental results describing the kinetic behavior, they have been able to deduce a value for the C{sub 2}H{sub 5}-O{sub 2} bond energy of {approximately}34 kcal/mole and a value for the exit-channel transition-state energy of {minus}4.3 kcal/mole (measured from reactants). These numbers compare favorably with the electronic-structure theory predictions of 33.9 kcal/mole and {minus}3.0 kcal/mole, respectively. The master-equation solutions show three distinct temperature regimes for the reaction, discussed extensively in the paper. Above T {approx} 700 K, the reaction can be written as an elementary step, C{sub 2}H{sub 5} + O{sub 2} {leftrightarrow} C{sub 2}H{sub 4} + HO{sub 2}, with the rate coefficient, k(T) = 3.19 x 10{sup {minus}17} T{sup 1.02} exp(2035/RT) cm{sup 3}/molec.-sec., independent of pressure even though the intermediate collision complex may suffer a large number of collisions.
Theoretical analysis of dynamic chemical imaging with lasers using high-order harmonic generation
Van-Hoang Le; Anh-Thu Le; Xie Ruihua; Lin, C. D.
2007-07-15
We report theoretical investigations of the tomographic procedure suggested by Itatani et al. [Nature (London) 432, 867 (2004)] for reconstructing highest occupied molecular orbitals (HOMOs) using high-order harmonic generation (HHG). Due to the limited range of harmonics from the plateau region, we found that even under the most favorable assumptions, it is still very difficult to obtain accurate HOMO wave functions using the tomographic procedure, but the symmetry of the HOMOs and the internuclear separation between the atoms can be accurately extracted, especially when lasers of longer wavelengths are used to generate the HHG. Since the tomographic procedure relies on approximating the continuum wave functions in the recombination process by plane waves, the method can no longer be applied upon the improvement of the theory. For future chemical imaging with lasers, we suggest that one may want to focus on how to extract the positions of atoms in molecules instead, by developing an iterative method such that the theoretically calculated macroscopic HHG spectra can best fit the experimental HHG data.
Experimental and theoretical analysis of tubular membrane aeration for Mammalian cell bioreactors.
Qi, Hanshi N; Goudar, Chetan T; Michaels, James D; Henzler, Hans-Jugen; Jovanovic, Goran N; Konstantinov, Konstantin B
2003-01-01
A combination of experimental and theoretical approaches was used to characterize the dynamics of oxygen transfer in a membrane-aerated bioreactor. Pressure profiles along the length of the membrane at varying entrance and exit pressures were determined by actual experimental measurements, unlike most previous studies that have relied solely on theoretical descriptions of the pressure profile in the tubing. The mass transfer coefficient, k(L)a, was also determined under these conditions and was found to be essentially independent of tubing exit pressure. Measurement of the tubing pressure profile coupled with estimation of k(L)a allowed for computation of the oxygen transfer rate (OTR) along the length of the tubing. A mathematical model that incorporated friction pressure loss and losses due to tubing bending was developed to describe the pressure and hence OTR characteristics of membrane-aerated systems. The applicability of the model was verified by testing it on experimentally measured pressure data, and in all cases the model accurately described experimental data. When tubing properties are known, the mathematical model presented in this study allows for a priori estimation of OTR profiles along the length of the tubing. This information is vital for optimal design and scale-up of membrane-aerated bioreactors for mammalian cell culture. PMID:12892480
Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures
NASA Astrophysics Data System (ADS)
Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi
Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.
Thelen, Brian J; Valenzuela, John R; LeBlanc, Joel W
2016-04-01
This paper deals with super-resolution (SR) processing and associated theoretical performance assessment for under-sampled video data collected from a moving imaging platform with unknown motion and assuming a relatively flat scene. This general scenario requires joint estimation of the high-resolution image and the parameters that determine a projective transform that relates the collected frames to one another. A quantitative assessment of the variance in the random error as achieved through a joint-estimation approach (e.g., SR image reconstruction and motion estimation) is carried out via the general framework of M-estimators and asymptotic statistics. This approach provides a performance measure on estimating the fine-resolution scene when there is a lack of perspective information and represents a significant advancement over previous work that considered only the more specific scenario of mis-registration. A succinct overview of the theoretical framework is presented along with some specific results on the approximate random error for the case of unknown translation and affine motions. A comparison is given between the approximated random error and that actually achieved by an M-estimator approach to the joint-estimation problem. These results provide insight on the reduction in SR reconstruction accuracy when jointly estimating unknown inter-frame affine motion. PMID:27140759
Theoretical analysis of a rotating-disk partially confocal scanning microscope.
Conchello, J A; Lichtman, J W
1994-02-01
Confocal scanning microscopy is widely used for three-dimensional (3-D) visualization of fixed specimens but has found only a limited 3-D reconstruction application for living specimens because the high intensity of the excitation often damages the specimen or causes the fluorescent dye to bleach. Computational optical-sectioning microscopy also suffers from drawbacks because nonconfocal 3-D imaging is fundamentally constrained by an artifactual elongation in the optical axis imposed by the so-called missing cone. We investigate the imaging properties of a new rotating-disk partially confocal scanning microscope (PCSM) that greatly reduces collection time by using multiple apertures for both excitation and detection, effectively working as many confocal microscopes in parallel. We show that this PCSM behaves as a hybrid microscope; near the in-focus plane it behaves near the theoretical optimum for confocal microscopy, and away from this plane its behavior approaches that of a nonconfocal microscope. We also show that the rotating-disk PCSM does not suffer from a missing cone. In fact, the optical transfer function of the theoretically optimal confocal microscope and the rotating-disk PCSM have practically the same bandpass in the spatial-frequency domain. PMID:20862053
Sigeti, David E.; Pelak, Robert A.
2012-09-11
We present a Bayesian statistical methodology for identifying improvement in predictive simulations, including an analysis of the number of (presumably expensive) simulations that will need to be made in order to establish with a given level of confidence that an improvement has been observed. Our analysis assumes the ability to predict (or postdict) the same experiments with legacy and new simulation codes and uses a simple binomial model for the probability, {theta}, that, in an experiment chosen at random, the new code will provide a better prediction than the old. This model makes it possible to do statistical analysis with an absolute minimum of assumptions about the statistics of the quantities involved, at the price of discarding some potentially important information in the data. In particular, the analysis depends only on whether or not the new code predicts better than the old in any given experiment, and not on the magnitude of the improvement. We show how the posterior distribution for {theta} may be used, in a kind of Bayesian hypothesis testing, both to decide if an improvement has been observed and to quantify our confidence in that decision. We quantify the predictive probability that should be assigned, prior to taking any data, to the possibility of achieving a given level of confidence, as a function of sample size. We show how this predictive probability depends on the true value of {theta} and, in particular, how there will always be a region around {theta} = 1/2 where it is highly improbable that we will be able to identify an improvement in predictive capability, although the width of this region will shrink to zero as the sample size goes to infinity. We show how the posterior standard deviation may be used, as a kind of 'plan B metric' in the case that the analysis shows that {theta} is close to 1/2 and argue that such a plan B should generally be part of hypothesis testing. All the analysis presented in the paper is done with a general
Graph Theoretical Analysis Reveals: Women's Brains Are Better Connected than Men's.
