Full-Disk Chromospheric Vector Magnetograms with Ca II 854.2 nm line: Some Promising Applications
Gosain, Sanjay; Harvey, J. W.; Harker, Brian; Pillet, V. M.; Pevtsov, Alexei A.; Marble, Andrew R.; Bertello, Luca; + SOLIS-Team
2016-05-01
Over the last decade, the focus of solar magnetometry has shifted outward from the photosphere to the chromospheric layers. The reasons for this are many. With regards to instrumentation faster detectors with more sensitivity have become available, as have fast electro-optic modulators. Also, there are several potential benefits of observing vector fields in the chromospheric layer as the magnetic field is more force-free in this layer as compared to the photosphere. Coronal force-free field extrapolations are more reliable using chromospheric fields as the lower boundary condition and free magnetic energy is readily computed using the magnetic virial theorem. Recently, a full Stokes polarimeter for the chromospheric Ca II 854.2 nm spectral line was developed and installed in the Vector Spectromagnetograph (VSM) instrument on the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope. We present details of this new polarimeter, full disk spectropolarimetric observations and vector magnetograms of the chromosphere, and examples of some promising applications (e.g., maps of normal component of electric current density in the chromosphere, free magnetic energy estimated using virial theorem, and non-potentiality parameter magnetic shear angle).This work utilizes SOLIS data obtained by the NSO Integrated Synoptic Program (NISP), managed by the National Solar Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation
Mi Gauss es su Gauss: Lessons from Cross-Calibrating 40 years of Full Disk Magnetograms
Werginz, Zachary; Munoz-Jaramillo, Andres; Martens, Petrus C.; Harvey, J. W.
2017-08-01
Full-disk line-of-sight magnetograms from the Kitt Peak Vacuum Telescope (KPVT) are a highly valuable, but underutilized, source of data for understanding long-term solar variability. Here we present the results of a project for obtaining a cross-callibrated series of magnetograms spanning 40 years including KPVT (512 and SPMG), SOHO/MDI and SDO/HMI magnetographs. The biggest challenge we face is empirically identifying a calibration factor and estimate of uncertainty between instruments with little temporal overlap.Here we propose a method that fragments magnetograms into spherical quadrangles bounded by latitudes and longitudes and calculates various information such as total area, mean flux density, and distance from disk center. Our main assumption is that the Sun does not change significantly over daily time periods.First a magnetogram to be calibrated is differentially rotated to match a reference magnetogram in time. Then the smaller magnetogram is interpolated into the larger one to account for sub-pixel heliographic coordinates. We then produce equally spaced bands of latitude and longitude determined from a fragmentation parameter. These are used to map out regions on each magnetogram that are expected to relay the same information. Our efforts to cross-calibrate lead to results that vary with fragmentation parameters, the difference in time of selected magnetograms, and distance from disk center.Given that this cross-callibrated series will be made publically available, we are looking for constructive criticism, suggestions, and feedback. Please join us in making these data as good as they can be.
Full-disk nonlinear force-free field extrapolation of SDO/HMI and SOLIS/VSM magnetograms
Tadesse, T.; Wiegelmann, T.; Inhester, B.; MacNeice, P.; Pevtsov, A.; Sun, X.
2013-02-01
Context. The magnetic field configuration is essential for understanding solar explosive phenomena, such as flares and coronal mass ejections. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Two complications of this approach are that the measured photospheric magnetic field is not force-free and that one has to apply a preprocessing routine to achieve boundary conditions suitable for the force-free modeling. Furthermore the nonlinear force-free extrapolation code should take uncertainties into account in the photospheric field data. They occur due to noise, incomplete inversions, or azimuth ambiguity-removing techniques. Aims: Extrapolation codes in Cartesian geometry for modeling the magnetic field in the corona do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, e.g., a single active region. Here we apply a method for nonlinear force-free coronal magnetic field modeling and preprocessing of photospheric vector magnetograms in spherical geometry using the optimization procedure to full disk vector magnetograms. We compare the analysis of the photospheric magnetic field and subsequent force-free modeling based on full-disk vector maps from Helioseismic and Magnetic Imager (HMI) onboard the solar dynamics observatory (SDO) and Vector Spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS). Methods: We used HMI and VSM photospheric magnetic field measurements to model the force-free coronal field above multiple solar active regions, assuming magnetic forces to dominate. We solved the nonlinear force-free field equations by minimizing a functional in spherical coordinates over a full disk and excluding the poles. After searching for the optimum modeling parameters for the particular data sets, we compared the resulting nonlinear force-free model fields. We compared
Forecasting Coronal Mass Ejections from Vector Magnetograms
Falconer, D. A.; Moore, R. L.; Gary, G. A.; Six, N. Frank (Technical Monitor)
2002-01-01
In a 17 vector magnetogram study of 12 bipolar active regions (Falconer, Moore, & Gary, 2002, ApJ in press), we correlated four quantitative global magnetic measures with the Coronal Mass Ejections (CME) productivity of the active region. The global measures included a measure of active region size, the total magnetic flux phi and three measures of an active region global nonpotentiality 1) the net current (I (sub N)), 2) the length of the strong-shear, strong-field main neutral line (L(sub SS)) and 3) and the normalized twist (alpha = muIN/PHI). The CME productivity was determined from YOHKOH/SXT observations, Geostationary Operational Environmental Satellite (GOES), and when possible Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment (SOHO/LASCO) observations within 12 days of the day of the magnetogram. We found that the three measures of global nonpotentiality (I(sub N), L(sub SS), alpha) were all well correlated (greater than 99% confidence level) with an active region's CME productivity. The sample size was to small to confirm if there was a statistical significant correlation of the globally nonscientist measures with future CME activity (i.e. from the date of the magnetogram forward). We are doubling our sample, and will report on the statistical significance of global nonpotentiality as a predictor of future CME productivity. The new active regions are all from the first year of the upgraded MSFC vector magnetograms. This work, is funded by NSF through the Space Weather Program, by NASA through the Living with the Star, Targeted Research and Technology, and by NASA Solar Physics Supporting Research and Technology Program. The upgrade to the MSFC vector magnetograph was supported by the High Energy Solar Spectroscopic Imager (HESSI) mission.
Study of solar active regions based on BOAO vector magnetograms
Moon, Y J; Yun, H S; Cho, E A
1999-01-01
In this study we present the study of solar active regions based on BOAO vector magnetograms and $H\\alpha$ filtergrams. With the new calibration method we analyzed BOAO vector magnetograms taken from the SOFT observational system to compare with those of other observing systems. In this study it has been demonstrated that (1) our longitudinal magnetogram matches very well the corresponding Mitaka's magnetogram to the extent that the maximum correlation yields r=0.962 between our re-scaled longitudinal magnetogram and the Mitaka's magnetogram; (2) according to a comparison of our magnetograms of AR 8422 with those taken at Mitaka solar observatory their longitudinal fields are very similar to each other while transverse fields are a little different possibly due to large noise level; (3) main features seen by our longitudinal magnetograms of AR 8422 and AR 8419 and the corresponding Kitt Peak magnetograms are very similar to each other; (4) time series of our vector magnetograms and H-alpha observations of AR ...
Nishizuka, N; Kubo, Y; Den, M; Watari, S; Ishii, M
2016-01-01
We developed a flare prediction model using machine learning, which is optimized to predict the maximum class of flares occurring in the following 24 h. Machine learning is used to devise algorithms that can learn from and make decisions on a huge amount of data. We used solar observation data during the period 2010-2015, such as vector magnetogram, ultraviolet (UV) emission, and soft X-ray emission taken by the Solar Dynamics Observatory and the Geostationary Operational Environmental Satellite. We detected active regions from the full-disk magnetogram, from which 60 features were extracted with their time differentials, including magnetic neutral lines, the current helicity, the UV brightening, and the flare history. After standardizing the feature database, we fully shuffled and randomly separated it into two for training and testing. To investigate which algorithm is best for flare prediction, we compared three machine learning algorithms: the support vector machine (SVM), k-nearest neighbors (k-NN), and ...
Projection Effects on Physical Parameters Obtained from Solar Vector Magnetograms
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Projection effects in Huairou solar vector magnetograms are corrected by transferring or mapping the observed vector magnetogram in the image plane to the heliographic plane (planar correction) and to the heliospheric coordinate system (spherical correction). The magnetograms after the correction are considerably different. The planar correction and the spherical correction lead to slightly different magnetic configurations, especially when the active region involved is far from the disk center. We also discuss the effects of the corrections on magnetic activity parameters, such as magnetic shear, current helicity, etc. It is shown that the neutral line is obviously distorted after the mapping. The mapping generally decreases the average shear angle on the neutral line by several degrees when the active region is in the eastern hemisphere, and increases it when in the western hemisphere. In most of the cases studied, the correction reduces the current helicity imbalance, and sometimes even changes its sign. It is found that the current helicity imbalance may change its sign in its evolution when there are apparent fluxes emerging from the lower photosphere. The corrections increase the noise level of Bz greatly, and decrease the noise level of Bt slightly. The accuracy of the magnetic field measurement at Huairou is estimated to be better than 20 G and 150 G for the longitudinal and the transverse component, respectively.
Tracking Vector Magnetograms with the Magnetic Induction Equation
Schuck, P W
2008-01-01
The differential affine velocity estimator (DAVE) developed in Schuck (2006) for estimating velocities from line-of-sight magnetograms is modified to directly incorporate horizontal magnetic fields to produce a differential affine velocity estimator for vector magnetograms (DAVE4VM). The DAVE4VM's performance is demonstrated on the synthetic data from the anelastic pseudospectral ANMHD simulations that were used in the recent comparison of velocity inversion techniques by Welsch (2007). The DAVE4VM predicts roughly 95% of the helicity rate and 75% of the power transmitted through the simulation slice. Inter-comparison between DAVE4VM and DAVE and further analysis of the DAVE method demonstrates that line-of-sight tracking methods capture the shearing motion of magnetic footpoints but are insensitive to flux emergence -- the velocities determined from line-of-sight methods are more consistent with horizontal plasma velocities than with flux transport velocities. These results suggest that previous studies that...
Nishizuka, N.; Sugiura, K.; Kubo, Y.; Den, M.; Watari, S.; Ishii, M.
2017-02-01
We developed a flare prediction model using machine learning, which is optimized to predict the maximum class of flares occurring in the following 24 hr. Machine learning is used to devise algorithms that can learn from and make decisions on a huge amount of data. We used solar observation data during the period 2010–2015, such as vector magnetograms, ultraviolet (UV) emission, and soft X-ray emission taken by the Solar Dynamics Observatory and the Geostationary Operational Environmental Satellite. We detected active regions (ARs) from the full-disk magnetogram, from which ∼60 features were extracted with their time differentials, including magnetic neutral lines, the current helicity, the UV brightening, and the flare history. After standardizing the feature database, we fully shuffled and randomly separated it into two for training and testing. To investigate which algorithm is best for flare prediction, we compared three machine-learning algorithms: the support vector machine, k-nearest neighbors (k-NN), and extremely randomized trees. The prediction score, the true skill statistic, was higher than 0.9 with a fully shuffled data set, which is higher than that for human forecasts. It was found that k-NN has the highest performance among the three algorithms. The ranking of the feature importance showed that previous flare activity is most effective, followed by the length of magnetic neutral lines, the unsigned magnetic flux, the area of UV brightening, and the time differentials of features over 24 hr, all of which are strongly correlated with the flux emergence dynamics in an AR.
Petrie, Gordon
2017-01-01
The Sun's polar fields play a leading role in structuring the large-scale solar atmosphere and in determining the interplanetary magnetic field. They are also believed to supply the seed field for the subsequent solar activity cycle. However, present-day synoptic observations do not have sufficient spatial resolution or sensitivity to diagnose accurately the high-latitude magnetic vector field. The high spatial resolution and sensitivity of the full-Stokes observations from the Hinode Solar Optical Telescope Spectro-Polarimeter, observing the poles long-term, allows us to build up a detailed picture of the Cycle 24 polar field reversal, including the changing latitude distribution of the high-latitude flux, and to study the effect on global coronal field models. The Hinode observations provide detailed information on the dominant facular-scale magnetic structure of the polar fields, and their field inclination and flux distribution. Hybrid synoptic magnetograms are constructed from Hinode polar measurements and full-disk magnetograms from the Synoptic Optical Long-term Investigations of the Sun (SOLIS) Vector Spectro-Magnetograph (VSM), and coronal potential field models are calculated. Loss of effective spatial resolution at the highest latitudes presents complications. Possible improvements to synoptic polar data are discussed.
Wang, A. H.; Wu, S. T.; Liu, Yang; Hathaway, D.
2008-01-01
We introduce a numerical simulation method for recovering the photospheric velocity field from the vector magnetograms. The traditional method is local correlation tracking (LCT) which is based on measuring the relative displacements of features in blocks of pixels between successive white-light images or magnetograms. Within this method, there are a variety of implementations. One of recently developed implementations is induction local correlation tracking (ILCT) as described by Welsch et al. (2004). They employ the normal component of magnetic induction equation as a constraint to assure consistent solutions. Our numerical method uses the fully three-dimensional MHD equations to recover the photospheric velocity field with individual vector magnetograms. We compare our method to the ILCT method using NOAA AR8210 as an example. The differences and similarities are discussed in detail.
On resolving the 180 deg ambiguity for a temporal sequence of vector magnetograms
Cheung, M. C.
2008-05-01
The solar coronal magnetic field evolves in response to the underlying photospheric driving. To study this connection by means of data-driven modeling, an accurate knowledge of the evolution of the photospheric vector field is essential. While there is a large body of work on attempts to resolve the 180 deg ambiguity in the component of the magnetic field transverse to the line of sight, most of these methods are applicable only to individual frames. With the imminent launch of the Solar Dynamics Observatory, it is especially timely for us to develop possible automated methods to resolve the ambiguity for temporal sequences of magnetograms. We present here the temporal acute angle method, which makes use of preceding disambiguated magnetograms as reference solutions for resolving the ambiguity in subsequent frames. To find the strengths and weaknesses of this method, we have carried out tests (1) on idealized magnetogram sequences involving simple rotating, shearing and straining flows and (2) on a synthetic magnetogram sequence from a 3D radiative MHD simulation of an buoyant magnetic flux tube emerging through granular convection. A metric for automatically picking out regions where the method is likely to fail is also presented.
Deriving Potential Coronal Magnetic Fields from Vector Magnetograms
Welsch, Brian T.; Fisher, George H.
2016-08-01
The minimum-energy configuration for the magnetic field above the solar photosphere is curl-free (hence, by Ampère's law, also current-free), so can be represented as the gradient of a scalar potential. Since magnetic fields are divergence free, this scalar potential obeys Laplace's equation, given an appropriate boundary condition (BC). With measurements of the full magnetic vector at the photosphere, it is possible to employ either Neumann or Dirichlet BCs there. Historically, the Neumann BC was used with available line-of-sight magnetic field measurements, which approximate the radial field needed for the Neumann BC. Since each BC fully determines the 3D vector magnetic field, either choice will, in general, be inconsistent with some aspect of the observed field on the boundary, due to the presence of both currents and noise in the observed field. We present a method to combine solutions from both Dirichlet and Neumann BCs to determine a hybrid, "least-squares" potential field, which minimizes the integrated square of the residual between the potential and actual fields. We also explore weighting the residuals in the fit by spatially uniform measurement uncertainties. This has advantages both in not overfitting the radial field used for the Neumann BC, and in maximizing consistency with the observations. We demonstrate our methods with SDO/HMI vector magnetic field observations of active region 11158, and find that residual discrepancies between the observed and potential fields are significant, and they are consistent with nonzero horizontal photospheric currents. We also analyze potential fields for two other active regions observed with two different vector magnetographs, and find that hybrid-potential fields have significantly less energy than the Neumann fields in every case - by more than 10^{32} erg in some cases. This has major implications for estimates of free magnetic energy in coronal field models, e.g., non-linear force-free field extrapolations.
Probabilistic forecasting of solar flares from vector magnetogram data
Barnes, G.; Leka, K. D.; Schumer, E. A.; Della-Rose, D. J.
2007-09-01
Discriminant analysis is a statistical approach for assigning a measurement to one of several mutually exclusive groups. Presented here is an application of the approach to solar flare forecasting, adapted to provide the probability that a measurement belongs to either group, the groups in this case being solar active regions which produced a flare within 24 hours and those that remained flare quiet. The technique is demonstrated for a large database of vector magnetic field measurements obtained by the University of Hawai'i Imaging Vector Magnetograph. For a large combination of variables characterizing the photospheric magnetic field, the results are compared to a Bayesian approach for solar flare prediction, and to the method employed by the U.S. Space Environment Center (SEC). Although quantitative comparison is difficult as the present application provides active region (rather than whole-Sun) forecasts, and the present database covers only part of one solar cycle, the performance of the method appears comparable to the other approaches.
Calibration of Vector Magnetogram with the Nonlinear Least-squares Fitting Technique
Institute of Scientific and Technical Information of China (English)
Jiang-Tao Su; Hong-Qi Zhang
2004-01-01
To acquire Stokes profiles from observations of a simple sunspot with the Video Vector Magnetograph at Huairou Solar Observing Station(HSOS),we scanned the FeIλ5324.19 A line over the wavelength interval from 150mA redward of the line center to 150mA blueward,in steps of 10mA.With the technique of analytic inversion of Stokes profiles via nonlinear least-squares,we present the calibration coefficients for the HSOS vector magnetic magnetogram.We obtained the theoretical calibration error with linear expressions derived from the Unno-Becker equation under weak-field approximation.
Prediction of Coronal Mass Ejections From Vector Magnetograms: Quantitative Measures as Predictors
Falconer, D. A.; Moore, R. L.; Gary, G. A.; Rose, M. Franklin (Technical Monitor)
2001-01-01
We derived two quantitative measures of an active region's global nonpotentiality from the region's vector magnetogram, 1) the net current (I(sub N)), and 2) the length of strong-shear, strong-field main neutral line (Lss), and used these two measures in a pilot study of the CME productivity of 4 active regions. We compared the global nonpotentiality measures to the active regions' CME productivity determined from GOES and Yohkoh/SXT observations. We found that two of the active regions were highly globally nonpotential and were CME productive, while the other two active regions had little global nonpotentiality and produced no CMEs. At the Fall 2000 AGU, we reported on an expanded study (12 active regions and 17 magnetograms) in which we evaluated four quantitative global measures of an active region's magnetic field and compared these measures with the CME productivity. The four global measures (all derived from MSFC vector magnetograms) included our two previous measures (I(sub N) and L(sub ss)) as well as two new ones, the total magnetic flux (PHI) (a measure of an active region's size), and the normalized twist (alpha (bar)= muIN/PHI). We found that the three quantitative measures of global nonpotentiality (I(sub N), L(sub ss), alpha (bar)) were all well correlated (greater than 99% confidence level) with an active region's CME productivity within plus or minus 2 days of the day of the magnetogram. We will now report on our findings of how good our quantitative measures are as predictors of active-region CME productivity, using only CMEs that occurred after the magnetogram. We report the preliminary skill test of these quantitative measures as predictors. We compare the CME prediction success of our quantitative measures to the CME prediction success based on an active region's past CME productivity. We examine the cases of the handful of false positive and false negatives to look for improvements to our predictors. This work is funded by NSF through the Space
Wiegelmann, T; Inhester, B; Tadesse, T; Sun, X; Hoeksema, J T
2012-01-01
The SDO/HMI instruments provide photospheric vector magnetograms with a high spatial and temporal resolution. Our intention is to model the coronal magnetic field above active regions with the help of a nonlinear force-free extrapolation code. Our code is based on an optimization principle and has been tested extensively with semi-analytic and numeric equilibria and been applied before to vector magnetograms from Hinode and ground based observations. Recently we implemented a new version which takes measurement errors in photospheric vector magnetograms into account. Photospheric field measurements are often due to measurement errors and finite nonmagnetic forces inconsistent as a boundary for a force-free field in the corona. In order to deal with these uncertainties, we developed two improvements: 1.) Preprocessing of the surface measurements in order to make them compatible with a force-free field 2.) The new code keeps a balance between the force-free constraint and deviation from the photospheric field m...
Crouch, A.; Barnes, G.
2008-01-01
We demonstrate that the azimuthal ambiguity that is present in solar vector magnetogram data can be resolved with line-of-sight and horizontal heliographic derivative information by using the divergence-free property of magnetic fields without additional assumptions. We discuss the specific derivative information that is sufficient to resolve the ambiguity away from disk center, with particular emphasis on the line-of-sight derivative of the various components of the magnetic field. Conversely, we also show cases where ambiguity resolution fails because sufficient line-of-sight derivative information is not available. For example, knowledge of only the line-of-sight derivative of the line-of-sight component of the field is not sufficient to resolve the ambiguity away from disk center.
Falconer, David; Tiwari, Sanjiv K.; Moore, Ronald L.; Khazanov, Igor
2017-08-01
Projection error limits the use of vector magnetograms of active regions (ARs) far from disk center. For ARs observed up to 60o from disk center, we demonstrate a method of measuring and reducing the projection error in the magnitude of any whole-AR parameter derived from a vector magnetogram that has been deprojected to disk center. The method assumes that the center-to-limb curve of the average of the parameter’s absolute values measured from the disk passage of a large number of ARs and normalized to each AR’s absolute value of the parameter at central meridian, gives the average fractional projection error at each radial distance from disk center. To demonstrate the method, we use a large set of large-flux ARs and apply the method to a whole-AR parameter that is among the simplest to measure: whole-AR magnetic flux. We measure 30,845 SDO/HMI vector magnetograms covering the disk passage of 272 large-flux ARs, each having whole-AR flux >1022 Mx. We obtain the center-to-limb radial-distance run of the average projection error in measured whole-AR flux from a Chebyshev fit to the radial-distance plot of the 30,845 normalized measured values. The average projection error in the measured whole-AR flux of an AR at a given radial distance is removed by multiplying the measured flux by the correction factor given by the fit. The correction is important for both the study of evolution of ARs and for improving the accuracy of forecasting an AR’s major flare/CME productivity. We will also show corrections for other whole-AR parameters, especially AR free-energy proxies.
Crouch, Ashley D
2015-01-01
We continue the investigation of how to use the divergence-free condition to resolve the azimuthal ambiguity present in vector magnetogram data. In previous articles, by Crouch, Barnes, and Leka (Solar Physics, 260, 271, 2009) and Crouch (Solar Physics, 282, 107, 2013), all methods used an expression for the divergence of the magnetic field that involves differentiation of quantities that depend on the choice of azimuthal angle. As a result, all heights used to approximate line-of-sight derivatives should generally be disambiguated simultaneously. In this article, we investigate a set of methods that use an expression for the divergence that involves differentiation of quantities that do not depend on the choice of azimuthal angle. This results in an expression for the divergence that can be used to disambiguate each height independently. We test two methods using synthetic and find that the two-step, hybrid method, adapted to disambiguate each height independently, generally produces reasonable results. More...
Sun, Xudong; Hoeksema, Jon Todd; Liu, Yang; Kazachenko, Maria D.; Chen, Ruizhu
2017-08-01
The solar active region photospheric magnetic field evolves rapidly during major eruptive events, suggesting appreciable feedback from the corona. Previous studies of these “magnetic imprints” are mostly based on line-of-sight only or lower-cadence vector observations; a temporally resolved depiction of the vector field evolution is hitherto lacking. Here, we introduce the high-cadence (90 s or 135 s) vector magnetogram data set from the Helioseismic and Magnetic Imager, which is well suited for investigating the phenomenon. These observations allow quantitative characterization of the permanent, step-like changes that are most pronounced in the horizontal field component (Bh). A highly structured pattern emerges from analysis of several events, including an archetypical example, SOL2011-02-15T01:56, where Bh near the main polarity inversion line increases significantly during the earlier phase of the associated flare with a timescale of several minutes, while Bh in the periphery decreases at later times with smaller magnitudes and a slightly longer timescale. The data set also allows effective identification of the “magnetic transient” artifact, where enhanced flare emission alters the Stokes profiles and the inferred magnetic field becomes unreliable. Our results provide insights on the momentum processes in solar eruptions. The data set may also be useful to the study of sunquakes and data-driven modeling of the corona.
Software for Interactively Visualizing Solar Vector Magnetograms of Udaipur Solar Observatory
Indian Academy of Sciences (India)
Sanjay Gosain; Sanjiv Tiwari; Jayant Joshi; P. Venkatakrishnan
2008-03-01
The Solar Vector Magnetograph (SVM) at Udaipur Solar Observatory saw its first light in April 2005. The retrieval of vector fields from the imaging spectro-polarimetric observational data requires a substantial amount of computer post-processing. The GUI-based data reduction and analysis software have been developed to make the data processing pipeline user-friendly and less time-consuming. In this paper we describe these software packages.
Tadesse, Tilaye; Gosain, S; MacNeice, P; Pevtsov, Alexei A
2013-01-01
The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Currently there are several modelling techniques being used to calculate three-dimension of the field lines into the solar atmosphere. For the first time, synoptic maps of photospheric vector magnetic field synthesized from Vector Spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) are used to model the coronal magnetic field and estimate free magnetic energy in the global scale. The free energy (i.e., the energy in excess of the potential field energy) is one of the main indicators used in space weather forecasts to predict the eruptivity of active regions. We solve the nonlinear force-free field equations using optimizatio...
Tadesse, Tilaye; Wiegelmann, T.; Gosain, S.; Macneice, P.; Pevtsov, Alexei A.
