12,189 research outputs found
A microfluidic device for the study of the orientational dynamics of microrods
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
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
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
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 , where 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
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
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
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
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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