Szalkai, Balázs; Varga, Bálint; Grolmusz, Vince
2015-01-01
Deep graph-theoretic ideas in the context with the graph of the World Wide Web led to the definition of Google's PageRank and the subsequent rise of the most popular search engine to date. Brain graphs, or connectomes, are being widely explored today. We believe that non-trivial graph theoretic concepts, similarly as it happened in the case of the World Wide Web, will lead to discoveries enlightening the structural and also the functional details of the animal and human brains. When scientists examine large networks of tens or hundreds of millions of vertices, only fast algorithms can be applied because of the size constraints. In the case of diffusion MRI-based structural human brain imaging, the effective vertex number of the connectomes, or brain graphs derived from the data is on the scale of several hundred today. That size facilitates applying strict mathematical graph algorithms even for some hard-to-compute (or NP-hard) quantities like vertex cover or balanced minimum cut. In the present work we have examined brain graphs, computed from the data of the Human Connectome Project, recorded from male and female subjects between ages 22 and 35. Significant differences were found between the male and female structural brain graphs: we show that the average female connectome has more edges, is a better expander graph, has larger minimal bisection width, and has more spanning trees than the average male connectome. Since the average female brain weighs less than the brain of males, these properties show that the female brain has better graph theoretical properties, in a sense, than the brain of males. It is known that the female brain has a smaller gray matter/white matter ratio than males, that is, a larger white matter/gray matter ratio than the brain of males; this observation is in line with our findings concerning the number of edges, since the white matter consists of myelinated axons, which, in turn, roughly correspond to the connections in the brain graph
NASA Astrophysics Data System (ADS)
Garel, Fanny; Kaminski, Edouard; Tait, Stephen; Limare, Angela
2010-05-01
Management of effusive volcanic crises has to be based on the quantitative interpretation of flow monitoring. An important issue is the ability to predict where the flow will go, and when it will stop. Geophysical fluid dynamics shows that the spreading of lava flows is mainly controlled by its rheology and the eruptive mass flux. Hence the key question is how to evaluate them during the eruption (rather than afterwards). A relationship between the surface structure temperature and the eruption rate is likely to exist, based on the first-order argument that higher eruption rates should correspond to larger energy radiated by a lava flow. A theoretical formula combining some empirical parameters was developed by Harris and co-workers (review in Harris et al., 2007) and is used to estimate lava flow rate from satellite. However, the theoretical grounds of this technique, as well as its domain of validity, remain questioned. Here we propose a systematic theoretical study to help to define the validity domain of this approach and to investigate whether or not it can be refined and/or modify to better assess flow rates. We chose in our approach to study at lab-scale a flow with a rheology simpler than that of the natural lava, but taking into account all the complexity of the cooling process at the surface of the flow, by radiation and convection. We used fully controlled experimental parameters, especially the cooling conditions, the flux rate and geometry of the flow. The spreading geometry is the one of an axisymmetric viscous gravity current of newtonian viscosity (Huppert, 1982). For a given enthalpy content, the coupled cooling/spreading processes are characterized by two dimensionless numbers. A first one quantifies the efficiency of the surface cooling compared to the heat advected in the flow. The second one quantifies the relative efficiency of radiative and convective surface cooling. We identify different stages of cooling as a function of these numbers and
Graph Theoretical Analysis Reveals: Women’s Brains Are Better Connected than Men’s
Szalkai, Balázs; Varga, Bálint; Grolmusz, Vince
2015-01-01
Deep graph-theoretic ideas in the context with the graph of the World Wide Web led to the definition of Google’s PageRank and the subsequent rise of the most popular search engine to date. Brain graphs, or connectomes, are being widely explored today. We believe that non-trivial graph theoretic concepts, similarly as it happened in the case of the World Wide Web, will lead to discoveries enlightening the structural and also the functional details of the animal and human brains. When scientists examine large networks of tens or hundreds of millions of vertices, only fast algorithms can be applied because of the size constraints. In the case of diffusion MRI-based structural human brain imaging, the effective vertex number of the connectomes, or brain graphs derived from the data is on the scale of several hundred today. That size facilitates applying strict mathematical graph algorithms even for some hard-to-compute (or NP-hard) quantities like vertex cover or balanced minimum cut. In the present work we have examined brain graphs, computed from the data of the Human Connectome Project, recorded from male and female subjects between ages 22 and 35. Significant differences were found between the male and female structural brain graphs: we show that the average female connectome has more edges, is a better expander graph, has larger minimal bisection width, and has more spanning trees than the average male connectome. Since the average female brain weighs less than the brain of males, these properties show that the female brain has better graph theoretical properties, in a sense, than the brain of males. It is known that the female brain has a smaller gray matter/white matter ratio than males, that is, a larger white matter/gray matter ratio than the brain of males; this observation is in line with our findings concerning the number of edges, since the white matter consists of myelinated axons, which, in turn, roughly correspond to the connections in the brain graph
A Theoretical and Experimental Analysis of SBS Suppression Through Modification of Amplifier Seed
NASA Astrophysics Data System (ADS)
Zeringue, Clint Matthew
2011-12-01
Theoretical and experimental investigations of stimulated Brillouin scattering (SBS) are conducted in Yb-doped fiber amplifiers when the amplifier is simultaneously seeded with multiple distinct frequencies or with a phase modulated signal. To this end, detailed models of the SBS process are developed consisting of both a steady-state approach described mathematically by a coupled set of ordinary differential equations and also transient effects described by a coupled set of partial differential equations. For the multi-frequency seeded case, the equations are solved in the steady-state limit and include the effects of four-wave mixing (FWM), intrinsic and external thermal gradients, and laser gain. In one configuration of the multi-seeded case, the signals are separated at twice the acoustic frequency of the fiber medium in order to create nonlinear Brillouin gain coupling between the seeds and Stokes signals, which suppresses the SBS process in the highest frequency seed. The concept is theoretically investigated for the two and three seeded cases. It is shown that for this scheme, FWM becomes quite significant making this concept unlikely in a practical application requiring single-frequency output. Alternatively, a novel concept is developed to suppress SBS in fiber amplifiers that relies on laser gain competition among multiple seeds to create both a favorable thermal gradient and a reduced effective length for the SBS process. In one configuration, the amplifier is simultaneously seeded with a broadband (Deltalambda˜ 0.1nm) and single-frequency Delta v ˜100kHz seed. In this case, several experiments are performed to validate the theoretical predictions with experiments leading to a 203 W polarization maintaining (PM), co-pumped monolithic fiber amplifier demonstration. To the best of our knowledge, this output power is the highest reported in the literature to date for such an amplifier. A time-dependent model of the SBS process initiated from random
Theoretical analysis of solar-driven natural convection energy conversion systems
Jacobs, E.W.; Lasier, D.D.