2013-01-01
The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Currently there are several modelling techniques being used to calculate three-dimension of the field lines into the solar atmosphere. For the ...
Kazachenko, Maria; Fisher, George; Welsch, Brian
Quantitative studies of the flow of magnetic energy through the solar photosphere require a knowledge of the magnetic field vector B - and knowledge of the electric field E as well. We have modified and improved the technique Fisher et al. developed in 2012, which combines a poloidal-toroidal decomposition (PTD) to determine contributions to E from Faraday's law, with additional non-inductive contributions arising from flux emergence near polarity inversion lines, determined from Doppler measurements. The new technique, which we call the ``PTD Doppler FLCT Ideal'' (or PDFI) technique, incorporates Doppler information from non-normal viewing angles, and adopts the faster and more robust FISHPACK software for solutions of the two-dimensional Poisson equations. We demonstrate the performance using synthetic data from the anelastic pseudo-spectral ANMHD simulations that were used in the recent comparison of velocity inversion techniques (Welsch et al. 2007) and the PTD inversion (Fisher et al. 2012). We find that the PDFI method has roughly 10% reconstruction errors (it predicts roughly 100% of the photospheric Poynting flux and 110% of the helicity flux rate at normal viewing angles, consistent with Fisher et al. (2012) results, and 90% of Poynting flux and 110% helicity flux at theta=30 degrees). We conclude that the PDFI method can be routinely applied to observed magnetic field data and, as an example, apply it to the 6-day HMI/SDO vector magnetogram sequence centered at AR11158, where an X2.2 flare occurred. We discuss how our electric field maps are used to drive coronal magnetic field with a global evolutionary model, or CGEM, a collaborative effort from the UC Berkeley Space Sciences Laboratory (SSL), Stanford University, and Lockheed-Martin.
Tadesse, T.; Wiegelmann, T.; Gosain, S.; MacNeice, P.; Pevtsov, A. A.
2014-01-01
Context. The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Currently, there are several modelling techniques being used to calculate three-dimensional field lines into the solar atmosphere. Aims. For the first time, synoptic maps of a photospheric-vector magnetic field synthesized from the vector spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) are used to model the coronal magnetic field and estimate free magnetic energy in the global scale. The free energy (i.e., the energy in excess of the potential field energy) is one of the main indicators used in space weather forecasts to predict the eruptivity of active regions. Methods. We solve the nonlinear force-free field equations using an optimization principle in spherical geometry. The resulting threedimensional magnetic fields are used to estimate the magnetic free energy content E(sub free) = E(sub nlfff) - E(sub pot), which is the difference of the magnetic energies between the nonpotential field and the potential field in the global solar corona. For comparison, we overlay the extrapolated magnetic field lines with the extreme ultraviolet (EUV) observations by the atmospheric imaging assembly (AIA) on board the Solar Dynamics Observatory (SDO). Results. For a single Carrington rotation 2121, we find that the global nonlinear force-free field (NLFFF) magnetic energy density is 10.3% higher than the potential one. Most of this free energy is located in active regions.
Global Twist of Sunspot Magnetic Fields Obtained from High Resolution Vector Magnetograms
Tiwari, Sanjiv Kumar; Sankarasubramanian, K
2009-01-01
The presence of fine structures in the sunspot vector magnetic fields has been confirmed from Hinode as well as other earlier observations. We studied 43 sunspots based on the data sets taken from ASP/DLSP, Hinode (SOT/SP) and SVM (USO). In this \\emph{Letter}, (i) We introduce the concept of signed shear angle (SSA) for sunspots and establish its importance for non force-free fields. (ii) We find that the sign of global $\\alpha$ (force-free parameter) is well correlated with the global SSA and the photospheric chirality of sunspots. (iii) Local $\\alpha$ patches of opposite signs are present in the umbra of each sunspot. The amplitude of the spatial variation of local $\\alpha$ in the umbra is typically of the order of the global $\\alpha$ of the sunspot. (iv) We find that the local $\\alpha$ is distributed as alternately positive and negative filaments in the penumbra. The amplitude of azimuthal variation of the local $\\alpha$ in the penumbra is approximately an order of magnitude larger than that in the umbra. ...
New observations of the magnetic vector field across the solar disk
Keller, C.U.; Harvey, J.W.; Henney, C.J.
2008-01-01
Full disk solar magnetograms have been available for more than three decades. However, those maps only show the line-of-sight magnetic flux. The physical quantity we really want to know is the magnetic field vector along with the filling factor, i.e. the fractional area of the resolution element tha
Crouch, Ashley D
2012-01-01
We investigate how the azimuthal ambiguity in solar vector magnetogram data can be resolved by using the divergence-free property of magnetic fields. In a previous article, by Crouch, Barnes, and Leka (Solar Phys. 260, 271, 2009), error-free synthetic data were used to test several methods that each make a different assumption about how the divergence-free property can be used to resolve the ambiguity. In this paper this testing is continued with an examination of the effects of Poisson photon noise and limited instrumental spatial resolution. We find that all currently available methods based on the divergence-free property can produce undesirable results when photon noise or unresolved structure are present in the data. We perform a series of experiments aimed at improving the performance of the global minimisation method, which is the most promising of the methods. We present a two-step approach that produces reasonable results in tests using synthetic data. The first step of this approach involves the glo...
Forecasting Space Weather from Magnetograms
Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor
2012-01-01
Large flares and fast CMEs are the drivers of the most severe space weather including Solar Energetic Particle Events (SEP Events). Large flares and their co-produced CMEs are powered by the explosive release of free magnetic energy stored in non-potential magnetic fields of sunspot active regions. The free energy is stored in and released from the low-beta regime of the active region s magnetic field above the photosphere, in the chromosphere and low corona. From our work over the past decade and from similar work of several other groups, it is now well established that (1) a proxy of the free magnetic energy stored above the photosphere can be measured from photospheric magnetograms, maps of the measured field in the photosphere, and (2) an active region s rate of production of major CME/flare eruptions in the coming day or so is strongly correlated with its present measured value of the free-energy proxy. These results have led us to use the large database of SOHO/MDI full-disk magnetograms spanning Solar Cycle 23 to obtain empirical forecasting curves that from an active region s present measured value of the free-energy proxy give the active region s expected rates of production of major flares, CMEs, fast CMEs, and SEP Events in the coming day or so (Falconer et al 2011, Space Weather, 9, S04003). For each type of event, the expected rate is readily converted to the chance that the active region will produce such an event in any given forward time window of a day or so. If the chance is small enough (e.g. <5%), the forecast is All Clear for that type of event. We will present these forecasting curves and demonstrate the accuracy of their forecasts. In addition, we will show that the forecasts for major flares and fast CMEs can be made significantly more accurate by taking into account not only the value of the free energy proxy but also the active region s recent productivity of major flares; specifically, whether the active region has produced a major flare
Tremblay, Benoit; Vincent, Alain
2017-01-01
We present a generalization of the resistive minimum-energy fit (MEF-R: Tremblay and Vincent, Solar Phys. 290, 437, 2015) for non-force-free (NFF) magnetic fields. In MEF-R, an extremum principle is used to infer two-dimensional maps of plasma motions [boldsymbol{v}(x,y)] and magnetic eddy diffusivity [η _{eddy}(x,y)] at the photosphere. These reconstructions could be used as boundary conditions in data-driven simulations or in data assimilation. The algorithm is validated using the analytical model of a resistive expanding spheromak by Rakowski, Laming, and Lyutikov ( Astrophys. J. 730, 30, 2011). We study the flaring Active Region AR 12158 using a series of magnetograms and Dopplergrams provided by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). The results are discussed for a non-force-free magnetic-field reconstruction [boldsymbol{B}_{NFF}] (Hu and Dasgupta in Solar Phys. 247, 87, 2008). We found that the vertical plasma velocities [vz(x,y)] inferred using MEF-R are very similar to the observed Doppler velocities [vr(x,y)]. Finally, we study the potential spatial correlation between microturbulent velocities and significant values of η_{eddy}(x,y).
24-Hour Forecasting of CME/Flare Eruptions from Active-Region Magnetograms (Invited)
Falconer, D. A.; Barghouty, A.; Khazanov, I. G.; Moore, R. L.
2010-12-01
We have developed an automated tool for forecasting severe space weather from full-disk magnetograms. This tool is now being used on a trial basis by NASA’s Space Radiation Analysis Group (SRAG) at JSC. SRAG is responsible for the monitoring and forecasting of exposure the astronauts to particle radiation. The tool is described in Falconer, Barghouty, Khazanov, and Moore (2010), submitted to Space Weather. The new software tool is designed for the empirical forecasting of M- and X-class flares, coronal mass ejections, and solar energetic particle events. For each of these event types, the algorithm is based on the empirical relationship between the event rate and a proxy of the active region’s free magnetic energy. The relationship is determined from ~40,000 active-region magnetograms from ~1,300 active regions that were observed within 30 heliographic degrees from disk center by SOHO/MDI, and that have known histories of flare, coronal mass ejection, and solar energetic particle event production during disk passage. The tool automatically extracts each strong-field magnetic areas from an MDI full-disk magnetogram, identifies each as a NOAA active region, and measures the proxy of the active region’s free magnetic energy from the extracted magnetogram. For each active region, the empirical relationship is then used to convert the free magnetic energy proxy into the active region’s expected event rate (see figure). The expected event rate in turn can be readily converted into the probability that the active region will produce such an event in a given forward time window. We can make this tool applicable to the full-disk line-of-sight magnetograms from SDO/HMI or as a backup, from NSO/GONG. By empirically determining the conversion of the value of free-energy proxy measured from an HMI magnetogram to that which would be measured from an MDI magnetogram, we can use the HMI magnetograms with the empirical relationships determined from our MDI data base to make
SOLAR FLARE PREDICTION USING SDO/HMI VECTOR MAGNETIC FIELD DATA WITH A MACHINE-LEARNING ALGORITHM
Energy Technology Data Exchange (ETDEWEB)
Bobra, M. G.; Couvidat, S., E-mail: couvidat@stanford.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)
2015-01-10
We attempt to forecast M- and X-class solar flares using a machine-learning algorithm, called support vector machine (SVM), and four years of data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager, the first instrument to continuously map the full-disk photospheric vector magnetic field from space. Most flare forecasting efforts described in the literature use either line-of-sight magnetograms or a relatively small number of ground-based vector magnetograms. This is the first time a large data set of vector magnetograms has been used to forecast solar flares. We build a catalog of flaring and non-flaring active regions sampled from a database of 2071 active regions, comprised of 1.5 million active region patches of vector magnetic field data, and characterize each active region by 25 parameters. We then train and test the machine-learning algorithm and we estimate its performances using forecast verification metrics with an emphasis on the true skill statistic (TSS). We obtain relatively high TSS scores and overall predictive abilities. We surmise that this is partly due to fine-tuning the SVM for this purpose and also to an advantageous set of features that can only be calculated from vector magnetic field data. We also apply a feature selection algorithm to determine which of our 25 features are useful for discriminating between flaring and non-flaring active regions and conclude that only a handful are needed for good predictive abilities.
Solar Flare Prediction Using SDO/HMI Vector Magnetic Field Data with a Machine-Learning Algorithm
Bobra, Monica G
2014-01-01
We attempt to forecast M-and X-class solar flares using a machine-learning algorithm, called Support Vector Machine (SVM), and four years of data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager, the first instrument to continuously map the full-disk photospheric vector magnetic field from space. Most flare forecasting efforts described in the literature use either line-of-sight magnetograms or a relatively small number of ground-based vector magnetograms. This is the first time a large dataset of vector magnetograms has been used to forecast solar flares. We build a catalog of flaring and non-flaring active regions sampled from a database of 2,071 active regions, comprised of 1.5 million active region patches of vector magnetic field data, and characterize each active region by 25 parameters. We then train and test the machine-learning algorithm and we estimate its performances using forecast verification metrics with an emphasis on the True Skill Statistic (TSS). We obtain relatively h...
PROMIS series. Volume 8: Midlatitude ground magnetograms
Fairfield, D. H.; Russell, C. T.
1990-01-01
This is the eighth in a series of volumes pertaining to the Polar Region Outer Magnetosphere International Study (PROMIS). This volume contains 24 hour stack plots of 1-minute average, H and D component, ground magnetograms for the period March 10 through June 16, 1986. Nine midlatitude ground stations were selected from the UCLA magnetogram data base that was constructed from all available digitized magnetogram stations. The primary purpose of this publication is to allow users to define universal times and onset longitudes of magnetospheric substorms.
Respiratory Magnetogram Detected with a MEMS Device
Dominguez-Nicolas, Saul M.; Juarez-Aguirre, Raul; Herrera-May, Agustin L.; Garcia-Ramirez, Pedro; Figueras, Eduard; Gutierrez-D., Edmundo A.; Tapia, Jesus A.; Trejo, Argelia; Manjarrez, Elias
2013-01-01
Magnetic fields generated by the brain or the heart are very useful in clinical diagnostics. Therefore, magnetic signals produced by other organs are also of considerable interest. Here we show first evidence that thoracic muscles can produce a strong magnetic flux density during respiratory activity, that we name respiratory magnetogram. We used a small magnetometer based on microelectromechanical systems (MEMS), which was positioned inside the open thoracic cage of anaesthetized and ventilated rats. With this new MEMS sensor of about 20 nT resolution, we recorded a strong and rhythmic respiratory magnetogram of about 600 nT. PMID:24046516
Comparison of Ground- and Space-based Longitudinal Magnetograms
Pietarila, A; Harvey, J W; Pevtsov, A A
2012-01-01
We compare photospheric line-of-sight magnetograms from the Synoptic Long-term Investigations of the Sun (SOLIS) vector spectromagnetograph (VSM) instrument with observations from the 150-foot Solar Tower at Mt. Wilson (MWO), Helioseismic and Magnetic Imager (HMI) on Solar Dynamics Observatory (SDO), and Michelson Doppler Imager (MDI) on Solar and Heliospheric Observatory (SOHO). We find very good agreement between VSM and the other data sources for both disk-averaged flux densities and pixel-by-pixel measurements. We show that the VSM mean flux density time series is of consistently high signal-to-noise with no significant zero-offsets. We discuss in detail some of the factors -spatial resolution, flux dependence and position on the solar disk- affecting the determination of scaling between VSM and SOHO/MDI or SDO/HMI magnetograms. The VSM flux densities agree well with spatially smoothed data from MDI and HMI, although the scaling factors show clear dependence on flux density. The factor to convert VSM to H...
On estimating the force-freeness based on observed magnetograms
Zhang, X M; Su, J T
2016-01-01
It is a common practice in the solar physics community to test whether or not measured photospheric or chromospheric vector magnetograms are force-free, using the Maxwell stress as a measure. Some previous studies have suggested that magnetic fields of active regions in the solar chromosphere are close to be force-free whereas there is no consistency among previous studies on whether magnetic fields of active regions in the solar photosphere are force-free or not. Here we use three kinds of representative magnetic fields (analytical force-free solutions, modeled solar-like force-free fields and observed non-force-free fields) to discuss on how the measurement issues such as limited field of view, instrument sensitivity and measurement error could affect the estimation of force-freeness based on observed magnetograms. Unlike previous studies that focus on discussing the effect of limited field of view or instrument sensitivity, our calculation shows that just measurement error alone can significantly influence...
Solar Flare Prediction Using SDO/HMI Vector Magnetic Field Data with a Machine-Learning Algorithm
Bobra, M.; Couvidat, S. P.
2014-12-01
We attempt to forecast M-and X-class solar flares using a machine-learning algorithm, called Support Vector Machine (SVM), and four years of data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager, the first instrument to continuously map the full-disk photospheric vector magnetic field from space (Schou et al., 2012). Most flare forecasting efforts described in the literature use either line-of-sight magnetograms or a relatively small number of ground-based vector magnetograms. This is the first time such a large dataset of vector magnetograms has been used to forecast solar flares. We build a catalog of flaring and non-flaring active regions sampled from a database of 2,071 active regions, comprised of 1.5 million active region patches of vector magnetic field data, and characterize each active region by 25 parameters --- which include the flux, energy, shear, current, helicity, gradient, geometry, and Lorentz force. We then train and test the machine-learning algorithm. Finally, we estimate the performance of this algorithm using forecast verification metrics with an emphasis on the true skill statistic (TSS). Bloomfield et al. (2012) suggest the use of the TSS as it is not sensitive to the class imbalance problem. Indeed, there are many more non-flaring active regions in a given time interval than flaring ones: this class imbalance distorts many performance metrics and renders comparison between various studies somewhat unreliable. We obtain relatively high TSS scores and overall predictive abilities. We surmise that this is partly due to fine-tuning the SVM for this purpose and also to an advantageous set of features that can only be calculated from vector magnetic field data. We also apply a feature selection algorithm to determine which of our 25 features are useful for discriminating between flaring and non-flaring active regions and conclude that only a handful are needed for good predictive abilities.
Technique for Automated Recognition of Sunspots on Full-Disk Solar Images
Directory of Open Access Journals (Sweden)
Zharkov S
2005-01-01
Full Text Available A new robust technique is presented for automated identification of sunspots on full-disk white-light (WL solar images obtained from SOHO/MDI instrument and Ca II K1 line images from the Meudon Observatory. Edge-detection methods are applied to find sunspot candidates followed by local thresholding using statistical properties of the region around sunspots. Possible initial oversegmentation of images is remedied with a median filter. The features are smoothed by using morphological closing operations and filled by applying watershed, followed by dilation operator to define regions of interest containing sunspots. A number of physical and geometrical parameters of detected sunspot features are extracted and stored in a relational database along with umbra-penumbra information in the form of pixel run-length data within a bounding rectangle. The detection results reveal very good agreement with the manual synoptic maps and a very high correlation with those produced manually by NOAA Observatory, USA.
Spectral Inversion of Multi-Line Full-Disk Observations of Quiet Sun Magnetic Fields
Balthasar, H
2012-01-01
Spectral inversion codes are powerful tools to analyze spectropolarimetric observations, and they provide important diagnostics of solar magnetic fields. Inversion codes differ by numerical procedures, approximations of the atmospheric model, and description of radiative transfer. Stokes Inversion based on Response functions (SIR) is an implementation widely used by the solar physics community. It allows to work with different atmospheric components, where gradients of different physical parameters are possible, e.g., magnetic field strength and velocities. The spectropolarimetric full-disk observations were carried out with the Stokesmeter of the Solar Telescope for Operative Predictions (STOP) at the Sayan Observatory on 3 February 2009, when neither an active region nor any other extended flux concentration was present on the Sun. In this study of quiet Sun magnetic fields, we apply the SIR code simultaneously to 15 spectral lines. A tendency is found that weaker magnetic field strengths occur closer to th...
Automatic Recognition of Sunspots in HSOS Full-Disk Solar Images
Zhao, Cui; Lin, GangHua; Deng, YuanYong; Yang, Xiao
2016-05-01
A procedure is introduced to recognise sunspots automatically in solar full-disk photosphere images obtained from Huairou Solar Observing Station, National Astronomical Observatories of China. The images are first pre-processed through Gaussian algorithm. Sunspots are then recognised by the morphological Bot-hat operation and Otsu threshold. Wrong selection of sunspots is eliminated by a criterion of sunspot properties. Besides, in order to calculate the sunspots areas and the solar centre, the solar limb is extracted by a procedure using morphological closing and erosion operations and setting an adaptive threshold. Results of sunspot recognition reveal that the number of the sunspots detected by our procedure has a quite good agreement with the manual method. The sunspot recognition rate is 95% and error rate is 1.2%. The sunspot areas calculated by our method have high correlation (95%) with the area data from the United States Air Force/National Oceanic and Atmospheric Administration (USAF/NOAA).
Automatic Recognition of Sunspots in HSOS Full-Disk Solar Images
Zhao, Cui; Deng, YuanYong; Yang, Xiao
2016-01-01
A procedure is introduced to recognise sunspots automatically in solar full-disk photosphere images obtained from Huairou Solar Observing Station, National Astronomical Observatories of China. The images are first pre-processed through Gaussian algorithm. Sunspots are then recognised by the morphological Bot-hat operation and Otsu threshold. Wrong selection of sunspots is eliminated by a criterion of sunspot properties. Besides, in order to calculate the sunspots areas and the solar centre, the solar limb is extracted by a procedure using morphological closing and erosion operations and setting an adaptive threshold. Results of sunspot recognition reveal that the number of the sunspots detected by our procedure has a quite good agreement with the manual method. The sunspot recognition rate is 95% and error rate is 1.2%. The sunspot areas calculated by our method have high correlation (95%) with the area data from USAF/NOAA.
Tracking magnetogram proper motions by multiscale regularization
Jones, Harrison P.
1995-01-01
Long uninterrupted sequences of solar magnetograms from the global oscillations network group (GONG) network and from the solar and heliospheric observatory (SOHO) satellite will provide the opportunity to study the proper motions of magnetic features. The possible use of multiscale regularization, a scale-recursive estimation technique which begins with a prior model of how state variables and their statistical properties propagate over scale. Short magnetogram sequences are analyzed with the multiscale regularization algorithm as applied to optical flow. This algorithm is found to be efficient, provides results for all the spatial scales spanned by the data and provides error estimates for the solutions. It is found that the algorithm is less sensitive to evolutionary changes than correlation tracking.
Recognition of Time Stamps on Full-Disk Hα Images Using Machine Learning Methods
Xu, Y.; Huang, N.; Jing, J.; Liu, C.; Wang, H.; Fu, G.
2016-12-01
Observation and understanding of the physics of the 11-year solar activity cycle and 22-year magnetic cycle are among the most important research topics in solar physics. The solar cycle is responsible for magnetic field and particle fluctuation in the near-earth environment that have been found increasingly important in affecting the living of human beings in the modern era. A systematic study of large-scale solar activities, as made possible by our rich data archive, will further help us to understand the global-scale magnetic fields that are closely related to solar cycles. The long-time-span data archive includes both full-disk and high-resolution Hα images. Prior to the widely use of CCD cameras in 1990s, 35-mm films were the major media to store images. The research group at NJIT recently finished the digitization of film data obtained by the National Solar Observatory (NSO) and Big Bear Solar Observatory (BBSO) covering the period of 1953 to 2000. The total volume of data exceeds 60 TB. To make this huge database scientific valuable, some processing and calibration are required. One of the most important steps is to read the time stamps on all of the 14 million images, which is almost impossible to be done manually. We implemented three different methods to recognize the time stamps automatically, including Optical Character Recognition (OCR), Classification Tree and TensorFlow. The latter two are known as machine learning algorithms which are very popular now a day in pattern recognition area. We will present some sample images and the results of clock recognition from all three methods.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
We have compared a set of co-temporal magnetograms obtained with the Solar Magnetic Field Tele-scope (SMFT) of the Huairou Solar Observing Station (HSOS) and with the Spectro-Polarimeter of the Solar Optical Telescope (SP/SOT) on board Hinode to check the linear calibrations of SMFT vector magnetograms. The comparison shows that the currently used calibration coefficients of the SMFT have under-estimated the flux density and that a center-to-limb variation of the calibration coefficients was not taken into account by previous calibrations.
Gosain, S; Rudenko, G V; Anfinogentov, S A
2013-01-01
We use daily full-disk vector magnetograms from Vector Spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) system to synthesize the first Carrington maps of the photospheric vector magnetic field. We describe these maps and make a comparison of observed radial field with the radial field estimate from LOS magnetograms. Further, we employ these maps to study the hemispheric pattern of current helicity density, Hc, during the rising phase of the solar cycle 24. Longitudinal average over the 23 consecutive solar rotations shows a clear signature of the hemispheric helicity rule, i.e. Hc is predominantly negative in the North and positive in South. Although our data include the early phase of cycle 24, there appears no evidence for a possible (systematic) reversal of the hemispheric helicity rule at the beginning of cycle as predicted by some dynamo models. Further, we compute the hemispheric pattern in active region latitudes (-30 deg \\le \\theta \\le 30 deg) separately for we...
Tessellation of SoHO Magnetograms
Indian Academy of Sciences (India)
R. Srikant; Jagdev Singh
2000-09-01
A gradient based algorithm which divides arbitrary images into non-overlapping surface filling tiles of opposite polarity is used to study the flux and size distributions of large scale magnetic flux concentrations in solar and heliospheric observatory (SoHO) magnetograms. The mean absolute flux and size of the concentrations at the considered scale is found to be about 1.7 × 1018Mx and 5.2Mm for both polarities. The form of the flux distribution is characterized by a skewness of 3 = 4.9 and a kurtosis of 4, = 42.8. The fall in the distribution in the range 6.5 × 1017Mx to 5 × 1018Mx is described by an exponential fit, in agreement with a model for the sustenance of quiet region flux.
Forecasting Safe or Dangerous Space Weather from HMI Magnetograms
Falconer, David; Barghouty, Abdulnasser F.; Khazanov, Igor; Moore, Ron
2011-01-01
We have developed a space-weather forecasting tool using an active-region free-energy proxy that was measured from MDI line-of-sight magnetograms. To develop this forecasting tool (Falconer et al 2011, Space Weather Journal, in press), we used a database of 40,000 MDI magnetograms of 1300 active regions observed by MDI during the previous solar cycle (cycle 23). From each magnetogram we measured our free-energy proxy and for each active region we determined its history of major flare, CME and Solar Particle Event (SPE) production. This database determines from the value of an active region s free-energy proxy the active region s expected rate of production of 1) major flares, 2) CMEs, 3) fast CMEs, and 4) SPEs during the next few days. This tool was delivered to NASA/SRAG in 2010. With MDI observations ending, we have to be able to use HMI magnetograms instead of MDI magnetograms. One of the difficulties is that the measured value of the free-energy proxy is sensitive to the spatial resolution of the measured magnetogram: the 0.5 /pixel resolution of HMI gives a different value for the free-energy proxy than the 2 /pixels resolution of MDI. To use our MDI-database forecasting curves until a comparably large HMI database is accumulated, we smooth HMI line-of-sight magnetograms to MDI resolution, so that we can use HMI to find the value of the free-energy proxy that MDI would have measured, and then use the forecasting curves given by the MDI database. The new version for use with HMI magnetograms was delivered to NASA/SRAG (March 2011). It can also use GONG magnetograms, as a backup.
