12,189 research outputs found

    A microfluidic device for the study of the orientational dynamics of microrods

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    We describe a microfluidic device for studying the orientational dynamics of microrods. The device enables us to experimentally investigate the tumbling of microrods immersed in the shear flow in a microfluidic channel with a depth of 400 mu and a width of 2.5 mm. The orientational dynamics was recorded using a 20 X microscopic objective and a CCD camera. The microrods were produced by shearing microdroplets of photocurable epoxy resin. We show different examples of empirically observed tumbling. On the one hand we find that short stretches of the experimentally determined time series are well described by fits to solutions of Jeffery's approximate equation of motion [Jeffery, Proc. R. Soc. London. 102 (1922), 161-179]. On the other hand we find that the empirically observed trajectories drift between different solutions of Jeffery's equation. We discuss possible causes of this orbit drift.Comment: 11 pages, 8 figure

    Relationship between earthquake fault triggering and societal behavior using ant colony optimization

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    In this analysis, we use the ant behaviour in simulating a framework for analysis of complex interplay amongst short time-scale deformation, long time- scale tectonics for positive stress coupling and slip interactions in earthquake genesis modeling. Using the proposed improved ant colony algorithm for global optimization the best solution ants within the search and the circulation of the optimal solution as the initial solution search, to expand its search, to avoid falling into local optimum  of  trigger zones analysis for earthquake occurrences. In order to validate the avalanche behaviour and corresponding nucleation we  best solution as the initial solution is adopted in order to widen searching scope to avoid getting into local optimum . In this proposed framework, an ant colony model is simulated to identify the physical framework of identifying trigger basins for the precursors to geodynamic model of propagation for precursory stress-strain signals. The disturbances at trigger basins cause the collapse of a subsystem leading to stress evolution and slip nucleation. Trigger basins help identify the zone of earthquake source nucleation as an index of ? and ? for strain analysis. The stress strain network can be interpreted by the increase in steady-state energy transmitted due to redistribution of stress accumulation into the earth tectonic framework. Sand pile behaviour model has been modeled through ant colony optimization for forecasting of likelihood time of triggering influences of lithosphere on the basis of critical zones of lithosphere where dump of elastic pressure is possible. The ant colony adaptive framework consisted of vertices representing the stress-strain component and edges, representing scored transformations for global coupling effects have been constructed for dynamic monitoring of stress and strain behaviour. Triggering basins serve as harbingers of large earthquake where stress-strain interactions have been analyzed by the quasi-static mechanics of seismic precursory stress-strain propagation in the crustal lithosphere. The study shows that dynamic variation of stress drop due to saved up pressure can be modeled by ant colony framework for steady state release due to trigger and global correlation framework. The simulation framework shows that with time, spatial triggering points can be negatively coupled and these interact with lesser impact, while positive coupling occurs only with more distant zones of stress generation for geodynamic frameworks, suggesting that the structural heterogeneities within the causative rocks associated with cracks and pores can dictate the pattern of stress – strain interactions and earthquake generating processes. Keywords: crack–porous, ant colony, geo-dynamical framework, stress-strain transmission, emergenc

    Synthesis, Spectral and Antibacterial Studies of Binuclear Titanium(IV) / Zirconium(IV) Complexes of Piperazine Dithiosemicarbazones

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    The reactions of mono(cyclopentadienyl)titanium(IV) trichloride and bis(cyclopentadienyl)titanium(IV)/ zirconium(IV) dichloride with a new class of dithiosemicarbazone, derived by condensing piperazine dithiosemicarbazide with benzaldehyde (L1H2), 2-chlorobenzaldehyde (L2H2), 4-nitrobenzaldehyde (L3H2) or salicylaldehyde (L4H4) have been studied and different types of binuclear products, viz. [{CpTiCl2}2L], [{Cp2MCl}2L], ((L=L1, L2 or L3), [{CpTiCI}2L4] and [{Cp2M}2L4] (M=Yi or Zr), have been isolated. Tentative structures are proposed for these complexes based upon elemental analyses, electrical conductance, magnetic moment and spectral (electronic, IR, 1H and 13C NMR) data. Attempts have been made to establish a correlation between antibacterial activity and the structures of the products