1984-01-01
This report presents a theoretical study of solar-powered natural convection tower (chimney) performance. Both heated and cooled towers are analyzed; the latter uses evaporating water as the cooling mechanism. The results, which are applicable to any open-cycle configuration, show that the ideal conversion efficiencies of both heated and cooled natural convection towers are linear functions of height. The performance of a heated tower in an adiabatic atmosphere ideally approaches the Carnot efficiency limit of approx. = 3.4%/km (1.0%/1000 ft). Including water pumping requirements, the ideal limit to cooled tower performance is approx. = 2.75%/km (0.85%/1000 ft). Ambient atmospheric conditions such as vertical temperature gradient (lapse rate) and relative humidity can have significantly adverse effects on natural convection tower performance. The combined effects of lapse rate and ambient relative humidity are especially important to cooled natural convection towers.
Tenforde, T.S.; Gaffey, C.T.; Moyer, B.R.; Budinger, T.F.
1983-01-01
Simultaneous measurements were made of the electrocardiogram (ECG) and the intraarterial blood pressure of adult male Macaca monkeys during acute exposure to homogeneous stationary magnetic fields ranging in strength up to 1.5 tesla. An instantaneous, field strength-dependent increase in the ECG signal amplitude at the locus of the T wave was observed in fields greater than 0.1 tesla. The temporal sequence of this signal in the ECG record and its reversibility following termination of the magnetic field exposure are consistent with an earlier suggestion that it arises from a magnetically induced aortic blood flow potential superimposed on the native T-wave signal. No measurable alterations in blood pressure resulted from exposure to fields up to 1.5 tesla. This experimental finding is in agreement with theoretical calculations of the magnetohydrodynamic effect on blood flow in the major arteries of the cardiovascular system. 27 references, 1 figure, 1 table.
NASA Technical Reports Server (NTRS)
Stinespring, C. D.; Spear, K. E.
1985-01-01
A combined experimental and theoretical study to characterize the effects of gravitationally-induced transport on atmospheric pressure silicon epitaxy by SiH4 pyrolysis is planned. Experimentally, flow regimes in which free convective transport contributes to the Chemical Vapor Deposition (CVD) process will be identified, and, for these conditions, the flow and deposition process will be characterized. Specifically, this will include measurements of three dimensional temperature variations using in situ Rayleigh scattering, gas phase composition profiles using laser absorption and fluorescence techniques, and deposition rates and defect densities. Subsequently, the free convective transport contribution to the CVD process will be minimized and/or altered while leaving deposition chemistry unaltered, and the characterization will be repeated. Based on these analyses, the effects of gravitationally-induced transport on atmospheric pressure CVD will be assessed.
Theoretical analysis and design of a near-infrared broadband absorber based on EC model.
Zhang, Qing; Bai, Lihua; Bai, Zhengyuan; Hu, Pidong; Liu, Chengpu
2015-04-01
We theoretically introduced a design paradigm and tool by extending the circuit functionalities from radio frequency to near infrared domain, and its first usage to design a broadband near-infrared (1.5μm~3.5μm) absorber, is successfully demonstrated. After extracting the equivalent circuit (EC) model of the absorber structure, the formerly relatively complicated frequency response can be evaluated relatively easily based on classic circuit formulas. The feasibility is confirmed by its consistency with the rigorous FDTD calculation. The absorber is an array of truncated metal-dielectric multilayer composited pyramid unit structure, and the gradually modified square patch design makes the absorber be not sensitive to the incident angle and polarization of light. PMID:25968728
Research and theoretical analysis of new fiber Bragg grating sensor demodulation system
NASA Astrophysics Data System (ADS)
Li, Yaocheng; Wang, Hai-tong; Wang, Ping
2015-02-01
In order to measure high-precision and large scale sensing signal and solve two-values question in signal detecting of strain sensor, we design a new kind of FBG matching demodulation system based on fiber Bragg grating matching demodulation principle. Through paralleling connection two groups of grating-matching whose center wavelength equal to sensing grating's, and then analyzing reflectance spectrum, we could get the relationship of strain and optical power detected by photoelectric detector. Then we can set up the theoretical model and complete system simulation. The simulation results show that the scheme is feasible. The scheme not only can solve the problem of double values and can simultaneously detect the positive and negative strain. The sensor measurement range can be up to952ue.
Theoretical analysis of the focusing of acoustic waves by two-dimensional sonic crystals
NASA Astrophysics Data System (ADS)
Gupta, Bikash C.; Ye, Zhen
2003-03-01
Motivated by a recent experiment on acoustic lenses, we perform numerical calculations based on a multiple scattering technique to investigate the focusing of acoustic waves with sonic crystals formed by rigid cylinders in air. The focusing effects for crystals of various shapes are examined. The dependence of the focusing length on the filling factor is also studied. It is observed that both the shape and filling factor play a crucial role in controlling the focusing. Furthermore, the robustness of the focusing against disorders is studied. The results show that the sensitivity of the focusing behavior depends on the strength of positional disorders. The theoretical results compare favorably with the experimental observations, reported by Cervera, et al. [Phys. Rev. Lett. 88, 023902 (2002)].
Quantum-field-theoretic analysis of inflation dynamics in a (2+1)-dimensional universe
Samiullah, M. ); Eboli, O. ); Pi, S. )
1991-10-15
We reexamine inflationary scenarios based on slow-rollover transitions, which occur under various initial conditions of the inflation-driving scalar field. We examine inflation dynamics using a recently developed calculational technique for studying a quantum-field-theoretic system in an external environment that is itself changing with time. This method, based on the functional Schroedinger picture, uses a self-consistent Gaussian approximation that, unlike ordinary perturbation theory, reflects some of the nonlinearities of the full quantum theory. Our treatment is confined to planar universes, where the approximation techniques do not suffer from well-known problems associated with scalar field self-interactions in four-dimensional space-time. However, for these toy models we can present concrete and explicit results.
NASA Technical Reports Server (NTRS)
Katz, Daniel S.; Cwik, Tom; Fu, Chuigang; Imbriale, William A.; Jamnejad, Vahraz; Springer, Paul L.; Borgioli, Andrea
2000-01-01
The process of designing and analyzing a multiple-reflector system has traditionally been time-intensive, requiring large amounts of both computational and human time. At many frequencies, a discrete approximation of the radiation integral may be used to model the system. The code which implements this physical optics (PO) algorithm was developed at the Jet Propulsion Laboratory. It analyzes systems of antennas in pairs, and for each pair, the analysis can be computationally time-consuming. Additionally, the antennas must be described using a local coordinate system for each antenna, which makes it difficult to integrate the design into a multi-disciplinary framework in which there is traditionally one global coordinate system, even before considering deforming the antenna as prescribed by external structural and/or thermal factors. Finally, setting up the code to correctly analyze all the antenna pairs in the system can take a fair amount of time, and introduces possible human error. The use of parallel computing to reduce the computational time required for the analysis of a given pair of antennas has been previously discussed. This paper focuses on the other problems mentioned above. It will present a methodology and examples of use of an automated tool that performs the analysis of a complete multiple-reflector system in an integrated multi-disciplinary environment (including CAD modeling, and structural and thermal analysis) at the click of a button. This tool, named MOD Tool (Millimeter-wave Optics Design Tool), has been designed and implemented as a distributed tool, with a client that runs almost identically on Unix, Mac, and Windows platforms, and a server that runs primarily on a Unix workstation and can interact with parallel supercomputers with simple instruction from the user interacting with the client.