Angular dependence of the facular-sunspot coverage relation as derived by MDI magnetograms
Criscuoli, Serena
2016-01-01
Previous studies have shown that the variation over the solar magnetic activity cycle of the area of facular/network features identified on broad band and narrow band imagery is positively correlated with the sunspot area and number, the relation between the area coverages being described as either linear or quadratic. On the other hand, the temporal variation of the spatial distributions of faculae, network and sunspots follows patterns that are less obviously correlated, so that we expect the relation that describes variation of the area coverage of different types of magnetic features to vary with the position over the disk. In this work we employ MDI full-disk magnetograms acquired during Cycle 23 and at the beginning of Cycle 24 to investigate the relation between the coverage of magnetic elements characterized by different amounts of magnetic flux and located at different angular distances from disk center with the sunspot number. In agreement with some previous studies we find that daily data are best ...
Angular Dependence of the Facular-Sunspot Coverage Relation as Derived by MDI Magnetograms
Criscuoli, S.
2016-08-01
Previous studies have shown that the variation over the solar magnetic activity cycle of the area of facular/network features identified from broad-band and narrow-band imagery is positively correlated with the sunspot area and number, the relation being described as either linear or quadratic. On the other hand, the temporal variation of the spatial distributions of faculae, network and sunspots follows patterns that are less obviously correlated, so that we expect the relation that describes variation of the area coverage of different types of magnetic features to vary with the position over the disk. In this work we employ Michelson Doppler Interferometer (MDI) full-disk magnetograms acquired during solar cycle 23 and at the beginning of cycle 24 to investigate the relation between the coverage of magnetic elements characterized by different amounts of magnetic flux and located at different angular distances from disk center with the sunspot number. In agreement with some previous studies we find that daily data are best described by a quadratic function while data averaged over six months are best described by a linear function. In both cases the coefficients of the fits show large dependence on the position over the disk and the magnetic flux. We also find that toward disk center six-month averaged data show asymmetries between the ascending and the descending phases. The implications for solar irradiance modeling are discussed.
2016-01-01
Documento que contiene la explicación sobre las temáticas de Sistemas coordenados, Cantidades vectoriales y escalares, Algunas propiedades de los vectores, Componentes de un vector y vectores unitarios
Full-disk observations of the saturnian moons in the VIS-NIR spectral range by Cassini- VIMS
Filacchione, G.; Capaccioni, F.; Coradini, A.; Cerroni, P.; Tosi, F.; Adriani, A.; McCord, T. B.; Baines, K. H.; Bellucci, G.; Brown, R. H.; Bibring, J.; Buratti, B. J.; Clark, R. N.; Combes, M.; Cruikshank, D. P.; Drossart, P.; Formisano, V.; Jaumann, R.; Langevin, Y.; Matson, D. L.; Mennella, V.; Robert, N. M.; Nicholson, P. D.; Sicardy, B.; Sotin, C.; Moriconi, M.
2006-12-01
During the first two years of the Cassini's nominal mission, VIMS (Visual and Infrared Mapping Spectrometer) has explored the whole system of Saturnian icy satellites. Here we report a comparative analysis of more than 600 full-disk observations obtained from July 2004 to nowadays for 15 regular and minor satellites: Atlas, Prometheus, Pandora, Janus, Epimetheus, Mimas, Enceladus, Tethys, Telesto, Calypso, Dione, Rhea, Hyperion, Iapetus and Phoebe. These observations, done from the equatorial plane, are particularly suitable to highlight the spectral differences between the leading and trailing sides of the regular satellites as function of the illumination angle (Filacchione et al., 2006a, 2006b); a byproduct of this activity is the measurement of the phase curves. The combined use of several VIS and IR spectral quantities (e.g. spectral slopes, water ice bands strengths, continuum levels, etc.) allows to find correlations between classes of satellites orbiting at different distances from Saturn: in this way it is possible to discriminate the almost pure ice surfaces of Enceladus and Calypso from the organic rich Hyperion, Iapetus and Phoebe (Tosi et al., 2006). This research was completed thanks to the support of the Italian Space Agency (ASI), Grant ASI/Cassini I/031/05/0. Filacchione et al., 2006a. Saturn's icy satellites investigated by Cassini-VIMS. I. Full-disk properties: 350-5100 nm reflectance spectra and phase curves, Icarus, in press. Filacchione et al., 2006b. VIS-NIR Spectral Properties of Saturn's Minor Icy Moons. 37th LPSC, abstract no.1271 Tosi et al., 2006. Iapetus, Phoebe and Hyperion: Are They Related? 37th LPSC, abstract no.1582
DEFF Research Database (Denmark)
Boeriis, Morten; van Leeuwen, Theo
2017-01-01
This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...... on the most salient vectors, and this works well, but many images contain a plethora of vectors, which makes their structure quite different from the linguistic transitivity structures with which Kress and van Leeuwen have compared ‘narrative’ images. It can also be asked whether facial expression vectors...... should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined...
Vector Magnetic Field Synoptic Charts from the Helioseismic and Magnetic Imager (HMI)
Liu, Yang; Hoeksema, J. Todd; Sun, Xudong; Hayashi, Keiji
2017-02-01
Vector magnetic field synoptic charts from the Helioseismic and Magnetic Imager (HMI) are now available for each Carrington Rotation (CR) starting from CR 2097 in May 2010. Synoptic charts are produced using 720-second cadence full-disk vector magnetograms remapped to Carrington coordinates. The vector field is derived from the Stokes parameters (I, Q, U, V) using a Milne-Eddington-based inversion model. The 180° azimuth ambiguity is resolved using the minimum energy algorithm for pixels in active regions and for strong-field pixels (the field is greater than about 150 G) in quiet-Sun regions. Three other methods are used for the rest of the pixels: the potential-field method, the radial acute-angle method, and the random method. The vector field synoptic charts computed using these three disambiguation methods are evaluated. The noise in the three components of the vector magnetic field is generally much higher in the potential-field method charts. The component noise levels are significantly different in the radial-acute charts. However, the noise levels in the random-method charts are lower and comparable. The assumptions used in the potential-field and radial-acute methods to disambiguate the weak transverse field introduce bias that propagates differently into the three vector-field components, leading to unreasonable pattern and artifacts, whereas the random method appears not to introduce any systematic bias. The current sheet on the source surface, computed using the potential-field source-surface model applied to random-method charts, agrees with the best solution (the result computed from the synoptic charts with the minimum energy algorithm applied to each and every pixel in the vector magnetograms) much better than the other two. Differences in the synoptic charts determined with the best method and the random method are much smaller than those from the best method and the other two. This comparison indicates that the random method is better for vector
MAGIC: A Tool for Combining, Interpolating, and Processing Magnetograms
Allred, Joel
2012-01-01
Transients in the solar coronal magnetic field are ultimately the source of space weather. Models which seek to track the evolution of the coronal field require magnetogram images to be used as boundary conditions. These magnetograms are obtained by numerous instruments with different cadences and resolutions. A tool is required which allows modelers to fmd all available data and use them to craft accurate and physically consistent boundary conditions for their models. We have developed a software tool, MAGIC (MAGnetogram Interpolation and Composition), to perform exactly this function. MAGIC can manage the acquisition of magneto gram data, cast it into a source-independent format, and then perform the necessary spatial and temporal interpolation to provide magnetic field values as requested onto model-defined grids. MAGIC has the ability to patch magneto grams from different sources together providing a more complete picture of the Sun's field than is possible from single magneto grams. In doing this, care must be taken so as not to introduce nonphysical current densities along the seam between magnetograms. We have designed a method which minimizes these spurious current densities. MAGIC also includes a number of post-processing tools which can provide additional information to models. For example, MAGIC includes an interface to the DA VE4VM tool which derives surface flow velocities from the time evolution of surface magnetic field. MAGIC has been developed as an application of the KAMELEON data formatting toolkit which has been developed by the CCMC.
Reconstruction of spectral solar irradiance since 1700 from simulated magnetograms
Dasi-Espuig, M; Krivova, N A; Solanki, S K; Unruh, Y C; Yeo, K L
2016-01-01
We present a reconstruction of the spectral solar irradiance since 1700 using the SATIRE-T2 (Spectral And Total Irradiance REconstructions for the Telescope era version 2) model. This model uses as input magnetograms simulated with a surface flux transport model fed with semi-synthetic records of emerging sunspot groups. We used statistical relationships between the properties of sunspot group emergence, such as the latitude, area, and tilt angle, and the sunspot cycle strength and phase to produce semi-synthetic sunspot group records starting in the year 1700. The semisynthetic records are fed into a surface flux transport model to obtain daily simulated magnetograms that map the distribution of the magnetic flux in active regions (sunspots and faculae) and their decay products on the solar surface. The magnetic flux emerging in ephemeral regions is accounted for separately based on the concept of extended cycles whose length and amplitude are linked to those of the sunspot cycles through the sunspot number....
Energy Technology Data Exchange (ETDEWEB)
Gosain, S.; Pevtsov, A. A. [National Solar Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Rudenko, G. V.; Anfinogentov, S. A. [Institute of Solar-Terrestrial Physics (ISTP), Russian Academy of Sciences, Irkutsk (Russian Federation)
2013-07-20
We use daily full-disk vector magnetograms from Vector Spectromagnetograph on Synoptic Optical Long-term Investigations of the Sun system to synthesize the first Carrington maps of the photospheric vector magnetic field. We describe these maps and make a comparison of the observed radial field with the radial field estimate from line-of-sight magnetograms. Furthermore, we employ these maps to study the hemispheric pattern of current helicity density, H{sub c} , during the rising phase of solar cycle 24. The longitudinal average over the 23 consecutive solar rotations shows a clear signature of the hemispheric helicity rule, i.e., H{sub c} is predominantly negative in the north and positive in the south. Although our data include the early phase of cycle 24, there appears to be no evidence for a possible (systematic) reversal of the hemispheric helicity rule at the beginning of the cycle as predicted by some dynamo models. Furthermore, we compute the hemispheric pattern in active region latitudes (-30 Degree-Sign {<=} {theta} {<=} 30 Degree-Sign ) separately for weak (100 G < |B{sub r} | < 500 G) and strong (|B{sub r} | > 1000 G) radial magnetic fields. We find that while the current helicity of strong fields follows the well-known hemispheric rule (i.e., {theta} {center_dot} H{sub c} < 0), H{sub c} of weak fields exhibits an inverse hemispheric behavior (i.e., {theta} {center_dot} H{sub c} > 0), albeit with large statistical scatter. We discuss two plausible scenarios to explain the opposite hemispheric trend of helicity in weak and strong field regions.
Ahn, Kwangsu; Cao, Wenda; Shumko, Sergiy; Chae, Jongchul
2016-05-01
We want to present the processing result of the vector magnetograms from the Near InfraRed Imaging Spectropolarimeter (NIRIS) at Big Bear Solar Observatory. The NIRIS is a successor of an old magnetograph system at BBSO, which equips with the new infrared detector and the improved Fabry-Perot filter system. While there are several upgrades to the new hardware, there are also some challenges as the data acquisition rate increases and we deal with the a larger detector array. The overall process includes dark and flat correction, image alignment, de-stretch, Stokes parameter selection, calibration of instrumental crosstalk, and Milne-Eddington inversion.
Worldwide Magnetograms with Geomagnetic Components D, H, Z, or X, Y, and Z
National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) receives magnetograms from over 200 geomagnetic observatories....
Magnetogram Forecast: An All-Clear Space Weather Forecasting System
Barghouty, Nasser; Falconer, David
2015-01-01
Solar flares and coronal mass ejections (CMEs) are the drivers of severe space weather. Forecasting the probability of their occurrence is critical in improving space weather forecasts. The National Oceanic and Atmospheric Administration (NOAA) currently uses the McIntosh active region category system, in which each active region on the disk is assigned to one of 60 categories, and uses the historical flare rates of that category to make an initial forecast that can then be adjusted by the NOAA forecaster. Flares and CMEs are caused by the sudden release of energy from the coronal magnetic field by magnetic reconnection. It is believed that the rate of flare and CME occurrence in an active region is correlated with the free energy of an active region. While the free energy cannot be measured directly with present observations, proxies of the free energy can instead be used to characterize the relative free energy of an active region. The Magnetogram Forecast (MAG4) (output is available at the Community Coordinated Modeling Center) was conceived and designed to be a databased, all-clear forecasting system to support the operational goals of NASA's Space Radiation Analysis Group. The MAG4 system automatically downloads nearreal- time line-of-sight Helioseismic and Magnetic Imager (HMI) magnetograms on the Solar Dynamics Observatory (SDO) satellite, identifies active regions on the solar disk, measures a free-energy proxy, and then applies forecasting curves to convert the free-energy proxy into predicted event rates for X-class flares, M- and X-class flares, CMEs, fast CMEs, and solar energetic particle events (SPEs). The forecast curves themselves are derived from a sample of 40,000 magnetograms from 1,300 active region samples, observed by the Solar and Heliospheric Observatory Michelson Doppler Imager. Figure 1 is an example of MAG4 visual output
Improved magnetogram calibration of SMFT and its comparison with the HMI
Bai, Xianyong; Teng, Fei; Su, Jiangtao; Mao, Xinjie; Wang, Guoping
2014-01-01
In this paper, we try to improve the magnetogram calibration method of the Solar Magnetic Field Telescope (SMFT). The improved calibration process fits the observed full Stokes information, using six points on the profile of Fe {\\i} 5324.18 {\\AA} line, and the analytical Stokes profiles under the Milne-Eddington atmosphere model, adopting the Levenberg-Marquardt least-square fitting algorithm. In Comparison with the linear calibration methods, which employs one point, there is large difference in the strength of longitudinal field $B_l$ and tranverse field $B_t$, caused by the non-linear relationship, but the discrepancy is little in the case of inclination and azimuth. We conclude that it is better to deal with the non-linear effects in the calibration of $B_l$ and $B_t$ using six points. Moreover, in comparison with SDO/HMI, SMFT has larger stray light and acquires less magnetic field strength. For vector magnetic fields in two sunspot regions, the magnetic field strength, inclination and azimuth angles bet...
Reconstruction of spectral solar irradiance since 1700 from simulated magnetograms
Dasi-Espuig, M.; Jiang, J.; Krivova, N. A.; Solanki, S. K.; Unruh, Y. C.; Yeo, K. L.
2016-05-01
Aims: We present a reconstruction of the spectral solar irradiance since 1700 using the SATIRE-T2 (Spectral And Total Irradiance REconstructions for the Telescope era version 2) model. This model uses as input magnetograms simulated with a surface flux transport model fed with semi-synthetic records of emerging sunspot groups. Methods: The record of sunspot group areas and positions from the Royal Greenwich Observatory (RGO) is only available since 1874. We used statistical relationships between the properties of sunspot group emergence, such as the latitude, area, and tilt angle, and the sunspot cycle strength and phase to produce semi-synthetic sunspot group records starting in the year 1700. The semi-synthetic records are fed into a surface flux transport model to obtain daily simulated magnetograms that map the distribution of the magnetic flux in active regions (sunspots and faculae) and their decay products on the solar surface. The magnetic flux emerging in ephemeral regions is accounted for separately based on the concept of extended cycles whose length and amplitude are linked to those of the sunspot cycles through the sunspot number. The magnetic flux in each surface component (sunspots, faculae and network, and ephemeral regions) was used to compute the spectral and total solar irradiance (TSI) between the years 1700 and 2009. This reconstruction is aimed at timescales of months or longer although the model returns daily values. Results: We found that SATIRE-T2, besides reproducing other relevant observations such as the total magnetic flux, reconstructs the TSI on timescales of months or longer in good agreement with the PMOD composite of observations, as well as with the reconstruction starting in 1878 based on the RGO-SOON data. The model predicts an increase in the TSI of 1.2+0.2-0.3 Wm-2 between 1700 and the present. The spectral irradiance reconstruction is in good agreement with the UARS/SUSIM measurements as well as the Lyman-α composite. The
Estimating stellar wind parameters from low-resolution magnetograms
Jardine, M.; Vidotto, A. A.; See, V.
2017-02-01
Stellar winds govern the angular momentum evolution of solar-like stars throughout their main-sequence lifetime. The efficiency of this process depends on the geometry of the star's magnetic field. There has been a rapid increase recently in the number of stars for which this geometry can be determined through spectropolarimetry. We present a computationally efficient method to determine the 3D geometry of the stellar wind and to estimate the mass-loss rate and angular momentum loss rate based on these observations. Using solar magnetograms as examples, we quantify the extent to which the values obtained are affected by the limited spatial resolution of stellar observations. We find that for a typical stellar surface resolution of 20o-30o, predicted wind speeds are within 5 per cent of the value at full resolution. Mass-loss rates and angular momentum loss rates are within 5-20 per cent. In contrast, the predicted X-ray emission measures can be underestimated by one-to-two orders of magnitude, and their rotational modulations by 10-20 per cent.
Estimating stellar wind parameters from low-resolution magnetograms
Jardine, Moira; See, Victor
2016-01-01
Stellar winds govern the angular momentum evolution of solar-like stars throughout their main-sequence lifetime. The efficiency of this process depends on the geometry of the star's magnetic field. There has been a rapid increase recently in the number of stars for which this geometry can be determined through spectropolarimetry. We present a computationally efficient method to determine the 3D geometry of the stellar wind and to estimate the mass loss rate and angular momentum loss rate based on these observations. Using solar magnetograms as examples, we quantify the extent to which the values obtained are affected by the limited spatial resolution of stellar observations. We find that for a typical stellar surface resolution of 20$^{\\rm o}$-30$^{\\rm o}$, predicted wind speeds are within 5$\\%$ of the value at full resolution. Mass loss rates and angular momentum loss rates are within 5-20$\\%$. In contrast, the predicted X-ray emission measures can be under-estimated by 1-2 orders of magnitude, and their rot...
Predicting Solar Flares Using SDO/HMI Vector Magnetic Data Product and Random Forest Algorithm
Liu, Chang; Deng, Na; Wang, Jason; Wang, Haimin
2017-08-01
Adverse space weather effects can often be traced to solar flares, prediction of which has drawn significant research interests. Many previous forecasting studies used physical parameters derived from photospheric line-of-sight field or ground-based vector field observations. The Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory produces full-disk vector magnetograms with continuous high-cadence, while flare prediction efforts utilizing this unprecedented data source are still limited. Here we report results of flare prediction using physical parameters provided by the Space-weather HMI Active Region Patches (SHARP) and related data products. We survey X-ray flares occurred from 2010 May to 2016 December, and categorize their source regions into four classes (B, C, M, and X) according to the maximum GOES magnitude of flares they generated. We then retrieve SHARP related parameters for each selected region at the beginning of its flare date to build a database. Finally, we train a machine-learning algorithm, called random forest (RF), to predict the occurrence of a certain class of flares in a given active region within 24 hours, evaluate the classifier performance using the 10-fold cross validation scheme, and characterize the results using standard performace metrics. Compared to previous works, our experiments indicate that using the HMI parameters and RF is a valid method for flare forecasting with fairly reasonable prediction performance. We also find that the total unsigned quantities of vertical current, current helicity, and flux near polarity inversion line are among the most important parameters for classifying flaring regions into different classes.
Predicting Solar Flares Using SDO/HMI Vector Magnetic Data Products and the Random Forest Algorithm
Liu, Chang; Deng, Na; Wang, Jason T. L.; Wang, Haimin
2017-07-01
Adverse space-weather effects can often be traced to solar flares, the prediction of which has drawn significant research interests. The Helioseismic and Magnetic Imager (HMI) produces full-disk vector magnetograms with continuous high cadence, while flare prediction efforts utilizing this unprecedented data source are still limited. Here we report results of flare prediction using physical parameters provided by the Space-weather HMI Active Region Patches (SHARP) and related data products. We survey X-ray flares that occurred from 2010 May to 2016 December and categorize their source regions into four classes (B, C, M, and X) according to the maximum GOES magnitude of flares they generated. We then retrieve SHARP-related parameters for each selected region at the beginning of its flare date to build a database. Finally, we train a machine-learning algorithm, called random forest (RF), to predict the occurrence of a certain class of flares in a given active region within 24 hr, evaluate the classifier performance using the 10-fold cross-validation scheme, and characterize the results using standard performance metrics. Compared to previous works, our experiments indicate that using the HMI parameters and RF is a valid method for flare forecasting with fairly reasonable prediction performance. To our knowledge, this is the first time that RF has been used to make multiclass predictions of solar flares. We also find that the total unsigned quantities of vertical current, current helicity, and flux near the polarity inversion line are among the most important parameters for classifying flaring regions into different classes.
Space Weather Parameters Computed on the Basis of the Magnetogram Inversion Technique
Institute of Scientific and Technical Information of China (English)
V. M. Mishin; M. F(o)rster; A.D. Bazarzhapov; T.I. Saifudinova; Y.A. Karavaev; P. Stauning; J. Watermann; V. Golovkov; S. Solovyev
2005-01-01
In this paper is given short description of the magnetogram inversion technique, MIT2, and of methods of calculation of some parameters of space weather. Are given also examples of new results, obtained using the MIT2 and solar wind data.
Real-Time CME Forecasting Using HMI Active-Region Magnetograms and Flare History
Falconer, David; Moore, Ron; Barghouty, Abdulnasser F.; Khazanov, Igor
2011-01-01
We have recently developed a method of predicting an active region s probability of producing a CME, an X-class Flare, an M-class Flare, or a Solar Energetic Particle Event from a free-energy proxy measured from SOHO/MDI line-of-sight magnetograms. This year we have added three major improvements to our forecast tool: 1) Transition from MDI magnetogram to SDO/HMI magnetogram allowing us near-real-time forecasts, 2) Automation of acquisition and measurement of HMI magnetograms giving us near-real-time forecasts (no older than 2 hours), and 3) Determination of how to improve forecast by using the active region s previous flare history in combination with its free-energy proxy. HMI was turned on in May 2010 and MDI was turned off in April 2011. Using the overlap period, we have calibrated HMI to yield what MDI would measure. This is important since the value of the free-energy proxy used for our forecast is resolution dependent, and the forecasts are made from results of a 1996-2004 database of MDI observations. With near-real-time magnetograms from HMI, near-real-time forecasts are now possible. We have augmented the code so that it continually acquires and measures new magnetograms as they become available online, and updates the whole-sun forecast from the coming day. The next planned improvement is to use an active region s previous flare history, in conjunction with its free-energy proxy, to forecast the active region s event rate. It has long been known that active regions that have produced flares in the past are likely to produce flares in the future, and that active regions that are nonpotential (have large free-energy) are more likely to produce flares in the future. This year we have determined that persistence of flaring is not just a reflection of an active region s free energy. In other words, after controlling for free energy, we have found that active regions that have flared recently are more likely to flare in the future.
Forecasting the Solar Drivers of Severe Space Weather from Active-Region Magnetograms
Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor
2012-01-01
Solar drivers of severe space weather can be predicted from line-of-sight magnetograms, via a free-energy proxy measured from the neutral lines. This can be done in near real time. In addition to depending strongly on the free magnetic energy, an active region's chance of having a major eruption depends strongly on other aspects of the evolving magnetic field (e.g., its complexity and flux emergence).
MANGO - A Magnetogram Analysis Service for Enhancement of the Heliophysics Data Environment
Bargatze, L. F.
2011-12-01
The Heliophysics Data Environment Enhancement program supports efforts to integrate data services for conducting research of solar-terrestrial interactions. MANGO, Magnetogram Analysis for the Network of Geophysical Observatories, is a service that is directed at Heliophysics researchers interested in processing magnetic field data from ground magnetometers. Ground magnetograms are essential for monitoring the response of the magnetosphere to solar wind coupling. For instance, it is difficult to understand how spacecraft particle and field variations fit in context of activity throughout the global magnetospheric system without using ground magnetic field data. The MANGO service package allows one to decompose ground magnetic field variations and estimate the relative contributions from secular, diurnal, ring current, and auroral current systems. The MANGO service package leverages the SPASE metadata registries of the Virtual Magnetospheric Observatory (VMO) to compile a list of available magnetogram data products. Currently, MANGO provides access to over 900 data products from about 350 ground magnetic field stations located around the globe. The VMO SPASE Granule registry contains ~150,000 files that comprise the MANGO relevant data products. And, the VMO Granule registry count is steadily increasing as more data products are described and ingested. Data selection from the distributed network of stations is naturally aided by using a world map to display the set of observatories. The MANGO web site (http://mango.igpp.ucla.edu), plots stations on a map that have data products, which meet user-defined criteria based on time of observation, station location, time cadence, magnetometer chain, etc. Note that Many of the ground magnetogram and geomagnetic index data products relevant to the MANGO effort are only available from their data providers in formats that allow the data to be packed. The formats used, and there are many types, save time in file retrieval and
Simulating the formation of a sigmoidal flux rope in AR10977 from SOHO/MDI magnetograms
Energy Technology Data Exchange (ETDEWEB)
Gibb, G. P. S.; Mackay, D. H.; Meyer, K. A. [University of St Andrews, School of Mathematics and Statistics, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Green, L. M. [University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)
2014-02-20
The modeling technique of Mackay et al. is applied to simulate the coronal magnetic field of NOAA active region AR10977 over a seven day period (2007 December 2-10). The simulation is driven with a sequence of line-of-sight component magnetograms from SOHO/MDI and evolves the coronal magnetic field though a continuous series of non-linear force-free states. Upon comparison with Hinode/XRT observations, results show that the simulation reproduces many features of the active region's evolution. In particular, it describes the formation of a flux rope across the polarity inversion line during flux cancellation. The flux rope forms at the same location as an observed X-ray sigmoid. After five days of evolution, the free magnetic energy contained within the flux rope was found to be 3.9 × 10{sup 30} erg. This value is more than sufficient to account for the B1.4 GOES flare observed from the active region on 2007 December 7. At the time of the observed eruption, the flux rope was found to contain 20% of the active region flux. We conclude that the modeling technique proposed in Mackay et al.—which directly uses observed magnetograms to energize the coronal field—is a viable method to simulate the evolution of the coronal magnetic field.
