1,525 research outputs found
Protecting traditional ethno-botanical knowledge in South Africa through the intellectual property regime
Traditional knowledge has been used, and is increasingly being used, in a wide range of industries for the development of new products. Increasing awareness of the economic value of biological diversity has resulted in industries seeking to exploit traditional knowledge and biodiversity through opportunistic behaviour (biopiracy). This is also happening in South Africa, where numerous industries are developing new products. Recent advances in the field of biotechnology have created the need for greater intellectual property rights protection. The protection of traditional knowledge has however long been ignored as developed nations and large industries have sought to promote self-serving systems of protection. In this paper the example of an indigenous medicinal plant is used to analyse and describe the extent to which patent and trademark protection is able to protect traditional ethno-botanical knowledge in South Africa. The study therefore aims to contribute to an understanding of the value that traditional knowledge holds for the sustainable development and economic growth of communities, and how such knowledge can be protected.Research and Development/Tech Change/Emerging Technologies,
Target Mass Monitoring and Instrumentation in the Daya Bay Antineutrino Detectors
The Daya Bay experiment measures sin^2 2{\theta}_13 using functionally
identical antineutrino detectors located at distances of 300 to 2000 meters
from the Daya Bay nuclear power complex. Each detector consists of three nested
fluid volumes surrounded by photomultiplier tubes. These volumes are coupled to
overflow tanks on top of the detector to allow for thermal expansion of the
liquid. Antineutrinos are detected through the inverse beta decay reaction on
the proton-rich scintillator target. A precise and continuous measurement of
the detector's central target mass is achieved by monitoring the the fluid
level in the overflow tanks with cameras and ultrasonic and capacitive sensors.
In addition, the monitoring system records detector temperature and levelness
at multiple positions. This monitoring information allows the precise
determination of the detectors' effective number of target protons during data
taking. We present the design, calibration, installation and in-situ tests of
the Daya Bay real-time antineutrino detector monitoring sensors and readout
electronics.Comment: 22 pages, 20 figures; accepted by JINST. Changes in v2: minor
revisions to incorporate editorial feedback from JINS
Applying Bayesian Neural Networks to Separate Neutrino Events from Backgrounds in Reactor Neutrino Experiments
A toy detector has been designed to simulate central detectors in reactor
neutrino experiments in the paper. The samples of neutrino events and three
major backgrounds from the Monte-Carlo simulation of the toy detector are
generated in the signal region. The Bayesian Neural Networks(BNN) are applied
to separate neutrino events from backgrounds in reactor neutrino experiments.
As a result, the most neutrino events and uncorrelated background events in the
signal region can be identified with BNN, and the part events each of the fast
neutron and He/Li backgrounds in the signal region can be
identified with BNN. Then, the signal to noise ratio in the signal region is
enhanced with BNN. The neutrino discrimination increases with the increase of
the neutrino rate in the training sample. However, the background
discriminations decrease with the decrease of the background rate in the
training sample.Comment: 9 pages, 1 figures, 1 tabl
Improving Application of Bayesian Neural Networks to Discriminate Neutrino Events from Backgrounds in Reactor Neutrino Experiments
The application of Bayesian Neural Networks(BNN) to discriminate neutrino
events from backgrounds in reactor neutrino experiments has been described in
Ref.\cite{key-1}. In the paper, BNN are also used to identify neutrino events
in reactor neutrino experiments, but the numbers of photoelectrons received by
PMTs are used as inputs to BNN in the paper, not the reconstructed energy and
position of events. The samples of neutrino events and three major backgrounds
from the Monte-Carlo simulation of a toy detector are generated in the signal
region. Compared to the BNN method in Ref.\cite{key-1}, more He/Li
background and uncorrelated background in the signal region can be rejected by
the BNN method in the paper, but more fast neutron background events in the
signal region are unidentified using the BNN method in the paper. The
uncorrelated background to signal ratio and the He/Li background to
signal ratio are significantly improved using the BNN method in the paper in
comparison with the BNN method in Ref.\cite{key-1}. But the fast neutron
background to signal ratio in the signal region is a bit larger than the one in
Ref.\cite{key-1}.Comment: 9 pages, 1 figure and 1 table, accepted by Journal of Instrumentatio
Bifurcations in annular electroconvection with an imposed shear
We report an experimental study of the primary bifurcation in
electrically-driven convection in a freely suspended film. A weakly conducting,
submicron thick smectic liquid crystal film was supported by concentric
circular electrodes. It electroconvected when a sufficiently large voltage
was applied between its inner and outer edges. The film could sustain rapid
flows and yet remain strictly two-dimensional. By rotation of the inner
electrode, a circular Couette shear could be independently imposed. The control
parameters were a dimensionless number , analogous to the Rayleigh
number, which is and the Reynolds number of the
azimuthal shear flow. The geometrical and material properties of the film were
characterized by the radius ratio , and a Prandtl-like number . Using measurements of current-voltage characteristics of a large number of
films, we examined the onset of electroconvection over a broad range of
, and . We compared this data quantitatively to
the results of linear stability theory. This could be done with essentially no
adjustable parameters. The current-voltage data above onset were then used to
infer the amplitude of electroconvection in the weakly nonlinear regime by
fitting them to a steady-state amplitude equation of the Landau form. We show
how the primary bifurcation can be tuned between supercritical and subcritical