Theoretical and experimental analysis of injection seeding a Q-switched alexandrite laser
NASA Technical Reports Server (NTRS)
Prasad, C. R.; Lee, H. S.; Glesne, T. R.; Monosmith, B.; Schwemmer, G. K.
1991-01-01
Injection seeding is a method for achieving linewidths of less than 500 MHz in the output of broadband, tunable, solid state lasers. Dye lasers, CW and pulsed diode lasers, and other solid state lasers have been used as injection seeders. By optimizing the fundamental laser parameters of pump energy, Q-switched pulse build-up time, injection seed power and mode matching, one can achieve significant improvements in the spectral purity of the Q-switched output. These parameters are incorporated into a simple model for analyzing spectral purity and pulse build-up processes in a Q-switched, injection-seeded laser. Experiments to optimize the relevant parameters of an alexandrite laser show good agreement.
Theoretical Analysis of Carbon-Nanotube-Based Mixers and Frequency Multipliers
NASA Astrophysics Data System (ADS)
Abuelma'Atti, Muhammad Taher
2010-05-01
In this paper closed-form expressions are presented for the current components in a CNT-based p-n junction diode resulting from a multisinusoidal input voltage. The expressions obtained, in terms of the modified Bessel functions, are simple and can be used for calculating the amplitudes of the fundamental, harmonics and intermodulation (mixing) current components in the CNT-based p-n junction diode. Using these expressions the performance of the CNT-based p-n junction diode excited by an equal-amplitude two-tone was studied in detail. The results obtained show that the amplitudes of the harmonic and mixing components are strongly dependent on the DC bias voltage, the series resistance and the ideality factor of the p-n junction diode.
ELM - A SIMPLE TOOL FOR THERMAL-HYDRAULIC ANALYSIS OF SOLID-CORE NUCLEAR ROCKET FUEL ELEMENTS
NASA Technical Reports Server (NTRS)
Walton, J. T.
1994-01-01
ELM is a simple computational tool for modeling the steady-state thermal-hydraulics of propellant flow through fuel element coolant channels in nuclear thermal rockets. Written for the nuclear propulsion project of the Space Exploration Initiative, ELM evaluates the various heat transfer coefficient and friction factor correlations available for turbulent pipe flow with heat addition. In the past, these correlations were found in different reactor analysis codes, but now comparisons are possible within one program. The logic of ELM is based on the one-dimensional conservation of energy in combination with Newton's Law of Cooling to determine the bulk flow temperature and the wall temperature across a control volume. Since the control volume is an incremental length of tube, the corresponding pressure drop is determined by application of the Law of Conservation of Momentum. The size, speed, and accuracy of ELM make it a simple tool for use in fuel element parametric studies. ELM is a machine independent program written in FORTRAN 77. It has been successfully compiled on an IBM PC compatible running MS-DOS using Lahey FORTRAN 77, a DEC VAX series computer running VMS, and a Sun4 series computer running SunOS UNIX. ELM requires 565K of RAM under SunOS 4.1, 360K of RAM under VMS 5.4, and 406K of RAM under MS-DOS. Because this program is machine independent, no executable is provided on the distribution media. The standard distribution medium for ELM is one 5.25 inch 360K MS-DOS format diskette. ELM was developed in 1991. DEC, VAX, and VMS are trademarks of Digital Equipment Corporation. Sun4 and SunOS are trademarks of Sun Microsystems, Inc. IBM PC is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation.
An Integrated Software System for Set-Theoretic and Serial Analysis of Contemporary Music.
ERIC Educational Resources Information Center
Harris, Craig R.; Brinkman, Alexander R.
1989-01-01
Describes the Contemporary Music Analysis Package (CMAP), a set of programs for atonal and serial music that is used for analysis, modeling, and composition of contemporary music in an interactive computing environment. The data structure is explained, examples are given, and a glossary of technical terminology is provided. (12 references) (LRW)
ERIC Educational Resources Information Center
Tang, Michael; David, Hyerle; Byrne, Roxanne; Tran, John
2012-01-01
This paper is a mathematical (Boolean) analysis a set of cognitive maps called Thinking Maps[R], based on Albert Upton's semantic principles developed in his seminal works, Design for Thinking (1961) and Creative Analysis (1961). Albert Upton can be seen as a brilliant thinker who was before his time or after his time depending on the future of…
Tanabe, Shigeo; Saitoh, Eiichi; Ohtsuka, Kei; Teranishi, Toshio; Tomita, Yutaka; Muraoka, Yoshihiro
2013-08-01
Recently, three-dimensional (3D) closed curve trajectories of markers placed at strategic body locations, called cyclograms or Lissajous-like graphs, are used for treadmill gait analysis. A simple method is presented to reduce the effect of patient positioning variation. After breaking down movement into three components (anterior-posterior, medial-lateral and superior-inferior), the time-series data and time-inverted data are serially concatenated. A fast Fourier transform (FFT) is done, and a high-pass filter (except 0 Hz) is applied to the anterior-posterior and medial-lateral components. Next an inverse FFT is executed, and the posterior half of the outcome, corresponding to time-inverted data, is deleted. The 3D closed curve is then reconstructed. Results showed that the proposed method was able to reduce the effect of patient positioning variation. Since the adjusted curve is simply a symbolized gait pattern, the method might be useful as an adjunct tool in observational gait analysis. PMID:24765518
NASA Astrophysics Data System (ADS)
Rosén, Tomas; Nordmark, Arne; Aidun, Cyrus K.; Do-Quang, Minh; Lundell, Fredrik
2016-08-01
A spheroidal particle in simple shear flow shows surprisingly complicated angular dynamics; caused by effects of fluid inertia (characterized by the particle Reynolds number Rep) and particle inertia (characterized by the Stokes number St). Understanding this behavior can provide important fundamental knowledge of suspension flows with spheroidal particles. Up to now only qualitative analysis has been available at moderate Rep. Rigorous analytical methods apply only to very small Rep and numerical results lack accuracy due to the difficulty in treating the moving boundary of the particle. Here we show that the dynamics of the rotational motion of a prolate spheroidal particle in a linear shear flow can be quantitatively analyzed through the eigenvalues of the log-rolling particle (particle aligned with vorticity). This analysis provides an accurate description of stable rotational states in terms of Rep,St, and particle aspect ratio (rp). Furthermore we find that the effect on the orientational dynamics from fluid inertia can be modeled with a Duffing-Van der Pol oscillator. This opens up the possibility of developing a reduced-order model that takes into account effects from both fluid and particle inertia.