An empirical method to correct the saturation seen in the SOHOIMDI magnetograms
Institute of Scientific and Technical Information of China (English)
Zhendong Gao; Yong-Heng Zhao; Yang Liu
2010-01-01
The magnetic field of the umbrae is sometimes found to be saturated in the magnetograms taken by the Michelson Doppler Imager(MDI)onboard the Solar and Heliospberic Observatory(SOHO).It is suggested that the combination of the low intensity of sunspot umbrae and the limitation of the 15-bit onboard numerical data acquisition leads to this saturation.In this paper,we propose to use the MDI's intensity data to correct this saturation.This method is based on the well-established relationship between the continuum intensity and the magnetic field(the so-called I-B relationship).A comparison between the corrected magnetic field and the data taken by the Stokes-Polarimeter of the Solar Optical Telescope(SOT/SP)onboard Hinode shows a reasonable agreement,suggesting that this correction is effective.
Roche, John
1997-01-01
Suggests an approach to teaching vectors that promotes active learning through challenging questions addressed to the class, as opposed to subtle explanations. Promotes introducing vector graphics with concrete examples, beginning with an explanation of the displacement vector. Also discusses artificial vectors, vector algebra, and unit vectors.…
Bogoutdinov, Sh. R.; Gvishiani, A. D.; Agayan, S. M.; Solovyev, A. A.; Kin, E.
2010-11-01
The International Real-time Magnetic Observatory Network (INTERMAGNET) is the world's biggest international network of ground-based observatories, providing geomagnetic data almost in real time (within 72 hours of collection) [Kerridge, 2001]. The observation data are rapidly transferred by the observatories participating in the program to regional Geomagnetic Information Nodes (GINs), which carry out a global exchange of data and process the results. The observations of the main (core) magnetic field of the Earth and its study are one of the key problems of geophysics. The INTERMAGNET system is the basis of monitoring the state of the Earth's magnetic field; therefore, the information provided by the system is required to be very reliable. Despite the rigid high-quality standard of the recording devices, they are subject to external effects that affect the quality of the records. Therefore, an objective and formalized recognition with the subsequent remedy of the anomalies (artifacts) that occur on the records is an important task. Expanding on the ideas of Agayan [Agayan et al., 2005] and Gvishiani [Gvishiani et al., 2008a; 2008b], this paper suggests a new algorithm of automatic recognition of anomalies with specified morphology, capable of identifying both physically- and anthropogenically-derived spikes on the magnetograms. The algorithm is constructed using fuzzy logic and, as such, is highly adaptive and universal. The developed algorithmic system formalizes the work of the expert-interpreter in terms of artificial intelligence. This ensures identical processing of large data arrays, almost unattainable manually. Besides the algorithm, the paper also reports on the application of the developed algorithmic system for identifying spikes at the INTERMAGNET observatories. The main achievement of the work is the creation of an algorithm permitting the almost unmanned extraction of spike-free (definitive) magnetograms from preliminary records. This automated
Energy Technology Data Exchange (ETDEWEB)
Meyer, K. A.; Sabol, J.; Mackay, D. H. [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Van Ballegooijen, A. A., E-mail: karen@mcs.st-and.ac.uk [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2013-06-20
In recent years, higher cadence, higher resolution observations have revealed the quiet-Sun photosphere to be complex and rapidly evolving. Since magnetic fields anchored in the photosphere extend up into the solar corona, it is expected that the small-scale coronal magnetic field exhibits similar complexity. For the first time, the quiet-Sun coronal magnetic field is continuously evolved through a series of non-potential, quasi-static equilibria, deduced from magnetograms observed by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, where the photospheric boundary condition which drives the coronal evolution exactly reproduces the observed magnetograms. The build-up, storage, and dissipation of magnetic energy within the simulations is studied. We find that the free magnetic energy built up and stored within the field is sufficient to explain small-scale, impulsive events such as nanoflares. On comparing with coronal images of the same region, the energy storage and dissipation visually reproduces many of the observed features. The results indicate that the complex small-scale magnetic evolution of a large number of magnetic features is a key element in explaining the nature of the solar corona.
Hoffmann, Banesh
1975-01-01
From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p
Newell, Homer E
2006-01-01
When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e
Studies of Solar Vector Magnetic Field
Institute of Scientific and Technical Information of China (English)
WANG Jingxiu
2011-01-01
In this article, we report a few advances in the studies based on the solar vector magnetic field observations which were carried out mainly with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station in the 1990s. （1） We developed necessary methodology and concepts in vector magnetogram analysis （Wang et al. 1996）. For the first time, we proposed to use the photospheric free magnetic energy to quantify the major flare productivity of solar active regions （ARs）, and it had been proved to be the best parameter in representing the major flare activity. （2） We revealed that there was always a dominant sense of magnetic shear in a given AR （Wang 1994）, which was taken as the premise of the helicity calculation in ARs; we made the first quantitative estimation of magnetic helicity evolution in ARs （Wang 1996）. （3） We identified the first group of evidence of magnetic reconnection in the lower solar atmosphere with vector magnetic field observations and proposed a two-step reconnection flare model to interpret the observed association of flux cancellation and flares （Wang and Shi 1993）. Efforts to quantify the major flare productivity of super active regions with vector magnetic field observations have been also taken.
Wolstenholme, E Œ
1978-01-01
Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl
Brand, Louis
2006-01-01
The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou
Guilfoyle, R.A.; Smith, L.M.
1994-12-27
A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.
Guilfoyle, Richard A.; Smith, Lloyd M.
1994-01-01
A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.
Fisher, George H; Bercik, David J; Kazachenko, Maria D; Lynch, Benjamin J; Welsch, Brian T; Hoeksema, J Todd; Hayashi, Keiji; Liu, Yang; Norton, Aimee A; Dalda, Alberto Sainz; Sun, Xudong; DeRosa, Marc L; Cheung, Mark C M
2015-01-01
The most violent space weather events (eruptive solar flares and coronal mass ejections) are driven by the release of free magnetic energy stored in the solar corona. Energy can build up on timescales of hours to days, and then may be suddenly released in the form of a magnetic eruption, which then propagates through interplanetary space, possibly impacting the Earth's space environment. Can we use the observed evolution of the magnetic and velocity fields in the solar photosphere to model the evolution of the overlying solar coronal field, including the storage and release of magnetic energy in such eruptions? The objective of CGEM, the Coronal Global Evolutionary Model, funded by the NASA/NSF Space Weather Modeling program, is to develop and evaluate such a model for the evolution of the coronal magnetic field. The evolving coronal magnetic field can then be used as a starting point for magnetohydrodynamic (MHD) models of the corona, which can then be used to drive models of heliospheric evolution and predi...
Fisher, G. H.; Abbett, W. P.; Bercik, D. J.; Kazachenko, M. D.; Lynch, B. J.; Welsch, B. T.; Hoeksema, J. T.; Hayashi, K.; Liu, Y.; Norton, A. A.; Dalda, A. Sainz; Sun, X.; DeRosa, M. L.; Cheung, M. C. M.
2015-06-01
The most violent space weather events (eruptive solar flares and coronal mass ejections) are driven by the release of free magnetic energy stored in the solar corona. Energy can build up on timescales of hours to days, and then may be suddenly released in the form of a magnetic eruption, which then propagates through interplanetary space, possibly impacting the Earth's space environment. Can we use the observed evolution of the magnetic and velocity fields in the solar photosphere to model the evolution of the overlying solar coronal field, including the storage and release of magnetic energy in such eruptions? The objective of CGEM, the Coronal Global Evolutionary Model, funded by the NASA/NSF Space Weather Modeling program, is to develop and evaluate such a model for the evolution of the coronal magnetic field. The evolving coronal magnetic field can then be used as a starting point for magnetohydrodynamic (MHD) models of the corona, which can then be used to drive models of heliospheric evolution and predictions of magnetic field and plasma density conditions at 1AU.
The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance
Hoeksema, J Todd; Hayashi, Keiji; Sun, Xudong; Schou, Jesper; Couvidat, Sebastien; Norton, Aimee; Bobra, Monica; Centeno, Rebecca; Leka, K D; Barnes, Graham; Turmon, Michael J
2014-01-01
The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable quantities, including the photospheric vector magnetic field, from sequences of filtergrams. The primary 720s observables were released in mid 2010, including Stokes polarization parameters measured at six wavelengths as well as intensity, Doppler velocity, and the line-of-sight magnetic field. More advanced products, including the full vector magnetic field, are now available. Automatically identified HMI Active Region Patches (HARPs) track the location and shape of magnetic regions throughout their lifetime. The vector field is computed using the Very Fast Inversion of the Stokes Vector (VFISV) code optimized for the HMI pipeline; the remaining 180 degree azimuth ambiguity is resolved with the Minimum Energy (ME0) code. The Milne-Eddington inversion is performed on all full-di...
Robinson, Gilbert de B
2011-01-01
This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom
Solar Imagery - GONG (Magnetogram)
National Oceanic and Atmospheric Administration, Department of Commerce — The Global Oscillation Network Group (GONG) is a network of 6 globally-spaced solar observatories that the NOAA Space Weather Prediction Center uses to monitor the...
DEFF Research Database (Denmark)
2012-01-01
The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...... assembly for emission of a measurement beam for illumination of an object in a measurement volume with coherent light whereby a signal beam emanating from the object in the measurement volume is formed in response to illumination of the object by the measurement beam, a reference beam generator...... detector element signal when the fringe pattern formed by the interfering signal beam and reference beam moves across the first detector array; and a signal processor that is adapted for generation of a velocity signal corresponding to a first velocity component of movement of the object in the measurement...
DEFF Research Database (Denmark)
2012-01-01
for generation of a reference beam, a detector system comprising a first detector arrangement arranged in such a way that the signal beam and the reference beam are incident upon the first detector arrangement with the reference beam propagating at an angle relative to a signal beam, and wherein the first......The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...... assembly for emission of a measurement beam for illumination of an object in a measurement volume with coherent light whereby a signal beam emanating from the object in the measurement volume is formed in response to illumination of the object by the measurement beam, a reference beam generator...
The HMI Magnetic Field Pipeline
Hoeksema, Jon Todd; Liu, Y.; Schou, J.; Scherrer, P.; HMI Science Team
2009-05-01
The Helioseismic and Magnetic Imager (HMI) will provide frequent full-disk magnetic field data after launch of the Solar Dynamics Observatory (SDO), currently scheduled for fall 2009. 16 megapixel line-of-sight magnetograms (Blos) will be recorded every 45 seconds. A full set of polarized filtergrams needed to determine the vector magnetic field requires 90 seconds. Quick-look data will be available within a few minutes of observation. Quick-look space weather and browse products must have identified users, and the list currently includes full disk magnetograms, feature identification and movies, 12-minute disambiguated vector fields in active region patches, time evolution of AR indices, synoptic synchronic frames, potential and MHD model results, and 1 AU predictions. A more complete set of definitive science data products will be offered about a day later and come in three types. "Pipeline” products, such as full disk vector magnetograms, will be computed for all data on an appropriate cadence. A larger menu of "On Demand” products, such as Non-Linear Force Free Field snapshots of an evolving active region, will be produced whenever a user wants them. Less commonly needed "On Request” products that require significant project resources, such as a high resolution MHD simulation of the global corona, will be created subject to availability of resources. Further information can be found at the SDO Joint Science Operations Center web page, jsoc.stanford.edu
Hayashi, Keiji; Liu, Yang; Bobra, Monica G; Sun, Xudong D; Norton, Aimee A
2015-01-01
Time-dependent three-dimensional magnetohydrodynamics (MHD) simulation modules are implemented at the Joint Science Operation Center (JSOC) of Solar Dynamics Observatory (SDO). The modules regularly produce three-dimensional data of the time-relaxed minimum-energy state of the solar corona using global solar-surface magnetic-field maps created from Helioseismic Magnetic Imager (HMI) full-disk magnetogram data. With the assumption of polytropic gas with specific heat ratio of 1.05, three types of simulation products are currently generated: i) simulation data with medium spatial resolution using the definitive calibrated synoptic map of the magnetic field with a cadence of one Carrington rotation, ii) data with low spatial resolution using the definitive version of the synchronic frame format of the magnetic field, with a cadence of one day, and iii) low-resolution data using near-real-time (NRT) synchronic format of the magnetic field on daily basis. The MHD data available in the JSOC database are three-dimen...
Another Piece of the Elephant: Chromospheric Vector Field Observations
Leka, K. D.; Metcalf, T. R.; Mickey, D. L.
2005-05-01
As with most solar observational questions, investigating the structure and role of the chromosphere is one of remote sensing: many investigations describing their "piece of the elephant". The goal is, of course, to form a coherent picture of the state of the magnetized plasma which resides there (or passes through). In this presentation, recent efforts to understand the chromospheric magnetic field structure via direct observation, i.e. chromospheric vector magnetograms, will be presented. Since late 2003, the U. Hawai`i/Mees Solar Observatory's Imaging Vector Magnetograph has routinely acquired spectropolarimetry measurements of active regions across the Na-I 589.6nm line; from the polarization at the line's near-wings approximately 0.007nm from line center we deduce the vector magnetic field. The data are specific to active regions, with the focus being the structure, free energy storage and evolution at that low-chromospheric layer. I will present salient aspects of the observed chromospheric magnetic field structure, to compare and contrast with the picture formed by the other methods in this session.
Quantifying solar superactive regions with vector magnetic field observations
Chen, A Q
2012-01-01
The vector magnetic field characteristics of superactive regions (SARs) hold the key for understanding why SARs are extremely active and provide the guidance in space weather prediction. We aim to quantify the characteristics of SARs using the vector magnetograms taken by the Solar Magnetic Field Telescope at Huairou Solar Observatory Station. The vector magnetic field characteristics of 14 SARs in solar cycles 22 and 23 were analyzed using the following four parameters: 1) the magnetic flux imbalance between opposite polarities, 2) the total photospheric free magnetic energy, 3) the length of the magnetic neutral line with its steep horizontal magnetic gradient, and 4) the area with strong magnetic shear. Furthermore, we selected another eight large and inactive active regions (ARs), which are called fallow ARs (FARs), to compare them with the SARs. We found that most of the SARs have a net magnetic flux higher than 7.0\\times10^21 Mx, a total photospheric free magnetic energy higher than 1.0\\times10^24 erg/c...
Nonlinear force-free modelling: influence of inaccuracies in the measured magnetic vector
Wiegelmann, T; Solanki, S K; Lagg, A
2009-01-01
Context: Solar magnetic fields are regularly extrapolated into the corona starting from photospheric magnetic measurements that can suffer from significant uncertainties. Aims: Here we study how inaccuracies introduced into the maps of the photospheric magnetic vector from the inversion of ideal and noisy Stokes parameters influence the extrapolation of nonlinear force-free magnetic fields. Methods: We compute nonlinear force-free magnetic fields based on simulated vector magnetograms, which have been produced by the inversion of Stokes profiles, computed froma 3-D radiation MHD simulation snapshot. These extrapolations are compared with extrapolations starting directly from the field in the MHD simulations, which is our reference. We investigate how line formation and instrumental effects such as noise, limited spatial resolution and the effect of employing a filter instrument influence the resulting magnetic field structure. The comparison is done qualitatively by visual inspection of the magnetic field dis...
Horikis, Theodoros P
2016-01-01
Families of soliton pairs, namely vector solitons, are found within the context of a coupled nonlocal nonlinear Schrodinger system of equations, as appropriate for modeling beam propagation in nematic liquid crystals. In the focusing case, bright soliton pairs have been found to exist provided their amplitudes satisfy a specific condition. In our analytical approach, focused on the defocusing regime, we rely on a multiscale expansion methods, which reveals the existence of dark-dark and antidark-antidark solitons, obeying an effective Korteweg-de Vries equation, as well as dark-bright solitons, obeying an effective Mel'nikov system. These pairs are discriminated by the sign of a constant that links all physical parameters of the system to the amplitude of the stable continuous wave solutions, and, much like the focusing case, the solitons' amplitudes are linked leading to mutual guiding.
Rotations with Rodrigues' Vector
Pina, E.
2011-01-01
The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…
Mishin, V. V.; Mishin, V. M.; Karavaev, Yu.; Han, J. P.; Wang, C.
2016-07-01
We report on novel features of the saturation process of the polar cap magnetic flux and Poynting flux into the magnetosphere from the solar wind during three superstorms. In addition to the well-known effect of the interplanetary electric (Esw) and southward magnetic (interplanetary magnetic field (IMF) Bz) fields, we found that the saturation depends also on the solar wind ram pressure Pd. By means of the magnetogram inversion technique and a global MHD numerical model Piecewise Parabolic Method with a Lagrangian Remap, we explore the dependence of the magnetopause standoff distance on ram pressure and the southward IMF. Unlike earlier studies, in the considered superstorms both Pd and Bz achieve extreme values. As a result, we show that the compression rate of the dayside magnetosphere decreases with increasing Pd and the southward Bz, approaching very small values for extreme Pd ≥ 15 nPa and Bz ≤ -40 nT. This dependence suggests that finite compressibility of the magnetosphere controls saturation of superstorms.
A New Method of Identifying 3D Null Points in Solar Vector Magnetic Fields
Institute of Scientific and Technical Information of China (English)
Hui Zhao; Jing-Xiu Wang; Jun Zhang; Chi-Jie Xiao
2005-01-01
Employing the Poincaré index of isolated null-points in a vector field,we worked out a mathematical method of searching for 3D null-points in coronal magnetic fields. After introducing the relevant differential topology, we test the method by using the analytical model of Brown & Priest. The location of nullpoint identified by our method coincides precisely with the analytical solution.Finally we apply the method to the 3D coronal magnetic fields reconstructed from an observed MDI magnetogram of a super-active region (NOAA 10488). We find that the 3D null-point seems to be a key element in the magnetic topology associated with flare occurrence.
Eliezer, C J; Maxwell, E A; Sneddon, I N
1963-01-01
Concise Vector Analysis is a five-chapter introductory account of the methods and techniques of vector analysis. These methods are indispensable tools in mathematics, physics, and engineering. The book is based on lectures given by the author in the University of Ceylon.The first two chapters deal with vector algebra. These chapters particularly present the addition, representation, and resolution of vectors. The next two chapters examine the various aspects and specificities of vector calculus. The last chapter looks into some standard applications of vector algebra and calculus.This book wil
Chen, Kan; Liu, Xiang; Matsuki, Takayuki
2015-01-01
Inspired by the abundant experimental observation of axial vector states, we study whether the observed axial vector states can be categorized into the conventional axial vector meson family. In this paper we carry out analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial vector mesons, which are valuable to further experimental exploration of the observed and predicted axial vector mesons.
U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...
Institute of Scientific and Technical Information of China (English)
Zhuo CHEN; Zhang Ju LIU; Yun He SHENG
2014-01-01
In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.
Chen, Zhuo; Liu, Zhangju; Sheng, Yunhe
2011-01-01
In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.
DEFF Research Database (Denmark)
Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan;
2015-01-01
We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum...
DEFF Research Database (Denmark)
Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan
2015-01-01
We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum...
Vector Magnetic Field Measurement of NOAA AR 10197
Institute of Scientific and Technical Information of China (English)
Hong-Fei Liang; Hai-Juan Zhao; Fu-Yuan Xiang
2006-01-01
A set of two-dimensional Stokes spectral data of NOAA AR 10197 obtained by the Solar Stokes Spectral Telescope (S3T) at the Yunnan Observatory are qualitatively analyzed.The three components of the vector magnetic field, the strength H, inclination γ and azimuth x, are derived. Based on the three components, we contour the distributions of the longitudinal magnetic field and transverse magnetic field. The active region (AR) has two different magnetic polarities apparent in the longitudinal magnetic map due to projection effect. There is a basic agreement on the longitudinal magnetic fields between the S3T and SOHO/MDI magnetograms, with a correlation coefficient ρBl = 0.911. The transverse magnetic field of the AR has a radial distribution from a center located in the southwest of the AR. It is also found that the transverse magnetic fields obtained by Huairou Solar Observing Station (HRSOS) have a similar radial distribution. The distributions of transverse magnetic field obtained by S3T and HRSOS have correlation coefficients, ρAzimu = 0.86 and ρBt = 0.883,in regard to the azimuthal angle and intensity.
Hayashi, K.; Hoeksema, J. T.; Liu, Y.; Bobra, M. G.; Sun, X. D.; Norton, A. A.
2015-05-01
Time-dependent three-dimensional magnetohydrodynamics (MHD) simulation modules are implemented at the Joint Science Operation Center (JSOC) of the Solar Dynamics Observatory (SDO). The modules regularly produce three-dimensional data of the time-relaxed minimum-energy state of the solar corona using global solar-surface magnetic-field maps created from Helioseismic and Magnetic Imager (HMI) full-disk magnetogram data. With the assumption of a polytropic gas with specific-heat ratio of 1.05, three types of simulation products are currently generated: i) simulation data with medium spatial resolution using the definitive calibrated synoptic map of the magnetic field with a cadence of one Carrington rotation, ii) data with low spatial resolution using the definitive version of the synchronic frame format of the magnetic field, with a cadence of one day, and iii) low-resolution data using near-real-time (NRT) synchronic format of the magnetic field on a daily basis. The MHD data available in the JSOC database are three-dimensional, covering heliocentric distances from 1.025 to 4.975 solar radii, and contain all eight MHD variables: the plasma density, temperature, and three components of motion velocity, and three components of the magnetic field. This article describes details of the MHD simulations as well as the production of the input magnetic-field maps, and details of the products available at the JSOC database interface. To assess the merits and limits of the model, we show the simulated data in early 2011 and compare with the actual coronal features observed by the Atmospheric Imaging Assembly (AIA) and the near-Earth in-situ data.
Hayashi, K; Hoeksema, J T; Liu, Y; Bobra, M G; Sun, X D; Norton, A A
Time-dependent three-dimensional magnetohydrodynamics (MHD) simulation modules are implemented at the Joint Science Operation Center (JSOC) of the Solar Dynamics Observatory (SDO). The modules regularly produce three-dimensional data of the time-relaxed minimum-energy state of the solar corona using global solar-surface magnetic-field maps created from Helioseismic and Magnetic Imager (HMI) full-disk magnetogram data. With the assumption of a polytropic gas with specific-heat ratio of 1.05, three types of simulation products are currently generated: i) simulation data with medium spatial resolution using the definitive calibrated synoptic map of the magnetic field with a cadence of one Carrington rotation, ii) data with low spatial resolution using the definitive version of the synchronic frame format of the magnetic field, with a cadence of one day, and iii) low-resolution data using near-real-time (NRT) synchronic format of the magnetic field on a daily basis. The MHD data available in the JSOC database are three-dimensional, covering heliocentric distances from 1.025 to 4.975 solar radii, and contain all eight MHD variables: the plasma density, temperature, and three components of motion velocity, and three components of the magnetic field. This article describes details of the MHD simulations as well as the production of the input magnetic-field maps, and details of the products available at the JSOC database interface. To assess the merits and limits of the model, we show the simulated data in early 2011 and compare with the actual coronal features observed by the Atmospheric Imaging Assembly (AIA) and the near-Earth in-situ data.
SOLIS/VSM Polar Magnetic Field Data
Bertello, Luca
2015-01-01
The Vector Spectromagnetograph (VSM) instrument on the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope is designed to obtain high-quality magnetic field observations in both the photosphere and chromosphere by measuring the Zeeman-induced polarization of spectral lines. With 1$^{\\prime \\prime}$ spatial resolution (1.14$^{\\prime \\prime}$ before 2010) and 0.05\\AA\\ spectral resolution, the VSM provides, among other products, chromospheric full-disk magnetograms using the CaII 854.2 nm spectral line and both photospheric full-disk vector and longitudinal magnetograms using the FeI 630.15 nm line. Here we describe the procedure used to compute daily weighted averages of the photospheric radial polar magnetic field at different latitude bands from SOLIS/VSM longitudinal full-disk observations. Time series of these measurements are publicly available from the SOLIS website at http://solis.nso.edu/0/vsm/vsm\\_plrfield.html. Future plans include the calculation of the mean polar field strength fr...