by changing and .Comment: 17 pages, 12 figures. Submitted to Phys. Rev. E. Minor changes after
refereeing. See also http://mobydick.physics.utoronto.c
Intelligent Models to Predict the Prognosis of Premature Neonates According to Their EEG Signals
The aim of this paper is to find the best intelligent model that allows predicting the future of premature newborns according to their electroencephalogram (EEG). EEG is a signal that measures the electrical activity of the brain. In this paper, the authors used a dataset of 397 EEG records detected at birth of premature newborns and their classification by doctors two years later: normal, sick or risky. They executed machine learning on this dataset using several intelligent models such as multiple linear regression, linear discriminant analysis, artificial neural network and decision tree. They used 14 parameters concerning characteristics extracted from EEG records that affect the prognosis of the newborn. Then, they presented a complete comparative study between these models in order to find who gives best results. Finally, they found that decision tree gave best result with performance of 100% for sick records, 76.9% for risky and 69.1% for normal ones
First hint for CP violation in neutrino oscillations from upcoming superbeam and reactor experiments
We compare the physics potential of the upcoming neutrino oscillation
experiments Daya Bay, Double Chooz, NOvA, RENO, and T2K based on their
anticipated nominal luminosities and schedules. After discussing the
sensitivity to theta_{13} and the leading atmospheric parameters, we
demonstrate that leptonic CP violation will hardly be measurable without
upgrades of the T2K and NOvA proton drivers, even if theta_{13} is large. In
the presence of the proton drivers, the fast track to hints for CP violation
requires communication between the T2K and NOvA collaborations in terms of a
mutual synchronization of their neutrino-antineutrino run plans. Even in that
case, upgrades will only discover CP violation in a relatively small part of
the parameter space at the 3 sigma confidence level, while 90% confidence level
hints will most likely be obtained. Therefore, we conclude that a new facility
will be required if the goal is to obtain a significant result with high
probability.Comment: 27 pages, 12 figure
Electroconvection in a Suspended Fluid Film: A Linear Stability Analysis
A suspended fluid film with two free surfaces convects when a sufficiently
large voltage is applied across it. We present a linear stability analysis for
this system. The forces driving convection are due to the interaction of the
applied electric field with space charge which develops near the free surfaces.
Our analysis is similar to that for the two-dimensional B\'enard problem, but
with important differences due to coupling between the charge distribution and
the field. We find the neutral stability boundary of a dimensionless control
parameter as a function of the dimensionless wave number .
, which is proportional to the square of the applied voltage, is
analogous to the Rayleigh number. The critical values and
are found from the minimum of the stability boundary, and its
curvature at the minimum gives the correlation length . The
characteristic time scale , which depends on a second dimensionless
parameter , analogous to the Prandtl number, is determined from the
linear growth rate near onset. and are coefficients in the
Ginzburg-Landau amplitude equation which describes the flow pattern near onset
in this system. We compare our results to recent experiments.Comment: 36 pages, 7 included eps figures, submitted to Phys Rev E. For more
info, see http://mobydick.physics.utoronto.ca
Shear instabilities of freely standing thermotropic smectic-A films
In this Letter we discuss theoretically the instabilities of thermotropic
freely standing smectic-A films under shear flow\cite{re:wu}. We show that, in
Couette geometry, the centrifugal force pushes the liquid crystal toward the
outer boundary and induces smectic layer dilation close to the outer boundary.
Under strong shear, this effect induces a layer buckling instability. The
critical shear rate is proportional to , where is the thickness
of the film.Comment: 12 pages, 2 figure
Common Origin of Soft mu-tau and CP Breaking in Neutrino Seesaw and the Origin of Matter
Neutrino oscillation data strongly support mu-tau symmetry as a good
approximate flavor symmetry of the neutrino sector, which has to appear in any
viable theory for neutrino mass-generation. The mu-tau breaking is not only
small, but also the source of Dirac CP-violation. We conjecture that both
discrete mu-tau and CP symmetries are fundamental symmetries of the seesaw
Lagrangian (respected by interaction terms), and they are only softly broken,
arising from a common origin via a unique dimension-3 Majorana mass-term of the
heavy right-handed neutrinos. From this conceptually attractive and simple
construction, we can predict the soft mu-tau breaking at low energies, leading
to quantitative correlations between the apparently two small deviations
\theta_{23} - 45^o and \theta_{13} - 0^o. This nontrivially connects the
on-going measurements of mixing angle \theta_{23} with the upcoming
experimental probes of \theta_{13}. We find that any deviation of \theta_{23} -
45^o must put a lower limit on \theta_{13}. Furthermore, we deduce the low
energy Dirac and Majorana CP violations from a common soft-breaking phase
associated with mu-tau breaking in the neutrino seesaw. Finally, from the soft
CP breaking in neutrino seesaw we derive the cosmological CP violation for the
baryon asymmetry via leptogenesis. We fully reconstruct the leptogenesis
CP-asymmetry from the low energy Dirac CP phase and establish a direct link
between the cosmological CP-violation and the low energy Jarlskog invariant. We
predict new lower and upper bounds on the \theta_{13} mixing angle, 1^o <
\theta_{13} < 6^o. In addition, we reveal a new hidden symmetry that dictates
the solar mixing angle \theta_12 by its group-parameter, and includes the
conventional tri-bimaximal mixing as a special case, allowing deviations from
it.Comment: 60pp, JCAP in Press, v2: only minor stylistic refinements (added Daya
Bay's future sensitivity in Figs.2+8, shortened some eqs, added new
Appendix-A and some references), comments are welcome
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