NASA Astrophysics Data System (ADS)
Borkowski, Andrzej; Kosek, Wiesław
2015-12-01
The paper presents a summary of research activities concerning theoretical geodesy performed in Poland in the period of 2011-2014. It contains the results of research on new methods of the parameter estimation, a study on robustness properties of the M-estimation, control network and deformation analysis, and geodetic time series analysis. The main achievements in the geodetic parameter estimation involve a new model of the M-estimation with probabilistic models of geodetic observations, a new Shift-Msplit estimation, which allows to estimate a vector of parameter differences and the Shift-Msplit(+) that is a generalisation of Shift-Msplit estimation if the design matrix A of a functional model has not a full column rank. The new algorithms of the coordinates conversion between the Cartesian and geodetic coordinates, both on the rotational and triaxial ellipsoid can be mentioned as a highlights of the research of the last four years. New parameter estimation models developed have been adopted and successfully applied to the control network and deformation analysis. New algorithms based on the wavelet, Fourier and Hilbert transforms were applied to find time-frequency characteristics of geodetic and geophysical time series as well as time-frequency relations between them. Statistical properties of these time series are also presented using different statistical tests as well as 2nd, 3rd and 4th moments about the mean. The new forecasts methods are presented which enable prediction of the considered time series in different frequency bands.
Tutorial: survival analysis--a statistic for clinical, efficacy, and theoretical applications.
Gruber, F A
1999-04-01
Current demands for increased research attention to therapeutic efficacy, efficiency, and also for improved developmental models call for analysis of longitudinal outcome data. Statistical treatment of longitudinal speech and language data is difficult, but there is a family of statistical techniques in common use in medicine, actuarial science, manufacturing, and sociology that has not been used in speech or language research. Survival analysis is introduced as a method that avoids many of the statistical problems of other techniques because it treats time as the outcome. In survival analysis, probabilities are calculated not just for groups but also for individuals in a group. This is a major advantage for clinical work. This paper provides a basic introduction to nonparametric and semiparametric survival analysis using speech outcomes as examples. A brief discussion of potential conflicts between actuarial analysis and clinical intuition is also provided. PMID:10229458
A simple method for global sequence comparison.
Pizzi, E; Attimonelli, M; Liuni, S; Frontali, C; Saccone, C
1992-01-01
A simple method of sequence comparison, based on a correlation analysis of oligonucleotide frequency distributions, is here shown to be a reliable test of overall sequence similarity. The method does not involve sequence alignment procedures and permits the rapid screening of large amounts of sequence data. It identifies those sequences which deserve more careful analysis of sequence similarity at the level of resolution of the single nucleotide. It uses observed quantities only and does not involve the adoption of any theoretical model. PMID:1738591
NASA Technical Reports Server (NTRS)
Faghri, Amir; Swanson, Theodore D.
1988-01-01
The results of a numerical computation and theoretical analysis are presented for the flow of a thin liquid film in the presence and absence of a gravitational body force. Five different flow systems were used. Also presented are the governing equations and boundary conditions for the situation of a thin liquid emanating from a pressure vessel; traveling along a horizontal plate with a constant initial height and uniform initial velocity; and traveling radially along a horizontal disk with a constant initial height and uniform initial velocity.
NASA Technical Reports Server (NTRS)
Tower, L. K.
1973-01-01
The diffusion of oxygen into, or out of, a gettered alloy exposed to oxygenated alkali liquid metal coolant, a situation arising in some high temperature heat transfer systems, was analyzed. The relation between the diffusion process and the thermochemistry of oxygen in the alloy and in the alkali metal was developed by making several simplifying assumptions. The treatment is therefore theoretical in nature. However, a practical example pertaining to the startup of a heat pipe with walls of T-111, a tantalum alloy, and lithium working fluid illustrates the use of the figures contained in the analysis.
NASA Astrophysics Data System (ADS)
Durlak, Piotr; Berski, Sławomir; Latajka, Zdzisław
2016-01-01
The molecular structure, conformational preferences, topological and vibrational analysis of allicin has been investigated at two different approaches. Calculations have been carried out on static (DFT and MP2) levels with an assortment of Dunning's basis sets and dynamic CPMD simulations. In this both case within the isolated molecule approximation. The results point out that at least twenty different conformers coexist on the PES as confirmed by the flexible character of this molecule. The topological analysis of ELF showed very similar nature of the Ssbnd S and Ssbnd O bonds. The infrared spectrum has been calculated, and a comparative vibrational analysis has been performed.
Azhagiri, Sachidanandam; Ramkumaar, Govindaswamy Ranganathan; Jayakumar, Suryanarayan; Kumaresan, Subramanian; Arunbalaji, Ramadoss; Gunasekaran, Sethu; Srinivasan, Shanmugam
2010-01-01
The FTIR spectrum of 2-nitroaniline was recorded in the regions 4000-400 cm(-1). The optimized molecular geometry, bond orders, atomic charges, harmonic vibrational wave numbers and intensities of vibrational bands of 2-nitroaniline and its cation were calculated at DFT levels invoking two different basis sets 6-31G and 6-31+G using Gaussian 03W program. The X-ray geometry and FTIR vibrational frequencies were compared with the results of DFT calculations. The thermal stability of 2NA is studied by the thermo gravimetric analysis (TGA). Experimental degradation process of 2-nitroaniline was interpreted with the bond order analysis. The Mulliken atomic charge analysis was also made in the present study. Based on the molecular geometry and Mulliken charge analysis, intra molecular hydrogen bonding was identified. PMID:19504134
Moyib, O K; Mkumbira, J; Odunola, O A; Dixon, A G
2012-12-01
Cyanogenic potential (CNp) of cassava constitutes a serious problem for over 500 million people who rely on the crop as their main source of calories. Genetic diversity is a key to successful crop improvement for breeding new improved variability for target traits. Forty-three improved genotypes of cassava developed by International Institute of Tropical Agriculture (ITA), Ibadan, were characterized for CNp trait using 35 Simple Sequence.Repeat (SSR) markers. Essential colorimetry picric test was used for evaluation of CNp on a color scale of 1 to 14. The CNp scores obtained ranged from 3 to 9, with a mean score of 5.48 (+/- 0.09) based on Statistical Analysis System (SAS) package. TMS M98/ 0068 (4.0 +/- 0.25) was identified as the best genotype with low CNp while TMS M98/0028 (7.75 +/- 0.25) was the worst. The 43 genotypes were assigned into 7 phenotypic groups based on rank-sum analysis in SAS. Dissimilarity analysis representatives for windows generated a phylogenetic tree with 5 clusters which represented hybridizing groups. Each of the clusters (except 4) contained low CNp genotypes that could be used for improving the high CNp genotypes in the same or near cluster. The scatter plot of the genotypes showed that there was little or no demarcation for phenotypic CNp groupings in the molecular groupings. The result of this study demonstrated that SSR markers are powerful tools for the assessment of genetic variability, and proper identification and selection of parents for genetic improvement of low CNp trait among the IITA cassava collection. PMID:23678653
Technology Transfer Automated Retrieval System (TEKTRAN)
A simple, fast, and cost-effective sample preparation method, previously developed and validated for the analysis of organic contaminants in fish using low-pressure gas chromatography tandem mass spectrometry (LPGC-MS/MS), was evaluated for analysis of polybrominated diphenyl ethers (PBDEs) and dich...
Jones, Patrick; Alzweri, Laith; Rai, Bhavan Prasad; Somani, Bhaskar K.; Bates, Chris; Aboumarzouk, Omar M.