Zhang, Han
2011-01-01
Solitons, as stable localized wave packets that can propagate long distance in dispersive media without changing their shapes, are ubiquitous in nonlinear physical systems. Since the first experimental realization of optical bright solitons in the anomalous dispersion single mode fibers (SMF) by Mollenauer et al. in 1980 and optical dark solitons in the normal dispersion SMFs by P. Emplit et al. in 1987, optical solitons in SMFs had been extensively investigated. In reality a SMF always supports two orthogonal polarization modes. Taking fiber birefringence into account, it was later theoretically predicted that various types of vector solitons, including the bright-bright vector solitons, dark-dark vector solitons and dark-bright vector solitons, could be formed in SMFs. However, except the bright-bright type of vector solitons, other types of vector solitons are so far lack of clear experimental evidence. Optical solitons have been observed not only in the SMFs but also in mode locked fiber lasers. It has be...
2015-09-28
300001 1 of 16 VEHICLE-BASED VECTOR SENSOR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...unmanned underwater vehicle that can function as an acoustic vector sensor . (2) Description of the Prior Art [0004] It is known that a propagating...mechanics. An acoustic vector sensor measures the particle motion via an accelerometer and combines Attorney Docket No. 300001 2 of 16 the
Directory of Open Access Journals (Sweden)
Jean-François Degbomont
2010-10-01
Full Text Available This paper addresses the symbolic representation of non-convex real polyhedra, i.e., sets of real vectors satisfying arbitrary Boolean combinations of linear constraints. We develop an original data structure for representing such sets, based on an implicit and concise encoding of a known structure, the Real Vector Automaton. The resulting formalism provides a canonical representation of polyhedra, is closed under Boolean operators, and admits an efficient decision procedure for testing the membership of a vector.
Vectors and their applications
Pettofrezzo, Anthony J
2005-01-01
Geared toward undergraduate students, this text illustrates the use of vectors as a mathematical tool in plane synthetic geometry, plane and spherical trigonometry, and analytic geometry of two- and three-dimensional space. Its rigorous development includes a complete treatment of the algebra of vectors in the first two chapters.Among the text's outstanding features are numbered definitions and theorems in the development of vector algebra, which appear in italics for easy reference. Most of the theorems include proofs, and coordinate position vectors receive an in-depth treatment. Key concept
Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
Dias, Kealey
vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...
Advancing vector biology research
Kohl, Alain; Pondeville, Emilie; Schnettler, Esther; Crisanti, Andrea; Supparo, Clelia; Christophides, George K.; Kersey, Paul J.; Maslen, Gareth L.; Takken, Willem; Koenraadt, Constantianus J.M.; Oliva, Clelia F.; Busquets, Núria; Abad, F.X.; Failloux, Anna Bella; Levashina, Elena A.; Wilson, Anthony J.; Veronesi, Eva; Pichard, Maëlle; Arnaud Marsh, Sarah; Simard, Frédéric; Vernick, Kenneth D.
2016-01-01
Vector-borne pathogens impact public health, animal production, and animal welfare. Research on arthropod vectors such as mosquitoes, ticks, sandflies, and midges which transmit pathogens to humans and economically important animals is crucial for development of new control measures that target t
Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
Dias, Kealey
or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields....
Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields....
Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
Dias, Kealey
The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...
Georgoulis, Manolis K
2011-01-01
In a recent paper, Leka at al. (Solar Phys. 260, 83, 2009)constructed a synthetic vector magnetogram representing a three-dimensional magnetic structure defined only within a fraction of an arcsec in height. They rebinned the magnetogram to simulate conditions of limited spatial resolution and then compared the results of various azimuth disambiguation methods on the resampled data. Methods relying on the physical calculation of potential and/or non-potential magnetic fields failed in nearly the same, extended parts of the field of view and Leka et al. (2009) attributed these failures to the limited spatial resolution. This study shows that the failure of these methods is not due to the limited spatial resolution but due to the narrowly defined test data. Such narrow magnetic structures are not realistic in the real Sun. Physics-based disambiguation methods, adapted for solar magnetic fields extending to infinity, are not designed to handle such data; hence, they could only fail this test. I demonstrate how a...
ON VECTOR NETWORK EQUILIBRIUM PROBLEMS
Institute of Scientific and Technical Information of China (English)
Guangya CHEN
2005-01-01
In this paper we define a concept of weak equilibrium for vector network equilibrium problems.We obtain sufficient conditions of weak equilibrium points and establish relation with vector network equilibrium problems and vector variational inequalities.
Kosower, David A.
1993-01-01
In gauge theories with slowly-running coupling constants, it may be possible for four-fermion operators to be nearly marginal. Such operators can possess asymptotically weak couplings, and can plausibly give rise to light composite vector mesons.
Minnesota Department of Natural Resources — This vector dataset is a detailed (1-acre minimum), hierarchically organized vegetation cover map produced by computer classification of combined two-season pairs of...
Kansas Data Access and Support Center — The Kansas Tagged Vector Contour (TVC) dataset consists of digitized contours from the 7.5 minute topographic quadrangle maps. Coverage for the state is incomplete....
Vector Lattice Vortex Solitons
Institute of Scientific and Technical Information of China (English)
WANG Jian-Dong; YE Fang-Wei; DONG Liang-Wei; LI Yong-Ping
2005-01-01
@@ Two-dimensional vector vortex solitons in harmonic optical lattices are investigated. The stability properties of such solitons are closely connected to the lattice depth Vo. For small Vo, vector vortex solitons with the total zero-angular momentum are more stable than those with the total nonzero-angular momentum, while for large Vo, this case is inversed. If Vo is large enough, both the types of such solitons are stable.
Support vector machines applications
Guo, Guodong
2014-01-01
Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.
Magnetic vector rotation in response to the energetic electron beam during a flare
Xu, Yan; Cao, Wenda; Kwangsu, Ahn; Jing, Ju; Liu, Chang; Chae, Jongchul; Huang, Nengyi; Deng, Na; Gary, Dale E.; Wang, Haimin
2017-08-01
As one of the most violent forms of eruption on the Sun, flares are believed to be powered by magnetic reconnection, by which stored magnetic energy is released. The fundamental physical processes involving the release, transfer and deposition of energy in multiple layers of the solar atmosphere have been studied extensively with significant progress. Taking advantage of recent developments in observing facilities, new phenomena are continually revealed, bringing new understanding of solar flares. Here we report the discovery of a transient rotation of vector magnetic fields associated with a flare observed by the 1.6-m New Solar Telescope at Big Bear Solar Observatory. After ruling out the possibility that the rotation is caused by line profile changes due to flare heating, our observation shows that the transverse field rotateded by about 12-20 degrees counterclockwise, and returned quickly to previous values after the flare ribbons swept through. More importantly, as a consequence of the rotation, the flare loops untwisted and became more potential. The vector magnetograms were obtained in the near infrared at 1560 nm, which is minimally affected by flare emission and no intensity profile change was detected. Therefore, we believe that these transient changes are real, and conclude the high energy electron beams play an crucial role in the field changes. A straightforward and instructive explanation is that the induced magnetic field of the electron beam superimposed on the pre-flare field leads to a transient rotation of the overall field.
Navarro, Andres A
2013-01-01
We analyze a massive vector field with a non-canonical kinetic term in the action, minimally coupled to gravity, where the mass and kinetic function of the vector field vary as functions of time during inflation. The vector field is introduced following the same idea of a scalar curvaton, which must not affect the inflationary dynamics since its energy density during inflation is negligible compared to the total energy density in the Universe. Using this hypothesis, the vector curvaton will be solely responsible for generating the primordial curvature perturbation \\zeta. We have found that the spectra of the vector field perturbations are scale-invariant in superhorizon scales due to the suitable choice of the time dependence of the kinetic function and the effective mass during inflation. The preferred direction, generated by the vector field, makes the spectrum of \\zeta depend on the wavevector, i.e. there exists statistical anisotropy in \\zeta. This is discussed principally in the case where the mass of th...
Vector cross product in n-dimensional vector space
Tian, Xiu-Lao; Yang, Chao; Hu, Yang; Tian, Chao
2013-01-01
The definition of vector cross product (VCP) introduced by Eckmann only exists in thethree- and the seven- dimensional vector space. In this paper, according to the orthogonal completeness, magnitude of basis vector cross product and all kinds of combinations of basis vector $\\hat{e}_i$, the generalized definition of VCP in the odd n-dimensional vector space is given by introducing a cross term $X_{AB}$. In addition, the definition is validated by reducing the generalization definition to the...
Extended Mixed Vector Equilibrium Problems
Directory of Open Access Journals (Sweden)
Mijanur Rahaman
2014-01-01
Full Text Available We study extended mixed vector equilibrium problems, namely, extended weak mixed vector equilibrium problem and extended strong mixed vector equilibrium problem in Hausdorff topological vector spaces. Using generalized KKM-Fan theorem (Ben-El-Mechaiekh et al.; 2005, some existence results for both problems are proved in noncompact domain.
Bunyavirus-vector interactions.
Beaty, B J; Bishop, D H
1988-06-01
Recent advances in the genetics and molecular biology of bunyaviruses have been applied to understanding bunyavirus-vector interactions. Such approaches have revealed which virus gene and gene products are important in establishing infections in vectors and in transmission of viruses. However, much more information is required to understand the molecular mechanisms of persistent infections of vectors which are lifelong but apparently exert no untoward effect. In fact, it seems remarkable that LAC viral antigen can be detected in almost every cell in an ovarian follicle, yet no untoward effect on fecundity and no teratology is seen. Similarly the lifelong infection of the vector would seem to provide ample opportunity for bunyavirus evolution by genetic drift and, under the appropriate circumstances, by segment reassortment. The potential for bunyavirus evolution by segment reassortment in vectors certainly exists. For example the Group C viruses in a small forest in Brazil seem to constitute a gene pool, with the 6 viruses related alternately by HI/NT and CF reactions, which assay respectively M RNA and S RNA gene products (Casals and Whitman, 1960; Shope and Causey, 1962). Direct evidence for naturally occurring reassortant bunyaviruses has also been obtained. Oligonucleotide fingerprint analyses of field isolates of LAC virus and members of the Patois serogroup of bunyaviruses have demonstrated that reassortment does occur in nature (El Said et al., 1979; Klimas et al., 1981; Ushijima et al., 1981). Determination of the genotypic frequencies of viruses selected by the biological interactions of viruses and vectors after dual infection and segment reassortment is an important issue. Should a virus result that efficiently interacts with alternate vector species, the virus could be expressed in different circumstances with serious epidemiologic consequences. Dual infection of vectors with different viruses is not unlikely, because many bunyaviruses are sympatric in
Barbarien, Joeri; Munteanu, Adrian; Verdicchio, Fabio; Andreopoulos, Yiannis; Cornelis, Jan P.; Schelkens, Peter
2004-11-01
Modern video coding applications require transmission of video data over variable-bandwidth channels to a variety of terminals with different screen resolutions and available computational power. Scalable video coding is needed to optimally support these applications. Recently proposed wavelet-based video codecs employing spatial domain motion compensated temporal filtering (SDMCTF) provide quality, resolution and frame-rate scalability while delivering compression performance comparable to that of the state-of-the-art non-scalable H.264-codec. These codecs require scalable coding of the motion vectors in order to support a large range of bit-rates with optimal compression efficiency. Scalable motion vector coding algorithms based on the integer wavelet transform followed by embedded coding of the wavelet coefficients were recently proposed. In this paper, a new and fundamentally different scalable motion vector codec (MVC) using median-based motion vector prediction is proposed. Extensive experimental results demonstrate that the proposed MVC systematically outperforms the wavelet-based state-of-the-art solutions. To be able to take advantage of the proposed scalable MVC, a rate allocation mechanism capable of optimally dividing the available rate among texture and motion information is required. Two rate allocation strategies are proposed and compared. The proposed MVC and rate allocation schemes are incorporated into an SDMCTF-based video codec and the benefits of scalable motion vector coding are experimentally demonstrated.
Vector Fields on Product Manifolds
Kurz, Stefan
2011-01-01
This short report establishes some basic properties of smooth vector fields on product manifolds. The main results are: (i) On a product manifold there always exists a direct sum decomposition into horizontal and vertical vector fields. (ii) Horizontal and vertical vector fields are naturally isomorphic to smooth families of vector fields defined on the factors. Vector fields are regarded as derivations of the algebra of smooth functions.
Robustifying Vector Median Filter
Directory of Open Access Journals (Sweden)
Valentín Gregori
2011-08-01
Full Text Available This paper describes two methods for impulse noise reduction in colour images that outperform the vector median filter from the noise reduction capability point of view. Both methods work by determining first the vector median in a given filtering window. Then, the use of complimentary information from componentwise analysis allows to build robust outputs from more reliable components. The correlation among the colour channels is taken into account in the processing and, as a result, a more robust filter able to process colour images without introducing colour artifacts is obtained. Experimental results show that the images filtered with the proposed method contain less noisy pixels than those obtained through the vector median filter. Objective measures demonstrate the goodness of the achieved improvement.
Boosting Support Vector Machines
Directory of Open Access Journals (Sweden)
Elkin Eduardo García Díaz
2006-11-01
Full Text Available En este artículo, se presenta un algoritmo de clasificación binaria basado en Support Vector Machines (Máquinas de Vectores de Soporte que combinado apropiadamente con técnicas de Boosting consigue un mejor desempeño en cuanto a tiempo de entrenamiento y conserva características similares de generalización con un modelo de igual complejidad pero de representación más compacta./ In this paper we present an algorithm of binary classification based on Support Vector Machines. It is combined with a modified Boosting algorithm. It run faster than the original SVM algorithm with a similar generalization error and equal complexity model but it has more compact representation.
Rejon-Barrera, Fernando
2015-01-01
We work out all of the details required for implementation of the conformal bootstrap program applied to the four-point function of two scalars and two vectors in an abstract conformal field theory in arbitrary dimension. This includes a review of which tensor structures make appearances, a construction of the projectors onto the required mixed symmetry representations, and a computation of the conformal blocks for all possible operators which can be exchanged. These blocks are presented as differential operators acting upon the previously known scalar conformal blocks. Finally, we set up the bootstrap equations which implement crossing symmetry. Special attention is given to the case of conserved vectors, where several simplifications occur.
Energy Technology Data Exchange (ETDEWEB)
Rejon-Barrera, Fernando [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, Postbus 94485, 1090 GL, Amsterdam (Netherlands); Robbins, Daniel [Department of Physics, Texas A& M University,TAMU 4242, College Station, TX 77843 (United States)
2016-01-22
We work out all of the details required for implementation of the conformal bootstrap program applied to the four-point function of two scalars and two vectors in an abstract conformal field theory in arbitrary dimension. This includes a review of which tensor structures make appearances, a construction of the projectors onto the required mixed symmetry representations, and a computation of the conformal blocks for all possible operators which can be exchanged. These blocks are presented as differential operators acting upon the previously known scalar conformal blocks. Finally, we set up the bootstrap equations which implement crossing symmetry. Special attention is given to the case of conserved vectors, where several simplifications occur.
Narici, Lawrence
2011-01-01
BackgroundTopology Valuation Theory Algebra Linear Functionals Hyperplanes Measure Theory Normed SpacesCommutative Topological GroupsElementary ConsiderationsSeparation and Compactness Bases at 0 for Group Topologies Subgroups and Products Quotients S-Topologies Metrizability CompletenessCompleteness Function Groups Total BoundednessCompactness and Total Boundedness Uniform Continuity Extension of Uniformly Continuous Maps CompletionTopological Vector SpacesAbsorbent and Balanced Sets Convexity-AlgebraicBasic PropertiesConvexity-Topological Generating Vector Topologies A Non-Locally Convex Spa
Eisenman, Richard L
2005-01-01
This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur
Free topological vector spaces
Gabriyelyan, Saak S.; Morris, Sidney A.
2016-01-01
We define and study the free topological vector space $\\mathbb{V}(X)$ over a Tychonoff space $X$. We prove that $\\mathbb{V}(X)$ is a $k_\\omega$-space if and only if $X$ is a $k_\\omega$-space. If $X$ is infinite, then $\\mathbb{V}(X)$ contains a closed vector subspace which is topologically isomorphic to $\\mathbb{V}(\\mathbb{N})$. It is proved that if $X$ is a $k$-space, then $\\mathbb{V}(X)$ is locally convex if and only if $X$ is discrete and countable. If $X$ is a metrizable space it is shown ...
Duality in vector optimization
Bot, Radu Ioan
2009-01-01
This book presents fundamentals and comprehensive results regarding duality for scalar, vector and set-valued optimization problems in a general setting. After a preliminary chapter dedicated to convex analysis and minimality notions of sets with respect to partial orderings induced by convex cones a chapter on scalar conjugate duality follows. Then investigations on vector duality based on scalar conjugacy are made. Weak, strong and converse duality statements are delivered and connections to classical results from the literature are emphasized. One chapter is exclusively consecrated to the s
Akcoglu, Mustafa A; Ha, Dzung Minh
2011-01-01
A rigorous introduction to calculus in vector spaces The concepts and theorems of advanced calculus combined with related computational methods are essential to understanding nearly all areas of quantitative science. Analysis in Vector Spaces presents the central results of this classic subject through rigorous arguments, discussions, and examples. The book aims to cultivate not only knowledge of the major theoretical results, but also the geometric intuition needed for both mathematical problem-solving and modeling in the formal sciences. The authors begin with an outline of key concepts, ter
DEFF Research Database (Denmark)
2000-01-01
Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...
Dean, Richard A.
1971-01-01
The author shows that the set of all sequences in which each term is the sum of the two previous terms forms a vector space of dimension two. He uses this result to obtain the formula for the Fibonacci sequence and applies the same technique to other linear recursive relations. (MM)
Support Vector Components Analysis
van der Ree, Michiel; Roerdink, Johannes; Phillips, Christophe; Garraux, Gaetan; Salmon, Eric; Wiering, Marco
2017-01-01
In this paper we propose a novel method for learning a distance metric in the process of training Support Vector Machines (SVMs) with the radial basis function kernel. A transformation matrix is adapted in such a way that the SVM dual objective of a classification problem is optimized. By using a wi
Synthetic Space Vector Modulation
2013-06-01
Modulation RF Radio Frequency SVM Space Vector Modulation VCO Voltage Controlled Oscillator VSI Voltage Source Inverter xvi THIS PAGE...examining the literature, an NE566 voltage controlled oscillator ( VCO ) chip as seen in Figure 10 was used to design a circuit that produced the
Production of lentiviral vectors
Directory of Open Access Journals (Sweden)
Otto-Wilhelm Merten
2016-01-01
Full Text Available Lentiviral vectors (LV have seen considerably increase in use as gene therapy vectors for the treatment of acquired and inherited diseases. This review presents the state of the art of the production of these vectors with particular emphasis on their large-scale production for clinical purposes. In contrast to oncoretroviral vectors, which are produced using stable producer cell lines, clinical-grade LV are in most of the cases produced by transient transfection of 293 or 293T cells grown in cell factories. However, more recent developments, also, tend to use hollow fiber reactor, suspension culture processes, and the implementation of stable producer cell lines. As is customary for the biotech industry, rather sophisticated downstream processing protocols have been established to remove any undesirable process-derived contaminant, such as plasmid or host cell DNA or host cell proteins. This review compares published large-scale production and purification processes of LV and presents their process performances. Furthermore, developments in the domain of stable cell lines and their way to the use of production vehicles of clinical material will be presented.
Centers for Disease Control (CDC) Podcasts
2011-04-18
This podcast discusses emerging vector-borne pathogens, their role as prominent contributors to emerging infectious diseases, how they're spread, and the ineffectiveness of mosquito control methods. Created: 4/18/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID). Date Released: 4/27/2011.
Wilson, Anthony James; Morgan, Eric René; Booth, Mark; Norman, Rachel; Perkins, Sarah Elizabeth; Hauffe, Heidi Christine; Mideo, Nicole; Antonovics, Janis; McCallum, Hamish; Fenton, Andy
2017-05-05
Many important and rapidly emerging pathogens of humans, livestock and wildlife are 'vector-borne'. However, the term 'vector' has been applied to diverse agents in a broad range of epidemiological systems. In this perspective, we briefly review some common definitions, identify the strengths and weaknesses of each and consider the functional differences between vectors and other hosts from a range of ecological, evolutionary and public health perspectives. We then consider how the use of designations can afford insights into our understanding of epidemiological and evolutionary processes that are not otherwise apparent. We conclude that from a medical and veterinary perspective, a combination of the 'haematophagous arthropod' and 'mobility' definitions is most useful because it offers important insights into contact structure and control and emphasizes the opportunities for pathogen shifts among taxonomically similar species with similar feeding modes and internal environments. From a population dynamics and evolutionary perspective, we suggest that a combination of the 'micropredator' and 'sequential' definition is most appropriate because it captures the key aspects of transmission biology and fitness consequences for the pathogen and vector itself. However, we explicitly recognize that the value of a definition always depends on the research question under study.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'. © 2017 The Authors.
Treiman, Jay S
2014-01-01
Calculus with Vectors grew out of a strong need for a beginning calculus textbook for undergraduates who intend to pursue careers in STEM. fields. The approach introduces vector-valued functions from the start, emphasizing the connections between one-variable and multi-variable calculus. The text includes early vectors and early transcendentals and includes a rigorous but informal approach to vectors. Examples and focused applications are well presented along with an abundance of motivating exercises. All three-dimensional graphs have rotatable versions included as extra source materials and may be freely downloaded and manipulated with Maple Player; a free Maple Player App is available for the iPad on iTunes. The approaches taken to topics such as the derivation of the derivatives of sine and cosine, the approach to limits, and the use of "tables" of integration have been modified from the standards seen in other textbooks in order to maximize the ease with which students may comprehend the material. Additio...
DEFF Research Database (Denmark)
2000-01-01
Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...
VECTOR BUNDLE, KILLING VECTOR FIELD AND PONTRYAGIN NUMBERS
Institute of Scientific and Technical Information of China (English)
周建伟
1991-01-01
Let E be a vector bundle over a compact Riemannian manifold M. We construct a natural metric on the bundle space E and discuss the relationship between the killing vector fields of E and M. Then we give a proof of the Bott-Baum-Cheeger Theorem for vector bundle E.
Current helicity pattern of large-scale magnetic field on the photosphere
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Following Pevtsov and Latushko, we study the current helicity pattern of the large-scale magnetic field on the photosphere. We use the same technique as theirs to derive the vector magnetic field (Br,Bθ,Bφ) from full-disk longitudinal magnetograms based on the assumption that large-scale magnetic fields evolve rather slowly and the variations of the longitudinal magnetic fields within certain time duration are caused by the changing position angles only. Different from their study, we have calculated the current helicity maps directly from the derived vector magnetograms, rather than from obtaining the latitudinal variation of hc by ignoring the role of Bθ component and averaging Br and Bφ over all solar longitudes. This approach significantly strengthens the evidence of the hemispheric rule presented in the reconstructed vector magnetic field. Our study shows that the established hemispheric sign rule, that is, positive helicity sign in the southern hemisphere and negative helicity sign in the northern hemisphere, is applicable everywhere in the global magnetic field, namely, also evident in weak fields outside active regions, and that the obtained sign pattern is independent of the longitudinal magnetograms and the parameters that we have used.
On Generalized Vector Equilibrium Problems
Institute of Scientific and Technical Information of China (English)
An-hua Wan; Jun-yi Fu; Wei-hua Mao
2006-01-01
A new generalized vector equilibrium problem involving set-valued mappings and the proper quasi-concavity of set-valued mappings in topological vector spaces are introduced; its existence theorems and the convexity of the solution sets are established.
Vector grammars and PN machines
Institute of Scientific and Technical Information of China (English)
蒋昌俊
1996-01-01
The concept of vector grammars under the string semantic is introduced.The dass of vector grammars is given,which is similar to the dass of Chomsky grammars.The regular vector grammar is divided further.The strong and weak relation between the vector grammar and scalar grammar is discussed,so the spectrum system graph of scalar and vector grammars is made.The equivalent relation between the regular vector grammar and Petri nets (also called PN machine) is pointed.The hybrid PN machine is introduced,and its language is proved equivalent to the language of the context-free vector grammar.So the perfect relation structure between vector grammars and PN machines is formed.
High Cadence Digital Full Disk Hα Patrol Device at Kanzelhöhe
Otruba, W.
1999-09-01
The need for monitoring the sun in the prominent Hα-line is evident. For a long time this recording was done on photographic film at Kanzelhöhe Solar Observatory. Now with the evolution of CCDs and digital mass storage devices it is possible and even more economical to do this job digitally. A 1kx1k CCD camera and a standard frame grabbing system on a conventional PC are attached to the established Kanzelhöhe Patrol Instrument with a narrow band Hα filter. At the present state a very simple frame selection mechanism is installed to improve the image quality. The data are archived on CDs. The development of a standard image processing and evaluation system is in progress. Low cadence synoptic images are currently fed into the SOHO synoptic database. Instant data access from the Kanzelhöhe database via WWW is planned.
Revised Full-Disk Spectra by Cassini-VIMS of the Saturnian Minor Icy Moons
Filacchione, G.; Cuzzi, J. N.; Clark, R. N.; Buratti, B. J.; Capaccioni, F.; Tosi, F.; Coradini, A.; Cerroni, P.; Adriani, A.; Cruikshank, D. P.; Jaumann, R.; Stephan, K.; Brown, R. H.; Nicholson, P. D.; Baines, K. H.; Nelson, R. M.; McCord, T. B.