    Private Incremental Regression

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    Data is continuously generated by modern data sources, and a recent challenge in machine learning has been to develop techniques that perform well in an incremental (streaming) setting. In this paper, we investigate the problem of private machine learning, where as common in practice, the data is not given at once, but rather arrives incrementally over time. We introduce the problems of private incremental ERM and private incremental regression where the general goal is to always maintain a good empirical risk minimizer for the history observed under differential privacy. Our first contribution is a generic transformation of private batch ERM mechanisms into private incremental ERM mechanisms, based on a simple idea of invoking the private batch ERM procedure at some regular time intervals. We take this construction as a baseline for comparison. We then provide two mechanisms for the private incremental regression problem. Our first mechanism is based on privately constructing a noisy incremental gradient function, which is then used in a modified projected gradient procedure at every timestep. This mechanism has an excess empirical risk of d\approx\sqrt{d}, where dd is the dimensionality of the data. While from the results of [Bassily et al. 2014] this bound is tight in the worst-case, we show that certain geometric properties of the input and constraint set can be used to derive significantly better results for certain interesting regression problems.Comment: To appear in PODS 201

    Path Integrals for Parastatistics

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    We demonstrate that parastatistics can be quantized using path integrals by calculating the generating functionals for time-ordered products of both free and interacting parabose and parafermi fields in terms of path integrals. We also give a convenient form of the commutation relations for the Green components of the parabose and parafermi operators in both the canonical and path integral formalisms.Comment: typos corrected, references added, some new content. version that has been publishe

    Joint Segmentation and Uncertainty Visualization of Retinal Layers in Optical Coherence Tomography Images using Bayesian Deep Learning

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    Optical coherence tomography (OCT) is commonly used to analyze retinal layers for assessment of ocular diseases. In this paper, we propose a method for retinal layer segmentation and quantification of uncertainty based on Bayesian deep learning. Our method not only performs end-to-end segmentation of retinal layers, but also gives the pixel wise uncertainty measure of the segmentation output. The generated uncertainty map can be used to identify erroneously segmented image regions which is useful in downstream analysis. We have validated our method on a dataset of 1487 images obtained from 15 subjects (OCT volumes) and compared it against the state-of-the-art segmentation algorithms that does not take uncertainty into account. The proposed uncertainty based segmentation method results in comparable or improved performance, and most importantly is more robust against noise

    Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13-14 June 2012

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    We report on the kinematics of two interacting CMEs observed on 13 and 14 June 2012. Both CMEs originated from the same active region NOAA 11504. After their launches which were separated by several hours, they were observed to interact at a distance of 100 Rs from the Sun. The interaction led to a moderate geomagnetic storm at the Earth with Dst index of approximately, -86 nT. The kinematics of the two CMEs is estimated using data from the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard the Solar Terrestrial Relations Observatory (STEREO). Assuming a head-on collision scenario, we find that the collision is inelastic in nature. Further, the signatures of their interaction are examined using the in situ observations obtained by Wind and the Advance Composition Explorer (ACE) spacecraft. It is also found that this interaction event led to the strongest sudden storm commencement (SSC) (approximately 150 nT) of the present Solar Cycle 24. The SSC was of long duration, approximately 20 hours. The role of interacting CMEs in enhancing the geoeffectiveness is examined.Comment: 17 pages, 5 figures, Accepted in Solar Physics Journa

    Genetic and Multilocation Evaluation of High Yielding Provenances of Bhimal (\u3cem\u3eGrewia optiva\u3c/em\u3e) on Farmers’ Fields in North Western Himalayas

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    Agroforestry is the inclusion of woody perennial within farming systems, has been practiced as a traditional land use and livelihood option since time immemorial (FSI 2013). It is being practiced on agricultural lands for fuel wood and fodder (Khybri et al., 1992), as well as medicinal and fruit trees (Bijalwan, 2011; Rathore et al., 2014) enabling food security (Narain 1998), non timber forest products, timber and shelter etc. A number of different (185) agroforestry systems are popular among farmers in different agro-climatic regions (Solanki, 2006). Grewia optiva Drummond (Bhimal) is an important agroforestry tree species primarily grown for green fodder in the north west Himalayas (Khybri et al., 1992; Dhyani, 2009). It is distributed throughout the sub-Himalayan tract upto an altitude of 1800m. Therefore, the present study was envisaged to monitor the performance of three best provenances of Bhimal (Mehta et al., 2011) on farmers’ fields at four locations comprising middle hill elevations and valley zones and their effect on field crops
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