2015-01-01
Objective To compare and evaluate the safety and efficacy of holmium laser enucleation of the prostate (HoLEP) and simple prostatectomy for large prostate burdens, as discussion and debate continue about the optimal surgical intervention for this common pathology. Materials and methods A systematic search was conducted for studies comparing HoLEP with simple prostatectomy [open (OP), robot-assisted, laparoscopic] using a sensitive strategy and in accordance with Cochrane collaboration guidelines. Primary parameters of interest were objective measurements including maximum urinary flow rate (Qmax) and post-void residual urine volume (PVR), and subjective outcomes including International Prostate Symptom Score (IPSS) and quality of life (QoL). Secondary outcomes of interest included volume of tissue retrieved, catheterisation time, hospital stay, blood loss and serum sodium decrease. Data on baseline characteristics and complications were also collected. Where possible, comparable data were combined and meta-analysis was conducted. Results In all, 310 articles were identified and after screening abstracts (114) and full manuscripts (14), three randomised studies (263 patients) were included, which met our pre-defined inclusion criteria. All these compared HoLEP with OP. The mean transrectal ultrasonography (TRUS) volume was 113.9 mL in the HoLEP group and 119.4 mL in the OP group. There was no statistically significant difference in Qmax, PVR, IPSS and QoL at 12 and 24 months between the two interventions. OP was associated with a significantly shorter operative time (P = 0.01) and greater tissue retrieved (P < 0.001). However, with HoLEP there was significantly less blood loss (P < 0.001), patients had a shorter hospital stay (P = 0.03), and were catheterised for significantly fewer hours (P = 0.01). There were no significant differences in the total number of complications recorded amongst HoLEP and OP (P = 0.80). Conclusion The results of the meta-analysis
The design of an optimal fog water collector: A theoretical analysis
NASA Astrophysics Data System (ADS)
Regalado, Carlos M.; Ritter, Axel
2016-09-01
We investigate the collection efficiency of different fog water catchers assemblies (mainly flat and cylindrical structures equipped with several screens of staggered filaments) by means of parametric equations which take into consideration both impaction and aerodynamic effects. We introduce different models that vary in complexity and range of applicability, and may be used to analyze the effect that geometry, number of screens, spacing and inclination of the filament strands have on the fog water yield of the collector. Increasing the number of impacting screens, nR, is shown to improve the collection efficiency up to an optimum for nR = 3-5; beyond nR > 5 impermeability to the airflow makes the fog catcher less efficient. Geometry of the collector is shown to be relatively important: unless wind direction varies widely, the rectangular flat design is preferred over the cylindrical one, because of its larger drag, i.e. increased aerodynamic efficiency, ηa. In fact ηa is shown to be limiting, such that values over ηa > 50% are difficult to attain. By contrast the impaction efficiency, ηimp, of fog water droplets onto multiple nR parallel screens of filaments may reach theoretical values of ηimp > 80%. Inclination of the impacting screens over the vertical may slightly reduce ηimp, but this may be compensated by a reduction in flow resistance, i.e. increased aerodynamic efficiency.
NASA Astrophysics Data System (ADS)
Zhou, Hai-An; Wang, Xiao-Ming; Mei, Yu-Lin
2014-10-01
The vibro-acoustic responses and sound absorption characteristics of two kinds of periodically stiffened micro-perforated plates are analyzed theoretically. The connected periodical structures of the stiffened plates can be ribs or block-like structures. Based on fundamental acoustic formulas of the micro-perforated plate of Maa and Takahashi, semi-analytical models of the vibrating stiffened plates are developed in this paper. Approaches like the space harmonicmethod, Fourier transforms and finite elementmethod (FEM) are adopted to investigate both kinds of the stiffened plates. In the present work, the vibro-acoustic responses of micro-perforated stiffened plates in the wavenumber space are expressed as functions of plate displacement amplitudes. After approximate numerical solutions of the amplitudes, the vibration equations and sound absorption coefficients of the two kinds of stiffened plates in the physical space are then derived by employing the Fourier inverse transform. In numerical examples, the effects of some physical parameters, such as the perforation ratio, incident angles and periodical distances etc., on the sound absorption performance are examined. The proposed approaches are also validated by comparing the present results with solutions of Takahashi and previous studies of stiffened plates. Numerical results indicate that the flexural vibration of the plate has a significant effect on the sound absorption coefficient in the water but has little influence in the air.
Yuan, Yi; Chen, Yudong; Li, Xiaoli
2016-01-01
Transcranial magneto-acoustical stimulation (TMAS) is a novel stimulation technology in which an ultrasonic wave within a magnetostatic field generates an electric current in an area of interest in the brain to modulate neuronal activities. As a key part of the neural network, neurons transmit information in the nervous system. However, the effect of TMAS on the neuronal firing pattern remains unknown. To address this problem, we investigated the stimulatory mechanism of TMAS on neurons, by using a Hodgkin-Huxley neuron model. The simulation results indicated that the magnetostatic field intensity and ultrasonic power affect the amplitude and interspike interval of neuronal action potential under a continuous wave ultrasound. The simulation results also showed that the ultrasonic power, duty cycle and repetition frequency can alter the firing pattern of neural action potential under pulsed wave ultrasound. This study may help to reveal and explain the biological mechanism of TMAS and to provide a theoretical basis for TMAS in the treatment or rehabilitation of neuropsychiatric disorders. PMID:27148032
Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E.; Souza, Valeria; Soberón-Chávez, Gloria
2015-01-01
Many strains of bacteria produce antagonistic substances that restrain the growth of others, and potentially give them a competitive advantage. These substances are commonly released to the surrounding environment, involving metabolic costs in terms of energy and nutrients. The rate at which these molecules need to be produced to maintain a certain amount of them close to the producing cell before they are diluted into the environment has not been explored so far. To understand the potential cost of production of antagonistic substances in water environments, we used two different theoretical approaches. Using a probabilistic model, we determined the rate at which a cell needs to produce individual molecules in order to keep on average a single molecule in its vicinity at all times. For this minimum protection, a cell would need to invest 3.92 × 10−22 kg s−1 of organic matter, which is 9 orders of magnitude lower than the estimated expense for growth. Next, we used a continuous model, based on Fick's laws, to explore the production rate needed to sustain minimum inhibitory concentrations around a cell, which would provide much more protection from competitors. In this scenario, cells would need to invest 1.20 × 10−11 kg s−1, which is 2 orders of magnitude higher than the estimated expense for growth, and thus not sustainable. We hypothesize that the production of antimicrobial compounds by bacteria in aquatic environments lies between these two extremes. PMID:26074891
A theoretical analysis of stress wave propagation in the head under primary blast loading.