2009-03-01
This abstract concern with a detailed re-analysis of the disk-integrated spectra of the minor moons of Saturn (Atlas, Prometheus, Pandora, Janus, Epimetheus, Calypso and Telesto) obtained by Cassini-VIMS.
Indian Academy of Sciences (India)
Gy Wolf
2006-04-01
One consequence of the chiral restoration is the mixing of parity partners. We look for a possible signature of the mixing of vector and axial vector mesons in heavy-ion collisions. We suggest an experimental method for its observation. The dynamical evolution of the heavy-ion collision is described by a transport equation of QMD-type evolving nucleons, * and resonances, ’s and $\\sum$ baryons, and furthermore, ’s, ’s ’s ’s ’s and kaons with their isospin degrees of freedom. The input cross-sections and resonance parameters of the model are fitted to the available nucleon–nucleon and pion–nucleon cross-sections.
Davydov, Evgeny
2011-01-01
Vector fields can arise in the cosmological context in different ways, and we discuss both abelian and nonabelian sector. In the abelian sector vector fields of the geometrical origin (from dimensional reduction and Einstein-Eddington modification of gravity) can provide a very non-trivial dynamics, which can be expressed in terms of the effective dilaton-scalar gravity with the specific potential. In the non-abelian sector we investigate the Yang-Mills SU(2) theory which admits isotropic and homogeneous configuration. Provided the non-linear dependence of the lagrangian on the invariant F*F(dual), one can obtain the inflationary regime with the exponential growth of the scale factor. The effective amplitudes of the 'electric' and 'magnetic' components behave like slowly varying scalars at this regime, what allows the consideration of some realistic models with non-linear terms in the Yang-Mills lagrangian.
Rudakov, A N
1990-01-01
This volume is devoted to the use of helices as a method for studying exceptional vector bundles, an important and natural concept in algebraic geometry. The work arises out of a series of seminars organised in Moscow by A. N. Rudakov. The first article sets up the general machinery, and later ones explore its use in various contexts. As to be expected, the approach is concrete; the theory is considered for quadrics, ruled surfaces, K3 surfaces and P3(C).
Decay Constants of Vector Mesons
Institute of Scientific and Technical Information of China (English)
LI Heng-Mei; WAN Shao-Long
2008-01-01
@@ The light vector mesons are studied within the framework of the Bethe-Salpeter equation with the vector-vectortype flat-bottom potential The Bethe-Salpeter wavefunctions and the decay constants of the vector mesons are obtained. All the obtained results, fρ, fφ, and fΚ* , are in agreement with the experimental values, respectively.
Student Preconceptions about Vector Kinematics.
Aguirre, Jose M.
1988-01-01
Examines preconceptions regarding several implicit vector characteristics that 15- to 17-year-old students possess just before taking their first physics course. Shows seven vector characteristics and three tasks for interviewing students. Presents the most common student preconceptions regarding each of the implicit vector characteristics. (YP)
Interpolation of Vector Measures
Institute of Scientific and Technical Information of China (English)
Ricardo del CAMPO; Antonio FERN(A)NDEZ; Fernando MAYORAL; Francisco NARANJO; Enrique A. S(A)NCHEZ-P(E)REZ
2011-01-01
Let (Ω, ∑) be a measurable space and m0: ∑→ X0 and m1: ∑ -→ X1 be positive vector measures with values in the Banach K(o)the function spaces X0 and X1. If 0 < α < 1, we define a X10-αXα1 and we analyze the space of integrable functions with respect to measure [m0, m1]α in order to prove suitable extensions of the classical Stein-Weiss formulas that hold for the complex interpolation of Lp-spaces.Since each p-convex order continuous K(o)the function space with weak order unit can be represented as a space of p-integrable functions with respect to a vector measure, we provide in this way a technique to obtain representations of the corresponding complex interpolation spaces. As applications, we provide a Riesz-Thorin theorem for spaces of p-integrable functions with respect to vector measures and a formula for representing the interpolation of the injective tensor product of such spaces.
1992-01-01
El texto Números, Vectores y Funciones que han elaborado los profesores Asociados Omar Evelio Ospina y Bernardo Acevedo, responden a esta necesidad con sobresalientes cualidades pedagógicas, entre las cuales se destacan el desarrollo detallado de los temas y la proliferación de ejercicios resueltos, lo cual genera un diálogo directo con el lector que puede así aprovechar totalmente su lectura. El material presentado es el fruto de un cuidadoso análisis de los autores, sobre las experiencias d...
Energy Technology Data Exchange (ETDEWEB)
Nillius, Fabian; Aulenbacher, Kurt [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)
2013-07-01
Electron/photon tensor-correlation coefficients may allow to design a polarimeter that can measure all components of beam polarisation simultaneously (''vector polarimeter''). Besides its purpose as a beam diagnostic device this would also allow to test theoretical predictions for the correlation coefficients at energies between 1 and 3.5 MeV. As a first step we have set up a measurement of the helicity transfer to the photon as a function of energy which is based on the Compton absorption method. Apparative developments in order to measure photon emission asymmetries caused by transverse and longitudinal electron polarisation are presented.
DEFF Research Database (Denmark)
More, Simon J.; Bicout, Dominique; Bøtner, Anette
2017-01-01
After a request from the Europea n Commission, EFSA’s Panel on Animal Health and Welfaresummarised the main characteristics of 36 vector-borne disease s (VBDs) in 36 web-based storymaps.The risk of introduction in the EU through movement of livestock or pets was assessed for eac h of the36 VBDs...... new information becomesavailable. Since this risk assessment was carried out for large regions in the EU for many VBD-agents,it should be considered as a ﬁrst screening. If a more detailed risk assessment for a speciﬁcVBDiswished for on a national or subnational level, the EFSA...
Relativistic Rotating Vector Model
Lyutikov, Maxim
2016-01-01
The direction of polarization produced by a moving source rotates with the respect to the rest frame. We show that this effect, induced by pulsar rotation, leads to an important correction to polarization swings within the framework of rotating vector model (RVM); this effect has been missed by previous works. We construct relativistic RVM taking into account finite heights of the emission region that lead to aberration, time-of-travel effects and relativistic rotation of polarization. Polarizations swings at different frequencies can be used, within the assumption of the radius-to-frequency mapping, to infer emission radii and geometry of pulsars.
Vector potential photoelectron microscopy.
Browning, R
2011-10-01
A new class of electron microscope has been developed for the chemical microanalysis of a wide range of real world samples using photoelectron spectroscopy. Highly structured, three-dimensional samples, such as fiber mats and fracture surfaces can be imaged, as well as insulators and magnetic materials. The new microscope uses the vector potential field from a solenoid magnet as a spatial reference for imaging. A prototype instrument has demonstrated imaging of uncoated silk, magnetic steel wool, and micron-sized single strand tungsten wires.
Extended vector-tensor theories
Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke
2017-01-01
Recently, several extensions of massive vector theory in curved space-time have been proposed in many literatures. In this paper, we consider the most general vector-tensor theories that contain up to two derivatives with respect to metric and vector field. By imposing a degeneracy condition of the Lagrangian in the context of ADM decomposition of space-time to eliminate an unwanted mode, we construct a new class of massive vector theories where five degrees of freedom can propagate, corresponding to three for massive vector modes and two for massless tensor modes. We find that the generalized Proca and the beyond generalized Proca theories up to the quartic Lagrangian, which should be included in this formulation, are degenerate theories even in curved space-time. Finally, introducing new metric and vector field transformations, we investigate the properties of thus obtained theories under such transformations.
Semitopological Vector Spaces and Hyperseminorms
Directory of Open Access Journals (Sweden)
Mark Burgin
2013-11-01
Full Text Available In this paper, we introduce and study semitopological vector spaces. The goal is to provide an efficient base for developing the theory of extrafunction spaces in an abstract setting of algebraic systems and topological spaces. Semitopological vector spaces are more general than conventional topological vector spaces, which proved to be very useful for solving many problems in functional analysis. To study semitopological vector spaces, hypermetrics and hyperpseudometrics are introduced and it is demonstrated that hyperseminorms, studied in previous works of the author, induce hyperpseudometrics, while hypernorms induce hypermetrics. Sufficient and necessary conditions for a hyperpseudometric (hypermetric to be induced by a hyperseminorm (hypernorm are found. We also show that semitopological vector spaces are closely related to systems of hyperseminorms. Then defining boundedness and continuity relative to associated systems of hyperseminorms, we study relations between relative boundedness and relative continuity for mappings of vector spaces with systems of hyperseminorms and systems of hypernorms.
Safety considerations in vector development.
Kappes, J C; Wu, X
2001-11-01
The inadvertent production of replication competent retrovirus (RCR) constitutes the principal safety concern for the use of lentiviral vectors in human clinical protocols. Because of limitations in animal models to evaluate lentiviral vectors for their potential to recombine and induce disease, the vector design itself should ensure against the emergence of RCR in vivo. Issues related to RCR generation and one approach to dealing with this problem are discussed in this chapter. To assess the risk of generating RCR, a highly sensitive biological assay was developed to specifically detect vector recombination in transduced cells. Analysis of lentiviral vector stocks has shown that recombination occurs during reverse transcription in primary target cells. Rejoining of viral protein-coding sequences of the packaging construct and cis-acting sequences of the vector was demonstrated to generate env-minus recombinants (LTR-gag-pol-LTR). Mobilization of recombinant lentiviral genomes was also demonstrated but was dependent on pseudotyping of the vector core with an exogenous envelope protein. 5' sequence analysis has demonstrated that recombinants consist of U3, R, U5, and the psi packaging signal joined with an open gag coding region. Analysis of the 3' end has mapped the point of vector recombination to the poly(A) tract of the packaging construct's mRNA. The state-of-the-art third generation packaging construct and SIN vector also have been shown to generate env-minus proviral recombinants capable of mobilizing retroviral DNA when pseudotyped with an exogenous envelope protein. A new class of HIV-based vector (trans-vector) was recently developed that splits the gag-pol component of the packaging construct into two parts: one that expresses Gag/Gag-Pro and another that expresses Pol (RT and IN) fused with Vpr. Unlike other lentiviral vectors, the trans-vector has not been shown to form recombinants capable of DNA mobilization. These results indicate the trans-vector
VLSI Processor For Vector Quantization
Tawel, Raoul
1995-01-01
Pixel intensities in each kernel compared simultaneously with all code vectors. Prototype high-performance, low-power, very-large-scale integrated (VLSI) circuit designed to perform compression of image data by vector-quantization method. Contains relatively simple analog computational cells operating on direct or buffered outputs of photodetectors grouped into blocks in imaging array, yielding vector-quantization code word for each such block in sequence. Scheme exploits parallel-processing nature of vector-quantization architecture, with consequent increase in speed.
Buchin, Kevin; Moser, Robin A; Pálvölgyi, Dömötör
2009-01-01
For an integer d>=1, let tau(d) be the smallest integer with the following property: If v1,v2,...,vt is a sequence of t>=2 vectors in [-1,1]^d with v1+v2+...+vt in [-1,1]^d, then there is a subset S of {1,2,...,t} of indices, 2= d^{d/2-o(d)}. These results contribute to understanding the master equality polyhedron with multiple rows defined by Dash et al., which is a "universal" polyhedron encoding valid cutting planes for integer programs (this line of research was started by Gomory in the late 1960s). In particular, the upper bound on tau(d) implies a pseudo-polynomial running time for an algorithm of Dash et al. for integer programming with a fixed number of constraints. The algorithm consists in solving a linear program, and it provides an alternative to a 1981 dynamic programming algorithm of Papadimitriou.
D'Ambrosio, Vincenzo; Carvacho, Gonzalo; Graffitti, Francesco; Vitelli, Chiara; Piccirillo, Bruno; Marrucci, Lorenzo; Sciarrino, Fabio
2016-09-01
Light beams having a vectorial field structure, or polarization, that varies over the transverse profile and a central optical singularity are called vector vortex (VV) beams and may exhibit specific properties such as focusing into "light needles" or rotation invariance. VV beams have already found applications in areas ranging from microscopy to metrology, optical trapping, nano-optics, and quantum communication. Individual photons in such beams exhibit a form of single-particle quantum entanglement between different degrees of freedom. On the other hand, the quantum states of two photons can be also entangled with each other. Here, we combine these two concepts and demonstrate the generation of quantum entanglement between two photons that are both in VV states: a form of entanglement between two complex vectorial fields. This result may lead to quantum-enhanced applications of VV beams as well as to quantum information protocols fully exploiting the vectorial features of light.
Solar imaging vector magnetograph
Canfield, Richard C.
1993-01-01
This report describes an instrument which has been constructed at the University of Hawaii to make observations of the magnetic field in solar active regions. Detailed knowledge of active region magnetic structures is crucial to understanding many solar phenomena, because the magnetic field both defines the morphology of structures seen in the solar atmosphere and is the apparent energy source for solar flares. The new vector magnetograph was conceived in response to a perceived discrepancy between the capabilities of X ray imaging telescopes to be operating during the current solar maximum and those of existing magnetographs. There were no space-based magnetographs planned for this period; the existing ground-based instruments variously suffered from lack of sensitivity, poor time resolution, inadequate spatial resolution or unreliable sites. Yet the studies of flares and their relationship to the solar corona planned for the 1991-1994 maximum absolutely required high quality vector magnetic field measurements. By 'vector' measurements we mean that the observation attempts to deduce the complete strength and direction of the field at the measurement site, rather than just the line of sight component as obtained by a traditional longitudinal magnetograph. Knowledge of the vector field permits one to calculate photospheric electric currents, which might play a part in heating the corona, and to calculate energy stored in coronal magnetic fields as the result of such currents. Information about the strength and direction of magnetic fields in the solar atmosphere can be obtained in a number of ways, but quantitative data is best obtained by observing Zeeman-effect polarization in solar spectral lines. The technique requires measuring the complete state of polarization at one or more wavelengths within a magnetically sensitive line of the solar spectrum. This measurement must be done for each independent spatial point for which one wants magnetic field data. All the
Kolpakov, Stanislav A; Loika, Yuri; Tarasov, Nikita; Kalashnikov, Vladimir; Agrawal, Govind P
2015-01-01
A mode locked fibre laser as a source of ultra-stable pulse train has revolutionised a wide range of fundamental and applied research areas by offering high peak powers, high repetition rates, femtosecond range pulse widths and a narrow linewidth. However, further progress in linewidth narrowing seems to be limited by the complexity of the carrier-envelope phase control. Here for the first time we demonstrate experimentally and theoretically a new mechanism of resonance vector self-mode locking where tuning in-cavity birefringence leads to excitation of the longitudinal modes sidebands accompanied by the resonance phase locking of sidebands with the adjacent longitudinal modes. An additional resonance with acoustic phonons provides the repetition rate tunability and linewidth narrowing down to Hz range that drastically reduces the complexity of the carrier-envelope phase control and so will open the way to advance lasers in the context of applications in metrology, spectroscopy, microwave photonics, astronomy...
Vector-Tensor and Vector-Vector Decay Amplitude Analysis of B0->phi K*0
Aubert, B; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, R; Allen, M T; Allison, J; Altenburg, D D; Andreotti, M; Angelini, C; Anulli, F; Arnaud, N; Asgeirsson, D J; Aston, D; Azzolini, V; Baak, M A; Back, J J; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Bard, D J; Barlow, N R; Barlow, R J; Barrett, M; Bartoldus, R; Batignani, G; Battaglia, M; Bauer, J M; Bechtle, P; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Benelli, G; Berger, N; Bernard, D; Berryhill, J W; Best, D S; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bhuyan, B; Bianchi, F; Biasini, M; Biesiada, J; Blanc, F; Blaylock, G; Blinov, V E; Bloom, P C; Blount, N L; Bomben, M; Bondioli, M; Bonneaud, G R; Bosisio, L; Boutigny, D; Bowerman, D A; Boyd, J T; Bozzi, C; Brandenburg, G; Brandt, T; Brau, J E; Briand, H; Brown, C M; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Bugg, W; Bukin, A D; Bula, R; Burchat, P R; Burke, J P; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Cenci, R; Chai, X; Chaisanguanthum, K S; Chao, M; Charles, E; Charles, M J; Chauveau, J; Chavez, C A; Chen, A; Chen, C; Chen, E; Chen, J C; Chen, S; Chen, X; Chen, X R; Cheng, B; Cheng, C H; Chia, Y M; Cibinetto, G; Clark, P J; Clarke, C K; Claus, R; Cochran, J; Coleman, J P; Contri, R; Convery, M R; Corwin, L A; Cossutti, F; Cottingham, W N; Couderc, F; Covarelli, R; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L; Cunha, A; Curry, S; Côté, D; D'Orazio, A; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; De Nardo, Gallieno; De Sangro, R; Del Amo-Sánchez, P; Del Buono, L; Del Re, D; Della Ricca, G; Denig, A G; Di Lodovico, F; Di Marco, E; Dingfelder, J C; Dittongo, S; Dong, L; Dorfan, J; Druzhinin, V P; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Ebert, M; Eckhart, E A; Eckmann, R; Edgar, C L; Edwards, A J; Egede, U; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Eyges, V; Fabozzi, F; Faccini, R; Fang, F; Feltresi, E; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Flacco, C J; Flack, R L; Flächer, H U; Flood, K T; Ford, K E; Ford, W T; Forster, I J; Forti, F; Fortin, D; Foulkes, S D; Franek, B; Frey, R; Fritsch, M; Fry, J R; Fulsom, B G; Gabathuler, E; Gaidot, A; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gao, Y; Gary, J W; Gaspero, M; Gatto, C; Gaz, A; George, K A; Gill, M S; Giorgi, M A; Gladney, L; Glanzman, T; Godang, R; Golubev, V B; Gowdy, S J; Gradl, W; Graham, M T; Graugès-Pous, E; Grenier, P; Gritsan, A V; Grosdidier, G; Groysman, Y; Guo, Z J; Hadavand, H K; Haire, M; Halyo, V; Hamano, K; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, A J; Hartfiel, B L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hill, E J; Hirschauer, J F; Hitlin, D G; Hollar, J J; Hong, T M; Honscheid, K; Hopkins, D A; Hrynóva, T; Hufnagel, D; Hulsbergen, W D; Hutchcroft, D E; Höcker, A; Igonkina, O; Innes, W R; Izen, J M; Jackson, P D; Jackson, P S; Jacobsen, R G; Jain, V; Jasper, H; Jawahery, A; Jessop, C P; Judd, D; Kadyk, J A; Kagan, H; Karyotakis, Yu; Kass, R; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Klose, V; Knecht, N S; Koch, H; Kolb, J A; Kolomensky, Yu G; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kreisel, A; Krishnamurthy, M; Kroeger, R; Kroseberg, J; Kukartsev, G; Kutter, P E; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lanceri, L; Lange, D J; Lankford, A J; Latham, T E; Latour, E; Lau, Y P; Lazzaro, A; Le Diberder, F R; Lee, C L; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Lewandowski, B; Li Gioi, L; Li, S; Li, X; Lista, L; Liu, H; Lo Vetere, M; LoSecco, J M; Lockman, W S; Lombardo, V; Long, O; Lopes-Pegna, D; Lopez-March, N; Lou, X C; Lu, M; Luitz, S; Lund, P; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lü, C; Lüth, V; MacFarlane, D B; Macri, M M; Mader, W F; Majewski, S A; Malcles, J; Mallik, U; Mancinelli, G; Mandelkern, M A; Marchiori, G; Margoni, M; Marks, J; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mazur, M A; Mazzoni, M A; McKenna, J A; McMahon, T R; Mclachlin, S E; Meadows, B T; Mellado, B; Menges, W; Merkel, J; Messner, R; Meyer, N T; Meyer, W T; Mihályi, A; Mir, L M; Mishra, K; Mohanty, G B; Monge, M R; Monorchio, D; Moore, T B; Morandin, M; Morganti, M; Morganti, S; Morii, M; Muheim, F; Müller, D R; Nagel, M; Naisbit, M T; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nesom, G; Nicholson, H; Nikolich, M B; Nogowski, R; Nugent, I M; O'Grady, C P; Ocariz, J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Oyanguren, A; Ozcan, V E; Paar, H P; Pacetti, S; Palano, A; Palombo, F; Pan, B; Pan, Y; Panduro, W; Paoloni, E; Paolucci, P; Pappagallo, M; Park, W; Passaggio, S; Patel, P M; Patrignani, C; Patteri, P; Payne, D J; Pelizaeus, M; Perazzo, A; Perl, M; Peruzzi, I M; Peters, K; Petersen, B A; Petrella, A; Petzold, A; Piatenko, T; Piccolo, D; Piccolo, M; Piemontese, L; Pierini, M; Piredda, G; Playfer, S; Poireau, V; Polci, F; Pompili, A; Porter, F C; Posocco, M; Potter, C T; Prell, S; Prencipe, E; Prepost, R; Pripstein, M; Pruvot, S; Pulliam, T; Purohit, M V; Qi, N D; Rahatlou, S; Rahimi, A M; Rahmat, R; Rama, M; Ratcliff, B N; Raven, G; Regensburger, J J; Ricciardi, S; Richman, J D; Ritchie, J L; Rizzo, G; Roberts, D A; Robertson, A I; Robertson, S H; Robutti, E; Rodier, S; Roe, N A; Ronan, M T; Roney, J M; Rong, G; Roodman, A; Roos, L; Rosenberg, E I; Rotondo, M; Roudeau, P; Rubin, A E; Ruddick, W O; Röthel, W; Sacco, R; Saeed, M A; Safai-Tehrani, F; Saleem, M; Salnikov, A A; Salvatore, F; Sanders, D A; Santroni, A; Saremi, S; Satpathy, A; Schalk, T; Schenk, S; Schilling, C J; Schindler, R H; Schofield, K C; Schott, G; Schröder, T; Schröder, H; Schubert, J; Schubert, K R; Schumm, B A; Schune, M H; Schwiening, J; Schwierz, R; Schwitters, R F; Sciacca, C; Sciolla, G; Seiden, A; Sekula, S J; Serednyakov, S I; Serrano, J; Sharma, V; Shen, B C; Sherwood, D J; Simard, M; Simi, G; Simonetto, F; Sinev, N B; Skovpen, Yu I; Smith, A J S; Smith, J G; Snoek, H L; Snyder, A; Sobie, R J; Soffer, A; Sokoloff, M D; Solodov, E P; Spaan, B; Spanier, S M; Spitznagel, M; Spradlin, P; Steinke, M; Stelzer, J; Stocchi, A; Stoker, D P; Stroili, R; Strom, D; Strube, J; Stugu, B; Stängle, H; Su, D; Sullivan, M K; Summers, D J; Sundermann, J E; Suzuki, K; Swain, S K; Taras, P; Taylor, F; Telnov, A V; Teodorescu, L; Ter-Antonian, R; Therin, G; Thiebaux, C; Thompson, J M; Tisserand, V; Todyshev, Y K; Toki, W H; Torrence, E; Tosi, S; Touramanis, C; Ulmer, K A; Uwer, U; Van Bakel, N; Vasseur, G; Vavra, J; Vazquez, A; Verderi, M; Viaud, F B; Vitale, L; Voci, C; Voena, C; Volk, A; Wagner, A P; Wagner, S R; Wagoner, D E; Waldi, R; Walker, D; Walsh, J J; Wang, K; Wang, P; Wang, W F; Wappler, F R; Watson, A T; Weaver, M; Weinstein, A J R; Wenzel, W A; Wilden, L; Williams, D C; Williams, J C; Wilson, F F; Wilson, J R; Wilson, M G; Wilson, R J; Winklmeier, F; Wisniewski, W J; Wittgen, M; Wong, Q K; Wormser, G; Wren, A C; Wright, D H; Wright, D M; Wu, J; Wu, S L; Wulsin, H W; Xie, Y; Yamamoto, R K; Yarritu, A K; Ye, S; Yi, J I; Yi, K; Young, C C; Yu, Z; Yéche, C; Zain, S B; Zallo, A; Zeng, Q; Zghiche, A; Zhang, J; Zhang, L; Zhao, H W; Zhu, Y S; Ziegler, V; Zito, M; Çuhadar-Dönszelmann, T; al, et
2007-01-01
We perform an amplitude analysis of the decays B0->phi K^*_2(1430)0, phi K^*(892)0, and phi(K pi)^0_S-wave with a sample of about 384 million BBbar pairs recorded with the BABAR detector. The fractions of longitudinal polarization f_L of the vector-tensor and vector-vector decay modes are measured to be 0.853 +0.061-0.069 +-0.036 and 0.506 +-0.040 +-0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP-violation.
Execution of vector operations for Intel 860
Energy Technology Data Exchange (ETDEWEB)
Khaletskii, D.A.
1995-03-01
When designing a portable setup compiler from the C[] language, the compiler setup problem is solved for various SIMD computers. A vector and vector operations are defined in C[]. A map of vector operations is trivial for computers with vector registers. Some problems appear when mapping them to computers without vector registers. It is shown how to effectively perform vector operations for the 1860 microcomputer as an example of one without vector registers.
Vectors on the Basketball Court
Bergman, Daniel
2010-01-01
An Idea Bank published in the April/May 2009 issue of "The Science Teacher" describes an experiential physics lesson on vectors and vector addition (Brown 2009). Like its football predecessor, the basketball-based investigation presented in this Idea Bank addresses National Science Education Standards Content B, Physical Science, 9-12 (NRC 1996)…
Simplified Representation of Vector Fields
Telea, Alexandru; Wijk, Jarke J. van
1999-01-01
Vector field visualization remains a difficult task. Although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. We
The Neural Support Vector Machine
Wiering, Marco; van der Ree, Michiel; Embrechts, Mark; Stollenga, Marijn; Meijster, Arnold; Nolte, A; Schomaker, Lambertus
2013-01-01
This paper describes a new machine learning algorithm for regression and dimensionality reduction tasks. The Neural Support Vector Machine (NSVM) is a hybrid learning algorithm consisting of neural networks and support vector machines (SVMs). The output of the NSVM is given by SVMs that take a
Testing identifiablility of cointegrating vectors
H.P. Boswijk
1996-01-01
This article analyzes the identification and normalization of cointegrating vectors. Normalizing a cointegrating relation with respect to one of the relevant variables is with loss of generality; and restrictions that are supposed to identify a vector may fail to do so for particular parameter value
The Neural Support Vector Machine
Wiering, Marco; van der Ree, Michiel; Embrechts, Mark; Stollenga, Marijn; Meijster, Arnold; Nolte, A; Schomaker, Lambertus
2013-01-01
This paper describes a new machine learning algorithm for regression and dimensionality reduction tasks. The Neural Support Vector Machine (NSVM) is a hybrid learning algorithm consisting of neural networks and support vector machines (SVMs). The output of the NSVM is given by SVMs that take a centr
Estimation of Motion Vector Fields
DEFF Research Database (Denmark)
Larsen, Rasmus
1993-01-01
This paper presents an approach to the estimation of 2-D motion vector fields from time varying image sequences. We use a piecewise smooth model based on coupled vector/binary Markov random fields. We find the maximum a posteriori solution by simulated annealing. The algorithm generate sample...
Simplified Representation of Vector Fields
Telea, Alexandru; Wijk, Jarke J. van
1999-01-01
Vector field visualization remains a difficult task. Although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. We
GPU Accelerated Vector Median Filter
Aras, Rifat; Shen, Yuzhong
2011-01-01
Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .
Resolving Azimuth Ambiguity Using Vertical Nature of Solar Quiet-Sun Magnetic Fields
Gosain, Sanjay
2012-01-01
The measurement of solar magnetic fields using the Zeeman effect diagnostics has a fundamental 180 degree ambiguity in the determination of the azimuth angle of the transverse field component. There are several methods that are used in the community and each one has its merits and demerits. Here we present a disambiguation idea that is based on the assumption that most of the magnetic field on the sun is predominantly vertical. While the method is not applicable to penumbra or other features harboring predominantly horizontal fields like the sheared neutral lines, it is useful for regions where fields are predominantly vertical like network and plage areas. The method is tested with the full-disk solar vector magnetograms observed by the VSM/SOLIS instrument. We find that statistically about 60-85 % of the pixels in a typical full-disk magnetogram has field inclination in the range of 0-30 degrees with respect to the local solar normal, and thus can be successfully disambiguated by the proposed method. Due to...
DEFF Research Database (Denmark)
Holbek, Simon
For the last decade, the field of ultrasonic vector flow imaging has gotten an increasingly attention, as the technique offers a variety of new applications for screening and diagnostics of cardiovascular pathologies. The main purpose of this PhD project was therefore to advance the field of 3-D...... ultrasonic vector flow estimation and bring it a step closer to a clinical application. A method for high frame rate 3-D vector flow estimation in a plane using the transverse oscillation method combined with a 1024 channel 2-D matrix array is presented. The proposed method is validated both through phantom......, if this significant reduction in the element count can still provide precise and robust 3-D vector flow estimates in a plane. The study concludes that the RC array is capable of estimating precise 3-D vector flow both in a plane and in a volume, despite the low channel count. However, some inherent new challenges...
Emerging vector borne diseases – incidence through vectors
Directory of Open Access Journals (Sweden)
Sara eSavic
2014-12-01
Full Text Available Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases.During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples
Chikungunya Virus–Vector Interactions
Directory of Open Access Journals (Sweden)
Lark L. Coffey
2014-11-01
Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.
Stable piecewise polynomial vector fields
Directory of Open Access Journals (Sweden)
Claudio Pessoa
2012-09-01
Full Text Available Let $N={y>0}$ and $S={y<0}$ be the semi-planes of $mathbb{R}^2$ having as common boundary the line $D={y=0}$. Let $X$ and $Y$ be polynomial vector fields defined in $N$ and $S$, respectively, leading to a discontinuous piecewise polynomial vector field $Z=(X,Y$. This work pursues the stability and the transition analysis of solutions of $Z$ between $N$ and $S$, started by Filippov (1988 and Kozlova (1984 and reformulated by Sotomayor-Teixeira (1995 in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields $Z_{epsilon}$, defined by averaging $X$ and $Y$. This family approaches $Z$ when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002 providing conditions on $(X,Y$ for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on $mathbb{R}^2$. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.
Chikungunya Virus–Vector Interactions
Coffey, Lark L.; Failloux, Anna-Bella; Weaver, Scott C.
2014-01-01
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed. PMID:25421891
Vector control of induction machines
Robyns, Benoit
2012-01-01
After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for
Vector fields on nonorientable surfaces
Directory of Open Access Journals (Sweden)
Dorin Ghisa
2003-01-01
Full Text Available A one-to-one correspondence is established between the germs of functions and tangent vectors on a NOS X and the bi-germs of functions, respectively, elementary fields of tangent vectors (EFTV on the orientable double cover of X. Some representation theorems for the algebra of germs of functions, the tangent space at an arbitrary point of X, and the space of vector fields on X are proved by using a symmetrisation process. An example related to the normal derivative on the border of the MÃƒÂ¶bius strip supports the nontriviality of the concepts introduced in this paper.
DEFF Research Database (Denmark)
Davis, Christopher James; Kedlaya, Kiran
2014-01-01
We study the kernel and cokernel of the Frobenius map on the p-typical Witt vectors of a commutative ring, not necessarily of characteristic p. We give many equivalent conditions to surjectivity of the Frobenius map on both finite and infinite length Witt vectors. In particular, surjectivity...... on finite Witt vectors turns out to be stable under certain integral extensions; this provides a clean formulation of a strong generalization of Faltings’s almost purity theorem from p-adic Hodge theory, incorporating recent improvements by Kedlaya–Liu and by Scholze....
Vector boson scattering at CLIC
Energy Technology Data Exchange (ETDEWEB)
Kilian, Wolfgang; Fleper, Christian [Department Physik, Universitaet Siegen, 57068 Siegen (Germany); Reuter, Juergen [DESY Theory Group, 22603 Hamburg (Germany); Sekulla, Marco [Institut fuer Theoretische Physik, Karlsruher Institut fuer Technologie, 76131 Karlsruhe (Germany)
2016-07-01
Linear colliders operating in a range of multiple TeV are able to investigate the details of vector boson scattering and electroweak symmetry breaking. We calculate cross sections with the Monte Carlo generator WHIZARD for vector boson scattering processes at the future linear e{sup +} e{sup -} collider CLIC. By finding suitable cuts, the vector boson scattering signal processes are isolated from the background. Finally, we are able to determine exclusion sensitivities on the non-Standard Model parameters of the relevant dimension eight operators.
Synthetic Aperture Vector Flow Imaging
DEFF Research Database (Denmark)
Oddershede, Niels
2008-01-01
of the thesis considers a method for estimating the two-dimensional velocity vector within the image plane. This method, called synthetic aperture vector flow imaging, is first shortly reviewed. The main contribution of this work is partly an analysis of the method with respect to focusing effects, motion...... estimation. The method can be used for increasing the frame rate of color flow maps or alternatively for a new imaging modality entitled quadroplex imaging, featuring a color flow map and two independent spectrograms at a high frame rate. The second is an alternative method for ultrasonic vector velocity...
DEFF Research Database (Denmark)
Davis, Christopher James; Kedlaya, Kiran
2014-01-01
We study the kernel and cokernel of the Frobenius map on the p-typical Witt vectors of a commutative ring, not necessarily of characteristic p. We give many equivalent conditions to surjectivity of the Frobenius map on both finite and infinite length Witt vectors. In particular, surjectivity...... on finite Witt vectors turns out to be stable under certain integral extensions; this provides a clean formulation of a strong generalization of Faltings’s almost purity theorem from p-adic Hodge theory, incorporating recent improvements by Kedlaya–Liu and by Scholze....
Transcriptional Silencing of Retroviral Vectors
DEFF Research Database (Denmark)
Lund, Anders Henrik; Duch, M.; Pedersen, F.S.
1996-01-01
. Extinction of long-term vector expression has been observed after implantation of transduced hematopoietic cells as well as fibroblasts, myoblasts and hepatocytes. Here we review the influence of vector structure, integration site and cell type on transcriptional silencing. While down-regulation of proviral...... transcription is known from a number of cellular and animal models, major insight has been gained from studies in the germ line and embryonal cells of the mouse. Key elements for the transfer and expression of retroviral vectors, such as the viral transcriptional enhancer and the binding site for the t......RNA primer for reverse transcription may have a major influence on transcriptional silencing. Alterations of these elements of the vector backbone as well as the use of internal promoter elements from housekeeping genes may contribute to reduce transcriptional silencing. The use of cell culture and animal...
Acoustic vector sensor signal processing
Institute of Scientific and Technical Information of China (English)
SUN Guiqing; LI Qihu; ZHANG Bin
2006-01-01
Acoustic vector sensor simultaneously, colocately and directly measures orthogonal components of particle velocity as well as pressure at single point in acoustic field so that is possible to improve performance of traditional underwater acoustic measurement devices or detection systems and extends new ideas for solving practical underwater acoustic engineering problems. Although acoustic vector sensor history of appearing in underwater acoustic area is no long, but with huge and potential military demands, acoustic vector sensor has strong development trend in last decade, it is evolving into a one of important underwater acoustic technology. Under this background, we try to review recent progress in study on acoustic vector sensor signal processing, such as signal detection, DOA estimation, beamforming, and so on.
Introduction to matrices and vectors
Schwartz, Jacob T
2001-01-01
In this concise undergraduate text, the first three chapters present the basics of matrices - in later chapters the author shows how to use vectors and matrices to solve systems of linear equations. 1961 edition.
GRE Enzymes for Vector Analysis
U.S. Environmental Protection Agency — Microbial enzyme data that were collected during the 2004-2006 EMAP-GRE program. These data were then used by Moorhead et al (2016) in their ecoenzyme vector...
All optical vector magnetometer Project
National Aeronautics and Space Administration — This Phase I research project will investigate a novel method of operating an atomic magnetometer to simultaneously measure total magnetic fields and vector magnetic...
Unsupervised learning of binary vectors
Copelli Lopes da Silva, Mauro
In this thesis, unsupervised learning of binary vectors from data is studied using methods from Statistical Mechanics of disordered systems. In the model, data vectors are distributed according to a single symmetry-breaking direction. The aim of unsupervised learning is to provide a good approximation to this direction. The difference with respect to previous studies is the knowledge that this preferential direction has binary components. It is shown that sampling from the posterior distribution (Gibbs learning) leads, for general smooth distributions, to an exponentially fast approach to perfect learning in the asymptotic limit of large number of examples. If the distribution is non-smooth, then first order phase transitions to perfect learning are expected. In the limit of poor performance, a second order phase transition ("retarded learning") is predicted to occur if the data distribution is not biased. Using concepts from Bayesian inference, the center of mass of the Gibbs ensemble is shown to have maximal average (Bayes-optimal) performance. This upper bound for continuous vectors is extended to a discrete space, resulting in the clipped center of mass of the Gibbs ensemble having maximal average performance among the binary vectors. To calculate the performance of this best binary vector, the geometric properties of the center of mass of binary vectors are studied. The surprising result is found that the center of mass of infinite binary vectors which obey some simple constraints, is again a binary vector. When disorder is taken into account in the calculation, however, a vector with continuous components is obtained. The performance of the best binary vector is calculated and shown to always lie above that of Gibbs learning and below the Bayes-optimal performance. Making use of a variational approach under the replica symmetric ansatz, an optimal potential is constructed in the limits of zero temperature and mutual overlap 1. Minimization of this potential
Giacosa, Francesco; Janowski, Stanislaus
2016-01-01
We calculate two- and three-body decays of the (lightest) vector glueball into (pseudo)scalar, (axial-)vector, as well as pseudovector and excited vector mesons. By setting the mass of this yet hypothetical vector glueball to 3.8 GeV as predicted by Lattice QCD, many branching ratios can be computed and represent a parameter-free prediction of our approach. We find that the decay mode $\\omega\\pi\\pi$ should be one of the largest (both through the decay chain $\\mathcal{O}\\rightarrow b_{1}\\pi\\rightarrow$ $\\omega\\pi\\pi$ and through the direct coupling $\\mathcal{O}\\rightarrow\\omega\\pi\\pi$)$.$ Similarly, the (direct and indirect) decay into $\\pi KK^{\\ast}(892)$ is sizable. Moreover, the decays into $\\rho\\pi$ and $K^{\\ast}(892)K$ are, although subleading, possible and could play a role in explaining the $\\rho\\pi$ puzzle of the charmonium state $\\psi(2S)$ thank to a (small) mixing with the vector glueball. The vector glueball can be directly formed at the ongoing BESIII experiment as well as at the future PANDA exper...
Hagedorn, Claudia; Baiker, Armin; Postberg, Jan; Ehrhardt, Anja; Lipps, Hans J
2012-06-01
Nonviral episomal vectors represent attractive alternatives to currently used virus-based expression systems. In the late 1990s, it was shown that a plasmid containing an expression cassette linked to a scaffold/matrix attached region (S/MAR) replicates as a low copy number episome in all cell lines tested, as well as primary cells, and can be used for the genetic modification of higher animals. Once established in the cell, the S/MAR vector replicates early during S-phase and, in the absence of selection, is stably retained in the cells for an unlimited period of time. This vector can therefore be regarded as a minimal model system for studying the epigenetic regulation of replication and functional nuclear architecture. In theory, this construct represents an almost "ideal" expression system for gene therapy. In practice, S/MAR-based vectors stably modify mammalian cells with efficiencies far below those of virus-based constructs. Consequently, they have not yet found application in gene therapy trials. Furthermore, S/MAR vector systems are not trivial to handle and several critical technical issues have to be considered when modifying these vectors for various applications.
Are Bred Vectors The Same As Lyapunov Vectors?
Kalnay, E.; Corazza, M.; Cai, M.
Regional loss of predictability is an indication of the instability of the underlying flow, where small errors in the initial conditions (or imperfections in the model) grow to large amplitudes in finite times. The stability properties of evolving flows have been studied using Lyapunov vectors (e.g., Alligood et al, 1996, Ott, 1993, Kalnay, 2002), singular vectors (e.g., Lorenz, 1965, Farrell, 1988, Molteni and Palmer, 1993), and, more recently, with bred vectors (e.g., Szunyogh et al, 1997, Cai et al, 2001). Bred vectors (BVs) are, by construction, closely related to Lyapunov vectors (LVs). In fact, after an infinitely long breeding time, and with the use of infinitesimal ampli- tudes, bred vectors are identical to leading Lyapunov vectors. In practical applications, however, bred vectors are different from Lyapunov vectors in two important ways: a) bred vectors are never globally orthogonalized and are intrinsically local in space and time, and b) they are finite-amplitude, finite-time vectors. These two differences are very significant in a dynamical system whose size is very large. For example, the at- mosphere is large enough to have "room" for several synoptic scale instabilities (e.g., storms) to develop independently in different regions (say, North America and Aus- tralia), and it is complex enough to have several different possible types of instabilities (such as barotropic, baroclinic, convective, and even Brownian motion). Bred vectors share some of their properties with leading LVs (Corazza et al, 2001a, 2001b, Toth and Kalnay, 1993, 1997, Cai et al, 2001). For example, 1) Bred vectors are independent of the norm used to define the size of the perturba- tion. Corazza et al. (2001) showed that bred vectors obtained using a potential enstro- phy norm were indistinguishable from bred vectors obtained using a streamfunction squared norm, in contrast with singular vectors. 2) Bred vectors are independent of the length of the rescaling period as long as the
Containment of arthropod disease vectors.
Scott, Thomas W
2005-01-01
Effective containment of arthropod vectors of infectious diseases is necessary to prevent transmission of pathogens by released, infected vectors and to prevent vectors that escape from establishing populations that subsequently contribute to increased disease. Although rare, past releases illustrate what can go wrong and justify the need for guidelines that minimize risks. An overview of recommendations for insectary facilities, practices, and equipment is provided, and features of four recently published and increasingly rigorous arthropod containment levels (ACLs 1-4) are summarized. ACL-1 is appropriate for research that constitutes the lowest risk level, including uninfected arthropods or vectors that are infected with micro-organisms that do not cause disease in humans, domestic animals, or wildlife. ACL-2 is appropriate for indigenous and exotic arthropods that represent a moderate risk, including vectors infected or suspected of being infected with biosafety level (BSL)-2 infectious agents and arthropods that have been genetically modified in ways that do not significantly affect their fecundity, survival, host preference, or vector competence. ACL-3 is recommended for arthropods that are or may be infected with BSL-3 infectious agents. ACL-3 places greater emphasis on pathogen containment and more restricted access to the insectary than ACL-2. ACL-4 is intended for arthropods that are infected with the most dangerous BSL-4 infectious agents, which can cause life-threatening illness by aerosol or arthropod bite. Adherence to these guidelines will result in laboratory-based arthropod vector research that minimizes risks and results in important new contributions to applied and basic science.
Fan, Zhong-Ying
2016-09-01
In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.
Giacosa, Francesco; Sammet, Julia; Janowski, Stanislaus
2017-06-01
We calculate two- and three-body decays of the (lightest) vector glueball into (pseudo)scalar, (axial-)vector, as well as pseudovector and excited vector mesons in the framework of a model of QCD. While absolute values of widths cannot be predicted because the corresponding coupling constants are unknown, some interesting branching ratios can be evaluated by setting the mass of the yet hypothetical vector glueball to 3.8 GeV as predicted by quenched lattice QCD. We find that the decay mode ω π π should be one of the largest (both through the decay chain O →b1π →ω π π and through the direct coupling O →ω π π ). Similarly, the (direct and indirect) decay into π K K*(892 ) is sizable. Moreover, the decays into ρ π and K*(892 )K are, although subleading, possible and could play a role in explaining the ρ π puzzle of the charmonium state ψ (2 S ) thanks to a (small) mixing with the vector glueball. The vector glueball can be directly formed at the ongoing BESIII experiment as well as at the future PANDA experiment at the FAIR facility. If the width is sufficiently small (≲100 MeV ) it should not escape future detection. It should be stressed that the employed model is based on some inputs and simplifying assumptions: the value of glueball mass (at present, the quenched lattice value is used), the lack of mixing of the glueball with other quarkonium states, and the use of few interaction terms. It then represents a first step toward the identification of the main decay channels of the vector glueball, but shall be improved when corresponding experimental candidates and/or new lattice results will be available.
A NOTE ON VECTOR CASCADE ALGORITHM
Institute of Scientific and Technical Information of China (English)
Qiu-hui Chen; Jin-zhao Liu; Wen-sheng Zhang
2002-01-01
The focus of this paper is on the relationship between accuracy of multivariate refinable vector and vector cascade algorithm. We show that, if the vector cascade algorithm (1.5) with isotropic dilation converges to a vector-valued function with regularity, then the initial function must satisfy the Strang-Fix conditions.
Project Physics Programmed Instruction, Vectors 1.
Harvard Univ., Cambridge, MA. Harvard Project Physics.
This programmed instruction booklet is an interim version of instructional materials being developed by Harvard Project Physics. It is the first in a series of three booklets on vectors and covers the definitions of vectors and scalars, drawing vector quantities to scale, and negative vectors. For others in this series, see SE 015 550 and SE 015…
Project Physics Programmed Instruction, Vectors 2.
Harvard Univ., Cambridge, MA. Harvard Project Physics.
This is the second of a series of three programmed instruction booklets on vectors developed by Harvard Project Physics. It covers adding two or more vectors together, and finding a third vector that could be added to two given vectors to make a sum of zero. For other booklets in this series, see SE 015 549 and SE 015 551. (DT)
The Duality on Vector Optimization Problems
Institute of Scientific and Technical Information of China (English)
HUANG Long-guang
2012-01-01
Duality framework on vector optimization problems in a locally convex topological vector space are established by using scalarization with a cone-strongly increasing function.The dualities for the scalar convex composed optimization problems and for general vector optimization problems are studied.A general approach for studying duality in vector optimization problems is presented.
The biological control of disease vectors.
Okamoto, Kenichi W; Amarasekare, Priyanga
2012-09-21
Vector-borne diseases are common in nature and can have a large impact on humans, livestock and crops. Biological control of vectors using natural enemies or competitors can reduce vector density and hence disease transmission. However, the indirect interactions inherent in host-vector disease systems make it difficult to use traditional pest control theory to guide biological control of disease vectors. This necessitates a conceptual framework that explicitly considers a range of indirect interactions between the host-vector disease system and the vector's biological control agent. Here we conduct a comparative analysis of the efficacy of different types of biological control agents in controlling vector-borne diseases. We report three key findings. First, highly efficient predators and parasitoids of the vector prove to be effective biological control agents, but highly virulent pathogens of the vector also require a high transmission rate to be effective. Second, biocontrol agents can successfully reduce long-term host disease incidence even though they may fail to reduce long-term vector densities. Third, inundating a host-vector disease system with a natural enemy of the vector has little or no effect on reducing disease incidence, but inundating the system with a competitor of the vector has a large effect on reducing disease incidence. The comparative framework yields predictions that are useful in developing biological control strategies for vector-borne diseases. We discuss how these predictions can inform ongoing biological control efforts for host-vector disease systems.
Vector-valued automorphic forms and vector bundles
Saber, Hicham
2013-01-01
For an arbitrary discrete group $\\Gamma$ and an $n$-dimensional complex representation $R$ of $\\Gamma$, we prove the existence of $n$ linearly independent vector-valued automorphic forms for $\\Gamma$ with multiplier $R$. To this end, we realize these automorphic forms as sections of a rank $n$ vector bundle attached to a 1-cocycle with coefficients in the sheaf $\\mbox{GL}(n,{\\mathcal O}_X)$, $X$ being the quotient of the Poincar\\'e half-plane by $\\Gamma$ completed with the cusps of $\\Gamma$.
Implementing Bayesian Vector Autoregressions Implementing Bayesian Vector Autoregressions
Directory of Open Access Journals (Sweden)
Richard M. Todd
1988-03-01
Full Text Available Implementing Bayesian Vector Autoregressions This paper discusses how the Bayesian approach can be used to construct a type of multivariate forecasting model known as a Bayesian vector autoregression (BVAR. In doing so, we mainly explain Doan, Littermann, and Sims (1984 propositions on how to estimate a BVAR based on a certain family of prior probability distributions. indexed by a fairly small set of hyperparameters. There is also a discussion on how to specify a BVAR and set up a BVAR database. A 4-variable model is used to iliustrate the BVAR approach.
Vector Encoding in Biochemical Networks
Potter, Garrett; Sun, Bo
Encoding of environmental cues via biochemical signaling pathways is of vital importance in the transmission of information for cells in a network. The current literature assumes a single cell state is used to encode information, however, recent research suggests the optimal strategy utilizes a vector of cell states sampled at various time points. To elucidate the optimal sampling strategy for vector encoding, we take an information theoretic approach and determine the mutual information of the calcium signaling dynamics obtained from fibroblast cells perturbed with different concentrations of ATP. Specifically, we analyze the sampling strategies under the cases of fixed and non-fixed vector dimension as well as the efficiency of these strategies. Our results show that sampling with greater frequency is optimal in the case of non-fixed vector dimension but that, in general, a lower sampling frequency is best from both a fixed vector dimension and efficiency standpoint. Further, we find the use of a simple modified Ornstein-Uhlenbeck process as a model qualitatively captures many of our experimental results suggesting that sampling in biochemical networks is based on a few basic components.
Ensemble Dynamics and Bred Vectors
Balci, Nusret; Restrepo, Juan M; Sell, George R
2011-01-01
We introduce the new concept of an EBV to assess the sensitivity of model outputs to changes in initial conditions for weather forecasting. The new algorithm, which we call the "Ensemble Bred Vector" or EBV, is based on collective dynamics in essential ways. By construction, the EBV algorithm produces one or more dominant vectors. We investigate the performance of EBV, comparing it to the BV algorithm as well as the finite-time Lyapunov Vectors. We give a theoretical justification to the observed fact that the vectors produced by BV, EBV, and the finite-time Lyapunov vectors are similar for small amplitudes. Numerical comparisons of BV and EBV for the 3-equation Lorenz model and for a forced, dissipative partial differential equation of Cahn-Hilliard type that arises in modeling the thermohaline circulation, demonstrate that the EBV yields a size-ordered description of the perturbation field, and is more robust than the BV in the higher nonlinear regime. The EBV yields insight into the fractal structure of th...
Gauge Theories of Vector Particles
Glashow, S. L.; Gell-Mann, M.
1961-04-24
The possibility of generalizing the Yang-Mills trick is examined. Thus we seek theories of vector bosons invariant under continuous groups of coordinate-dependent linear transformations. All such theories may be expressed as superpositions of certain "simple" theories; we show that each "simple theory is associated with a simple Lie algebra. We may introduce mass terms for the vector bosons at the price of destroying the gauge-invariance for coordinate-dependent gauge functions. The theories corresponding to three particular simple Lie algebras - those which admit precisely two commuting quantum numbers - are examined in some detail as examples. One of them might play a role in the physics of the strong interactions if there is an underlying super-symmetry, transcending charge independence, that is badly broken. The intermediate vector boson theory of weak interactions is discussed also. The so-called "schizon" model cannot be made to conform to the requirements of partial gauge-invariance.