Zhu, Feng; Chou, Clifford C; Yang, King H; King, Albert I
2014-04-01
Traumatic brain injury due to primary blast loading has become a signature injury in recent military conflicts. Efforts have been made to study the stress wave propagation in the head. However, the relationship of incident pressure, reflected pressure and intracranial pressure is still not clear, and the experimental findings reported in the literature are contradictory. In this article, an analytical model is developed to calculate the stress wave transfer through a multiple-layered structure which is used to mimic the head. The model predicts stress at the scalp-skull and skull-brain interfaces as the functions of reflected pressure, which is further dependent on incident pressure. A numerical model is used to corroborate the theoretical predictions. It is concluded that scalp has an amplification effect on intracranial pressure. If scalp is absent, there exists a critical incident pressure, defined as P cr at approximately 16 kPa. When peak incident pressure σ in is higher than 16 kPa, the pressure at the skull-brain interface is greater than σ in; otherwise, it is lower than σ in. PMID:24718865
When microbes and consumers determine the limiting nutrient of autotrophs: a theoretical analysis
Cherif, Mehdi; Loreau, Michel
2008-01-01
Ecological stoichiometry postulates that differential nutrient recycling of elements such as nitrogen and phosphorus by consumers can shift the element that limits plant growth. However, this hypothesis has so far considered the effect of consumers, mostly herbivores, out of their food-web context. Microbial decomposers are important components of food webs, and might prove as important as consumers in changing the availability of elements for plants. In this theoretical study, we investigate how decomposers determine the nutrient that limits plants, both by feeding on nutrients and organic carbon released by plants and consumers, and by being fed upon by omnivorous consumers. We show that decomposers can greatly alter the relative availability of nutrients for plants. The type of limiting nutrient promoted by decomposers depends on their own elemental composition and, when applicable, on their ingestion by consumers. Our results highlight the limitations of previous stoichiometric theories of plant nutrient limitation control, which often ignored trophic levels other than plants and herbivores. They also suggest that detrital chains play an important role in determining plant nutrient limitation in many ecosystems. PMID:18854301
Frequency-dependent seismic attenuation in shales: experimental results and theoretical analysis
NASA Astrophysics Data System (ADS)
Delle Piane, Claudio; Sarout, Joel; Madonna, Claudio; Saenger, Erik H.; Dewhurst, David N.; Raven, Mark
2014-07-01
Samples of shales from the Ordovician Bongabinni and Goldwyer source rock formations were recovered from the Canning Basin (Western Australia). Attenuation was experimentally measured on preserved plugs from these formations in the frequency range between 10-2 and 102 Hz. Samples cored with different orientations with respect to the sedimentary bedding were prepared and tested in their native saturated state and after drying in the oven at 105 °C for 24 hr to assess the effect of fluids and of the sediment anisotropy on attenuation. To aid the interpretation of the experimental results, the clay-rich samples were characterized in terms of mineralogy, water content, porosity, permeability and microstructure. The two shales have significantly different quality factors; and this is seen to be dependent on both the saturation state of the samples and the propagation direction of the oscillatory signal. The attenuation coefficient for compression/extension parallel to bedding is less than that vertical to bedding in both the preserved and partially dehydrated situations. No frequency dependency is observed in the preserved samples within the range of frequencies explored in this study. On the other hand partially saturated samples show peaks in attenuation at around 40 Hz when the stress perturbation is transmitted normal to the macroscopic bedding. The interpretation of the attenuation measurements in terms of well-established theoretical models is discussed in view of the physical characteristics and microstructure of the tested rocks.
Bribe and Punishment: An Evolutionary Game-Theoretic Analysis of Bribery
Verma, Prateek; Sengupta, Supratim
2015-01-01
Harassment bribes, paid by citizens to corrupt officers for services the former are legally entitled to, constitute one of the most widespread forms of corruption in many countries. Nation states have adopted different policies to address this form of corruption. While some countries make both the bribe giver and the bribe taker equally liable for the crime, others impose a larger penalty on corrupt officers. We examine the consequences of asymmetric and symmetric penalties by developing deterministic and stochastic evolutionary game-theoretic models of bribery. We find that the asymmetric penalty scheme can lead to a reduction in incidents of bribery. However, the extent of reduction depends on how the players update their strategies over time. If the interacting members change their strategies with a probability proportional to the payoff of the alternative strategy option, the reduction in incidents of bribery is less pronounced. Our results indicate that changing from a symmetric to an asymmetric penalty scheme may not suffice in achieving significant reductions in incidents of harassment bribery. PMID:26204110
Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E; Souza, Valeria; Soberón-Chávez, Gloria
2015-01-01
Many strains of bacteria produce antagonistic substances that restrain the growth of others, and potentially give them a competitive advantage. These substances are commonly released to the surrounding environment, involving metabolic costs in terms of energy and nutrients. The rate at which these molecules need to be produced to maintain a certain amount of them close to the producing cell before they are diluted into the environment has not been explored so far. To understand the potential cost of production of antagonistic substances in water environments, we used two different theoretical approaches. Using a probabilistic model, we determined the rate at which a cell needs to produce individual molecules in order to keep on average a single molecule in its vicinity at all times. For this minimum protection, a cell would need to invest 3.92 × 10(-22) kg s(-1) of organic matter, which is 9 orders of magnitude lower than the estimated expense for growth. Next, we used a continuous model, based on Fick's laws, to explore the production rate needed to sustain minimum inhibitory concentrations around a cell, which would provide much more protection from competitors. In this scenario, cells would need to invest 1.20 × 10(-11) kg s(-1), which is 2 orders of magnitude higher than the estimated expense for growth, and thus not sustainable. We hypothesize that the production of antimicrobial compounds by bacteria in aquatic environments lies between these two extremes. PMID:26074891
A theoretical basis for the analysis of redundant software subject to coincident errors
NASA Technical Reports Server (NTRS)
Eckhardt, D. E., Jr.; Lee, L. D.
1985-01-01
Fundamental to the development of redundant software techniques fault-tolerant software, is an understanding of the impact of multiple-joint occurrences of coincident errors. A theoretical basis for the study of redundant software is developed which provides a probabilistic framework for empirically evaluating the effectiveness of the general (N-Version) strategy when component versions are subject to coincident errors, and permits an analytical study of the effects of these errors. The basic assumptions of the model are: (1) independently designed software components are chosen in a random sample; and (2) in the user environment, the system is required to execute on a stationary input series. The intensity of coincident errors, has a central role in the model. This function describes the propensity to introduce design faults in such a way that software components fail together when executing in the user environment. The model is used to give conditions under which an N-Version system is a better strategy for reducing system failure probability than relying on a single version of software. A condition which limits the effectiveness of a fault-tolerant strategy is studied, and it is posted whether system failure probability varies monotonically with increasing N or whether an optimal choice of N exists.
Physical mapping of complex genomes by sampled sequencing: A theoretical analysis
Kupfer, K.; Smith, M.; Quackenbush, J.
1995-05-01
A method for high-throughput, high-resolution physical mapping of complex genomes and human chromosomes called Genomic Sequence Sampling (GSS) has recently been proposed. This mapping strategy employs high-density cosmid contig assembly over 200-kb to 1-Mb regions of the target genome coupled with DNA sequencing of the cosmid ends. The relative order and spacing of the sequence fragments is determined from the template contig, resulting in a physical map of 1-to 5-kb resolution that contains a substantial portion of the entire sequence at one-pass accuracy. The purpose of this paper is to determine the theoretical parameters for GSS mapping, to evaluate the effectiveness of the contig-building strategy, and to calculate the expected fraction of the target genome that can be recovered as mapped sequence. A novel aspect of the cosmid fingerprinting and contig-building strategy involves determining the orientation of the genomic inserts relative to the cloning vectors, so that the sampled sequence fragments can be mapped with high resolution. The algorithm is based upon complete restriction enzyme digestion, contig assembly by matching fragments, and end-orientation of individual cosmids by determining the best consistent fit of the labeled cosmid end fragments in the consensus restriction map. 32 refs., 7 figs.
Combination of real options and game-theoretic approach in investment analysis
NASA Astrophysics Data System (ADS)
Arasteh, Abdollah
2016-02-01
Investments in technology create a large amount of capital investments by major companies. Assessing such investment projects is identified as critical to the efficient assignment of resources. Viewing investment projects as real options, this paper expands a method for assessing technology investment decisions in the linkage existence of uncertainty and competition. It combines the game-theoretic models of strategic market interactions with a real options approach. Several key characteristics underlie the model. First, our study shows how investment strategies rely on competitive interactions. Under the force of competition, firms hurry to exercise their options early. The resulting "hurry equilibrium" destroys the option value of waiting and involves violent investment behavior. Second, we get best investment policies and critical investment entrances. This suggests that integrating will be unavoidable in some information product markets. The model creates some new intuitions into the forces that shape market behavior as noticed in the information technology industry. It can be used to specify best investment policies for technology innovations and adoptions, multistage R&D, and investment projects in information technology.
Theoretical Analysis of Neutron and X-ray Scattering Data on 3He
NASA Astrophysics Data System (ADS)
Krotscheck, E.; Panholzer, M.
2011-04-01
X-ray scattering experiments on bulk liquid 3He (Albergamo et al. in Phys. Rev. Lett. 99:205301, 2007; Schmets and Montfrooij in Phys. Rev. Lett. 100:239601, 2008; Albergamo et al. in Phys. Rev. Lett. 100:239602, 2008) have indicated the possibility of the existence of a sharp collective mode at large momentum transfers. We address this issue within a manifestly microscopic theory of excitations in a Fermi fluid that can be understood as proper generalization of the time-honored theory of Jackson, Feenberg, and Campbell (Jackson in Phys. Rev. A 8:1529, 1973; Feenberg in Theory of Quantum Fluids, 1969; Chang and Campbell in Phys. Rev. B 13:3779, 1976) of excitations in 4He. We show that both neutron and X-ray data can be well explained within a theory where the high momentum excitations lie in fact inside the particle-hole continuum. "Pair fluctuations" contribute a sharpening of the mode compared to the random phase approximation (RPA). When the theoretical results are convoluted with the experimental resolution, the agreement between theory and X-ray data is quite good.
Asah, Stanley Tanyi
2008-12-01
The social-ecological system (SES) approach to natural resource management holds enormous promise towards achieving sustainability. Despite this promise, social-ecological interactions are complex and elusive; they require simplification to guide effective application of the SES approach. The complex, adaptive and place-specific nature of human-environment interactions impedes determination of state and trends in SES parameters of interest to managers and policy makers. Based on a rigorously developed systemic theoretical model, this paper integrates field observations, interviews, surveys, and latent variable modeling to illustrate the development of simplified and easily interpretable indicators of the state of, and trends in, relevant SES processes. Social-agricultural interactions in the Logone floodplain, in the Lake Chad basin, served as case study. This approach is found to generate simplified determinants of the state of SESs, easily communicable across the array of stakeholders common in human-environment interactions. The approach proves to be useful for monitoring SESs, guiding interventions, and assessing the effectiveness of interventions. It incorporates real time responses to biophysical change in understanding coarse scale processes within which finer scales are embedded. This paper emphasizes the importance of merging quantitative and qualitative methods for effective monitoring and assessment of SESs. PMID:18773239
The role of narrative and metaphor in the cancer life story: a theoretical analysis.
Laranjeira, Carlos
2013-08-01
Being diagnosed with cancer can be one of those critical incidents that negatively affect the self. Identity is threatened when physical, psychological, and social consequences of chronic illness begin to erode one's sense of self and challenge an individual's ability to continue to present the self he or she prefers to present to others. Based on the notion of illness trajectory and adopting a Ricoeurian narrative perspective, this theoretical paper shall explore the impact of cancer disease on identity and establish the crucial importance of metaphor in the narratives of life with cancer. Findings indicate that in cancer narratives the illness experience supplies the narrative structure with temporal and spatial meeting points that make the narrative comprehensible and meaningful. Cancer forces identity changes not only from having to endure the long-term physical and psychosocial effects of the disease, but also from inevitable existential questions about life's meaning. Improved medical knowledge today means improved ethnomedical practices. Metaphor can bridge the gap between the cancer experience and the world of technology and treatment, helping patients to symbolically control their illness. PMID:23054424
Theoretical analysis of effects of boundary layer bleed on scramjet thrust
NASA Astrophysics Data System (ADS)
Yue, LianJie; Xu, XianKun; Chang, XinYu
2013-10-01
The effects of boundary layer bleed on the scramjet thrust are studied in the present paper. A theoretical model is developed to evaluate the thrust increment and influencing factors. The thrust increment resulting from the bleed is dominated by the rise in total pressure recovery and bleed mass flow rate. The bleed mass flow rate exerts stronger impact on the engine thrust than the total pressure. According to current bleed design, it is a severe challenge for the engine to enhance its total pressure to maintain the original thrust when there is no bleeding. Furthermore, the initial total pressure recovery, fuel mass addition, combustion efficiency and area ratio of engine exit to entrance can affect the contributions of the bleeding to the thrust increment. The scramjet needs a higher rise in total pressure recovery to counteract the negative effect of bleed mass loss at higher initial total pressure recovery or larger area ratio of engine exit/entrance. More heat release results in a little lower demand on the rise in total pressure recovery for maintaining the scramjet thrust. These results will aid in understanding the fundamental mechanism of bleeding on engine thrust.
Baier, Jürgen; Fuss, Thomas; Pöllmann, Claudia; Wiesmann, Christopher; Pindl, Katrin; Engl, Roland; Baumer, Daniela; Maier, Max; Landthaler, Michael; Bäumler, Wolfgang
2007-06-26
After the generation by different photosensitizers, the direct detection of singlet oxygen is performed by measuring its luminescence at 1270 nm. Using an infrared sensitive photomultiplier, the complete rise and decay time of singlet oxygen luminescence is measured at different concentrations of a photosensitizer, quencher, or oxygen. This allows the extraction of important information about the photosensitized generation of singlet oxygen and its decay, in particular at different oxygen concentrations. Based on theoretical considerations all important relaxation rates and rate constants were determined for the triplet T(1) states of the photosensitizers and for singlet oxygen. In particular, depending on the oxygen or quencher concentration, the rise or the decay time of the luminescence signal exhibit different meanings regarding the lifetime of singlet oxygen or triplet T(1)-state. To compare with theory, singlet oxygen was generated by nine different photosensitizers dissolved in either H2O, D2O or EtOD. When using H2O as solvent, the decaying part of the luminescence signal is frequently not the lifetime of singlet oxygen, in particular at low oxygen concentration. Since cells show low oxygen concentrations, this must have an impact when looking at singlet oxygen detection in vitro or in vivo. PMID:17482831