DEFF Research Database (Denmark)
Pihl, Michael Johannes
The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse...... on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5...
DEFF Research Database (Denmark)
Holbek, Simon
studies and in vivo. Phantom measurements are compared with their corresponding reference value, whereas the in vivo measurement is validated against the current golden standard for non-invasive blood velocity estimates, based on magnetic resonance imaging (MRI). The study concludes, that a high precision......, if this significant reduction in the element count can still provide precise and robust 3-D vector flow estimates in a plane. The study concludes that the RC array is capable of estimating precise 3-D vector flow both in a plane and in a volume, despite the low channel count. However, some inherent new challenges......For the last decade, the field of ultrasonic vector flow imaging has gotten an increasingly attention, as the technique offers a variety of new applications for screening and diagnostics of cardiovascular pathologies. The main purpose of this PhD project was therefore to advance the field of 3-D...
Skyrmions with vector mesons revisited
Oh, Yongseok
2014-01-01
In order to develop a model that can describe both a single baryon and multi-baryon systems on the same footing, we re-investigate the Skyrme model in a chiral Lagrangian derived from the hidden local symmetry (HLS) up to $O(p^4)$ including the homogeneous Wess-Zumino terms. We use the master formulas that connect the parameters of the HLS Lagrangian and a class of holographic QCD models, which provides a controllable way to determine the low-energy constants of the Lagrangian once the pion decay constant and the vector meson mass are given. Therefore, this model allows us to study the role of vector mesons in the skyrmion structure. We find that the $\\rho$ and $\\omega$ vector mesons have different roles in the skyrmion structure and that the $\\omega$ meson has an important role in the properties of the nucleon.
Quantum contextuality for rational vectors
Cabello, Adan
2010-01-01
The Kochen-Specker theorem states that noncontextual hidden variable models are inconsistent with the quantum predictions for every yes-no question on a qutrit, corresponding to every projector in three dimensions. It has been suggested [D. A. Meyer, Phys. Rev. Lett. 83, 3751 (1999)] that the inconsistency would disappear when we are restricted to projectors on unit vectors with rational components; that noncontextual hidden variables could reproduce the quantum predictions for rational vectors. Here we show that a qutrit state with rational components violates an inequality valid for noncontextual hidden-variable models [A. A. Klyachko et al., Phys. Rev. Lett. 101, 020403 (2008)] using rational projectors. This shows that the inconsistency remains even when using only rational vectors.
Vector bundles on toric varieties
Gharib, Saman
2011-01-01
Following Sam Payne's work, we study the existence problem of nontrivial vector bundles on toric varieties. The first result we prove is that every complete fan admits a nontrivial conewise linear multivalued function. Such functions could potentially be the Chern classes of toric vector bundles. Then we use the results of Corti\\~nas, Haesemeyer, Walker and Weibel to show that the (non-equivariant) Grothendieck group of the toric 3-fold studied by Payne is large, so the variety has a nontrivial vector bundle. Using the same computation, we show that every toric 3-fold X either has a nontrivial line bundle, or there is a finite surjective toric morphism from Y to X, such that Y has a large Grothendieck group.
Quantum contextuality for rational vectors
Energy Technology Data Exchange (ETDEWEB)
Cabello, Adan, E-mail: adan@us.e [Departamento de Fisica Aplicada II, Universidad de Sevilla, E-41012 Sevilla (Spain); Larsson, Jan-Ake, E-mail: jan-ake.larsson@liu.s [Institutionen foer Systemteknik, Linkoepings Universitet, SE-581 83 Linkoeping (Sweden)
2010-12-01
The Kochen-Specker theorem states that noncontextual hidden variable models are inconsistent with the quantum predictions for every yes-no question on a qutrit, corresponding to every projector in three dimensions. It has been suggested [D.A. Meyer, Phys. Rev. Lett. 83 (1999) 3751] that the inconsistency would disappear when restricting to projectors on unit vectors with rational components; that noncontextual hidden variables could reproduce the quantum predictions for rational vectors. Here we show that a qutrit state with rational components violates an inequality valid for noncontextual hidden-variable models [A.A. Klyachko et al., Phys. Rev. Lett. 101 (2008) 020403] using rational projectors. This shows that the inconsistency remains even when using only rational vectors.
Learning with Support Vector Machines
Campbell, Colin
2010-01-01
Support Vectors Machines have become a well established tool within machine learning. They work well in practice and have now been used across a wide range of applications from recognizing hand-written digits, to face identification, text categorisation, bioinformatics, and database marketing. In this book we give an introductory overview of this subject. We start with a simple Support Vector Machine for performing binary classification before considering multi-class classification and learning in the presence of noise. We show that this framework can be extended to many other scenarios such a
Requirements for airborne vector gravimetry
Schwarz, K. P.; Colombo, O.; Hein, G.; Knickmeyer, E. T.
1992-01-01
The objective of airborne vector gravimetry is the determination of the full gravity disturbance vector along the aircraft trajectory. The paper briefly outlines the concept of this method using a combination of inertial and GPS-satellite data. The accuracy requirements for users in geodesy and solid earth geophysics, oceanography and exploration geophysics are then specified. Using these requirements, accuracy specifications for the GPS subsystem and the INS subsystem are developed. The integration of the subsystems and the problems connected with it are briefly discussed and operational methods are indicated that might reduce some of the stringent accuracy requirements.
Vector Theory in Relativistic Thermodynamics
Institute of Scientific and Technical Information of China (English)
刘泽文
1994-01-01
It is pointed out that five defects occur in Planck-Einstein’s relativistic thermodynamics (P-E theory). A vector theory in relativistic thermodynamics (VTRT) is established. Defining the internal energy as a 4-vector, and supposing the entropy and the number of. particles to be invariants we have derived the transformations of all quantities, and subsequently got the Lagrangian and 4-D forms of thermodynamic laws. In order to test the new theory, several exact solutions with classical limits are given. The VTRT is free from the defects of the P-E theory.
Vector-meson dominance revisited
Directory of Open Access Journals (Sweden)
Terschlüsen Carla
2012-12-01
Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.
Parallel Sparse Matrix - Vector Product
DEFF Research Database (Denmark)
Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd
This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...
The consequences of poor vectorization
CERN. Geneva
2016-01-01
This talk briefly discusses the vectorization problem and how it impacts scientific and engineering systems. A simple cost model of designing such system in context of different phases of software lifetime is considered. Finally a concept for scalable solution is presented.
Sparse Matrix Vector Processing Formats
Stathis, P.T.
2004-01-01
In this dissertation we have identified vector processing shortcomings related to the efficient storing and processing of sparse matrices. To alleviate existent problems we propose two storage formats denoted as Block Based Compression Storage (BBCS) format and Hierarchical Sparse Matrix (HiSM) stor
Bifurcations of optimal vector fields
Kiseleva, T.; Wagener, F.
2015-01-01
We study the structure of the solution set of a class of infinite-horizon dynamic programming problems with one-dimensional state spaces, as well as their bifurcations, as problem parameters are varied. The solutions are represented as the integral curves of a multivalued optimal vector field on sta
Portfolio Analysis for Vector Calculus
Kaplan, Samuel R.
2015-01-01
Classic stock portfolio analysis provides an applied context for Lagrange multipliers that undergraduate students appreciate. Although modern methods of portfolio analysis are beyond the scope of vector calculus, classic methods reinforce the utility of this material. This paper discusses how to introduce classic stock portfolio analysis in a…
Phlebotomine Vectors of Human Disease.
1983-12-30
different. We refrain from naming this specimen until more material becomes available. 12. Lutzomyia olmeca bicolor Fairchild and Theodor 1971...Castillo (1958) and Arzube (1960). Lutzomyia olmeca bicolor is the suspected vector of Leishmania mexicana aristedesi among rodents and marsupials in
Phase transitions in Vector Quantization
Witoelar, Aree; Ghosh, Anarta; Biehl, Michael; Verleysen, Michel
2008-01-01
We study Winner-Takes-All and rank based Vector Quantization along the lines of the statistical physics of off-line learning. Typical behavior of the system is obtained within a model where high-dimensional training data are drawn from a mixture of Gaussians. The analysis becomes exact in the simpli
Portfolio Analysis for Vector Calculus
Kaplan, Samuel R.
2015-01-01
Classic stock portfolio analysis provides an applied context for Lagrange multipliers that undergraduate students appreciate. Although modern methods of portfolio analysis are beyond the scope of vector calculus, classic methods reinforce the utility of this material. This paper discusses how to introduce classic stock portfolio analysis in a…
SCALAR AND VECTOR IN COMPULATION
Directory of Open Access Journals (Sweden)
Valery F. Ochkov
2013-01-01
Full Text Available The article deals with two fundamental data types – scalar and vector (array, without the ability of working with them one cannot solve using computer school or university tasks in mathematics, physics, chemistry and other technical training courses. Some fundamentals of teaching computer science at school and university are covered as well.
Vector-valued fuzzy multifunctions
Directory of Open Access Journals (Sweden)
Ismat Beg
2001-01-01
Full Text Available Some of the properties of vector-valued fuzzy multifunctions are studied. The notion of sum fuzzy multifunction, convex hull fuzzy multifunction, close convex hull fuzzy multifunction, and upper demicontinuous are given, and some of the properties of these fuzzy multifunctions are investigated.
Scalar Calibration of Vector Magnetometers
DEFF Research Database (Denmark)
Merayo, José M.G.; Brauer, Peter; Primdahl, Fritz;
2000-01-01
The calibration parameters of a vector magnetometer are estimated only by the use of a scalar reference magnetometer. The method presented in this paper differs from those previously reported in its linearized parametrization. This allows the determination of three offsets or signals in the absence...
Biosafety features of lentiviral vectors.
Schambach, Axel; Zychlinski, Daniela; Ehrnstroem, Birgitta; Baum, Christopher
2013-02-01
Over the past decades, lentiviral vectors have evolved as a benchmark tool for stable gene transfer into cells with a high replicative potential. Their relatively flexible genome and ability to transduce many forms of nondividing cells, combined with the potential for cell-specific pseudotyping, provides a rich resource for numerous applications in experimental platforms and therapeutic settings. Here, we give an overview of important biosafety features of lentiviral vectors, with detailed discussion of (i) the principles of the lentiviral split-genome design used for the construction of packaging cells; (ii) the relevance of modifications introduced into the lentiviral long terminal repeat (deletion of enhancer/promoter sequences and introduction of insulators); (iii) the basic features of mRNA processing, including the Rev/Rev-responsive element (RRE) interaction and the modifications of the 3' untranslated region of lentiviral vectors with various post-transcriptional regulatory elements affecting transcriptional termination, polyadenylation, and differentiation-specific degradation of mRNA; and (iv) the characteristic integration pattern with the associated risk of transcriptional interference with cellular genes. We conclude with considerations regarding the importance of cell targeting via envelope modifications. Along this course, we address canonical biosafety issues encountered with any type of viral vector: the risks of shedding, mobilization, germline transmission, immunogenicity, and insertional mutagenesis.
Vector ecology of equine piroplasmosis
Equine piroplasmosis (EP) is a disease of equidae including horses, donkeys, mules and zebras caused by either of two protozoan parasites, Theileria equi or Babesia caballi. These parasites are biologically transmitted between hosts via tick-vectors and although they have inherent differences, they ...
Parallel Sparse Matrix - Vector Product
DEFF Research Database (Denmark)
Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd
This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...
Vector Bundles over Elliptic Fibrations
Friedman, R; Witten, Edward; Friedman, Robert; Morgan, John W.; Witten, Edward
1997-01-01
This paper gives various methods for constructing vector bundles over elliptic curves and more generally over families of elliptic curves. We construct universal families over generalized elliptic curves via spectral cover methods and also by extensions, and then give a relative version of the construction in families. We give various examples and make Chern class computations.
Large N Expansion. Vector Models
Nissimov, E; Nissimov, Emil; Pacheva, Svetlana
2006-01-01
Preliminary version of a contribution to the "Quantum Field Theory. Non-Perturbative QFT" topical area of "Modern Encyclopedia of Mathematical Physics" (SELECTA), eds. Aref'eva I, and Sternheimer D, Springer (2007). Consists of two parts - "main article" (Large N Expansion. Vector Models) and a "brief article" (BPHZL Renormalization).
Vector variational inequalities and their relations with vector optimization
Directory of Open Access Journals (Sweden)
Surjeet Kaur Suneja
2014-01-01
Full Text Available In this paper, K- quasiconvex, K- pseudoconvex and other related functions have been introduced in terms of their Clarke subdifferentials, where is an arbitrary closed convex, pointed cone with nonempty interior. The (strict, weakly -pseudomonotonicity, (strict K- naturally quasimonotonicity and K- quasimonotonicity of Clarke subdifferential maps have also been defined. Further, we introduce Minty weak (MVVIP and Stampacchia weak (SVVIP vector variational inequalities over arbitrary cones. Under regularity assumption, we have proved that a weak minimum solution of vector optimization problem (VOP is a solution of (SVVIP and under the condition of K- pseudoconvexity we have obtained the converse for MVVIP (SVVIP. In the end we study the interrelations between these with the help of strict K-naturally quasimonotonicity of Clarke subdifferential map.
Vector-Boson Fusion and Vector-Boson Scattering
Rauch, Michael
2016-01-01
Vector-boson fusion and vector-boson scattering are an important class of processes for the Large Hadron Collider at CERN. It is characterized by two high-energetic jets in the forward regions of the detector and reduced jet activity in the central region. The higher center-of-mass energy during the current and subsequent runs strongly boosts the sensitivity in these processes and allows to test the predictions of the Standard Model to a high precision. In this review, we first present the main phenomenological features of vector-boson fusion and scattering processes. Then we discuss the effects of higher-order corrections, which are available at NLO QCD for all processes and up to N3LO QCD and NLO electro-weak for VBF-H production. An additional refinement is the addition of parton-shower effects, where recently a lot of progress has been made. The appearance of triple and quartic gauge vertices in the production processes enables us to probe anomalous gauge couplings. We introduce and compare the different ...
Symbolic Vector Analysis in Plasma Physics
Energy Technology Data Exchange (ETDEWEB)
Qin, H.; Tang, W.M.; Rewoldt, G.
1997-10-09
Many problems in plasma physics involve substantial amounts of analytical vector calculation. The complexity usually originates from both the vector operations themselves and the choice of underlying coordinate system. A computer algebra package for symbolic vector analysis in general coordinate systems, General Vector Analysis (GVA), is developed using Mathematica. The modern viewpoint for 3D vector calculus, differential forms on 3-manifolds, is adopted to unify and systematize the vector calculus operations in general coordinate systems. This package will benefit physicists and applied mathematicians in their research where complicated vector analysis is required. It will not only save a huge amount of human brain-power and dramatically improve accuracy, but this package will also be an intelligent tool to assist researchers in finding the right approaches to their problems. Several applications of this symbolic vector analysis package to plasma physics are also given.
Symbolic Vector Analysis in Plasma Physics
Energy Technology Data Exchange (ETDEWEB)
Qin, H.; Rewoldt, G.; Tang, W.M.
1997-10-01
Many problems in plasma physics involve substantial amounts of analytical vector calculation. The complexity usually originates from both the vector operations themselves and the choice of underlying coordinate system. A computer algebra package for symbolic vector analysis in general coordinate systems, GeneralVectorAnalysis (GVA), is developed using Mathematica. The modern viewpoint for 3D vector calculus, differential forms on 3-manifolds, is adopted to unify and systematize the vector calculus operations in general coordinate systems. This package will benefit physicists and applied mathematicians in their research where complicated vector analysis is required. It will not only save a huge amount of human brain-power and dramatically improve accuracy, but this package will also be an intelligent tool to assist researchers in finding the right approaches to their problems. Several applications of this symbolic vector analysis package to plasma physics are also given.
On third order integrable vector Hamiltonian equations
Meshkov, A. G.; Sokolov, V. V.
2017-03-01
A complete list of third order vector Hamiltonian equations with the Hamiltonian operator Dx having an infinite series of higher conservation laws is presented. A new vector integrable equation on the sphere is found.
SYSTEM OF GENERALIZED VECTOR VARIATIONAL INEQUALITIES
Institute of Scientific and Technical Information of China (English)
Fang Yaping; Huang Nanjing
2005-01-01
In this paper, the authors introduce and study system of generalized vector variational inequalities. Under suitable conditions, the existence of solutions for system of generalized vector variational inequalities is presented by Kakutani-Fan-Glicksberg fixed point theorem.
NEVILLE-TYPE VECTOR VALUED RATIONAL INTERPOLANTS
Institute of Scientific and Technical Information of China (English)
陈之兵; 顾传青; 徐晨
2004-01-01
A new kind of vector valued rational interpolants is established by means of Samelson inverse, with scalar numerator and vector valued denominator. It is essen tially different from that of Graves-Morris(1983), where the interpolants are constructed by Thiele-type continued fractions with vector valued numerator and scalar denominator. The new approach is more suitable to calculate the value of a vector valued function for a given point. And an error formula is also given and proven.
Vectors and translations in mathematics and physics
Dorier, Jean-Luc
2016-01-01
In mathematics, students learn about vectors and translation, in physics they model forces, speed, acceleration, etc. with vectors and study movements of translation. Do they make the connection between these concepts introduced in different disciplines or do they put things in separate boxes? In this paper we will start with some partial considerations on the history of vectors and we will give some references. Then we will show some examples of naïve illustrations of vectors from physics in...
Diffractive Leptoproduction of Vector Mesons in QCD
Brodsky, Stanley J.; Frankfurt, L.; Gunion, J. F.; Mueller, A.H.; Strikman, M.
1994-01-01
We demonstrate that the distinctive features of the forward differential cross section of diffractive leptoproduction of a vector meson can be legitimately calculated in perturbative QCD in terms of the light-cone $q \\bar q$ wave function of the vector meson and the gluon distribution of the target. In particular, we calculate the $Q^2$ and nuclear dependence of the diffractive leptoproduction of vector mesons and estimate the cross section. The production of longitudinally polarized vector m...
Medium Modification of Vector Mesons
Energy Technology Data Exchange (ETDEWEB)
Chaden Djalali, Michael Paolone, Dennis Weygand, Michael H. Wood, Rakhsha Nasseripour
2011-03-01
The theory of the strong interaction, Quantum Chromodynamics (QCD), has been remarkably successful in describing high-energy and short-distance-scale experiments involving quarks and gluons. However, applying QCD to low energy and large-distance scale experiments has been a major challenge. Various QCD-inspired models predict a partial restoration of chiral symmetry in nuclear matter with modifications of the properties of hadrons from their free-space values. Measurable changes such as a shift in mass and/or a change of width are predicted at normal nuclear density. Photoproduction of vector mesons off nuclei have been performed at different laboratories. The properties of the ρ, ω and φ mesons are investigated either directly by measuring their mass spectra or indirectly through transparency ratios. The latest results regarding medium modifications of the vector mesons in the nuclear medium will be discussed.
Lentiviral vectors in cancer immunotherapy.
Oldham, Robyn Aa; Berinstein, Elliot M; Medin, Jeffrey A
2015-01-01
Basic science advances in cancer immunotherapy have resulted in various treatments that have recently shown success in the clinic. Many of these therapies require the insertion of genes into cells to directly kill them or to redirect the host's cells to induce potent immune responses. Other analogous therapies work by modifying effector cells for improved targeting and enhanced killing of tumor cells. Initial studies done using γ-retroviruses were promising, but safety concerns centered on the potential for insertional mutagenesis have highlighted the desire to develop other options for gene delivery. Lentiviral vectors (LVs) have been identified as potentially more effective and safer alternative delivery vehicles. LVs are now in use in clinical trials for many different types of inherited and acquired disorders, including cancer. This review will discuss current knowledge of LVs and the applications of this viral vector-based delivery vehicle to cancer immunotherapy.
Clinical applications of power vectors.
Miller, Joseph M
2009-06-01
The study of infant vision is closely coupled to the study of the refraction, change in refraction over time, and the effect of spectacle correction on visual development. Frequently, reports are limited to descriptions of spherical equivalent or cylinder power without regard to axis, as data are frequently collected in the clinical format of sphere, cylinder, and axis (S, C, A). Conversion from clinical notation to a power vector representation of refraction allows unambiguous description of how refractions change over time and differ between repeated measurements. This article presents a series of examples of Microsoft Excel spreadsheet formulas that make the conversion from clinical notation to power vector format, and provides examples of useful applications of these methods.
Gene targeting with retroviral vectors
Energy Technology Data Exchange (ETDEWEB)
Ellis, J.; Bernstein, A. (Toronto Univ., ON (Canada))
1989-04-01
The authors have designed and constructed integration-defective retroviral vectors to explore their potential for gene targeting in mammalian cells. Two nonoverlapping deletion mutants of the bacterial neomycin resistance (neo) gene were used to detect homologous recombination events between viral and chromosomal sequences. Stable neo gene correction events were selected at a frequency of approximately 1 G418/sup r/ cell per 3 x 10/sup 6/ infected cells. Analysis of the functional neo gene in independent targeted cell clones indicated that unintegrated retroviral linear DNA recombined with the target by gene conversion for variable distances into regions of nonhomology. In addition, transient neo gene correction events which were associated with the complete loss of the chromosomal target sequences were observed. These results demonstrated that retroviral vectors can recombine with homologous chromosomal sequences in rodent and human cells.
ELVIS - ELectromagnetic Vector Information Sensor
Bergman, J E S; Thidé, B; Ananthakrishnan, S; Wahlund, J E; Karlsson, R L; Puccio, W; Carozzi, T D; Kale, P
2005-01-01
The ELVIS instrument was recently proposed by the authors for the Indian Chandrayaan-1 mission to the Moon and is presently under consideration by the Indian Space Research Organisation (ISRO). The scientific objective of ELVIS is to explore the electromagnetic environment of the moon. ELVIS samples the full three-dimensional (3D) electric field vector, E(x,t), up to 18 MHz, with selective Nyqvist frequency bandwidths down to 5 kHz, and one component of the magnetic field vector, B(x,t), from a few Hz up to 100 kHz.As a transient detector, ELVIS is capable of detecting pulses with a minimum pulse width of 5 ns. The instrument comprises three orthogonal electric dipole antennas, one magnetic search coil antenna and a four-channel digital sampling system, utilising flexible digital down conversion and filtering together with state-of-the-art onboard digital signal processing.
GAPS IN SUPPORT VECTOR OPTIMIZATION
Energy Technology Data Exchange (ETDEWEB)
STEINWART, INGO [Los Alamos National Laboratory; HUSH, DON [Los Alamos National Laboratory; SCOVEL, CLINT [Los Alamos National Laboratory; LIST, NICOLAS [Los Alamos National Laboratory
2007-01-29
We show that the stopping criteria used in many support vector machine (SVM) algorithms working on the dual can be interpreted as primal optimality bounds which in turn are known to be important for the statistical analysis of SVMs. To this end we revisit the duality theory underlying the derivation of the dual and show that in many interesting cases primal optimality bounds are the same as known dual optimality bounds.
Ultrasonic Dynamic Vector Stress Sensor
Heyman, Joseph S.; Froggatt, Mark
1992-01-01
Stress inferred from measurements in specimens rather than in bonded gauges. Ultrasonic dynamic vector stress sensor (UDVSS) measures changes in dynamic directional stress occurring in material or structure at location touched by device when material or structure put under cyclic load. Includes phase-locked loop, synchronous amplifier, and contact probe. Useful among manufacturers of aerospace and automotive structures for stress testing and evaluation of designs.
A ocean bottom vector magnetometer
Wang, Xiaomei; Teng, Yuntian; Wang, Chen; Ma, Jiemei
2017-04-01
The new development instrument with a compact spherical coil system and Overhauser magnetometer for measuring the total strength of the magnetic field and the vectors of strength, Delta inclination - Delta declination, meanwhile we also use a triaxial fluxgate instrument of the traditional instrument for geomagnetic vector filed measurement. The advantages of this method are be calibrated by each other and get good performances with automatic operation, good stability and high resolution. Firstly, a brief description of the instrument measurement principles and the key technologies are given. The instrument used a spherical coil system with 34 coils to product the homogeneous volume inside the coils which is large enough to accommodate the sensor of Overhauser total field sensor; the rest of the footlocker-sized ocean-bottom vector magnetometer consists of equipment to run the sensors and records its data (batteries and a data logger), weight to sink it to the sea floor, a remote-controlled acoustic release and flotation to bring the instrument back to the surface. Finally, the accuracy of the instrument was tested in the Geomagnetic station, and the measurement accuracies of total strength and components were better than 0.2nT and 1nT respectively. The figure 1 shows the development instrument structure. it includes six thick glass spheres which protect the sensor, data logger and batteries from the pressures of the deep sea, meanwhile they also provide recycling positive buoyancy; To cushion the glass, the spheres then go inside yellow plastic "hardhats". The triaxial fluxgate is inside No.1 glass spheres, data logger and batteries are inside No.2 glass spheres, the new vector sensor is inside No.3 glass spheres, acoustic communication unit is inside No.4 glass spheres, No.5 and No.6 glass spheres are empty which only provide recycling positive buoyancy. The figure 2 shows the development instrument Physical photo.
Biological rhythms and vector insects
Directory of Open Access Journals (Sweden)
Mirian David Marques
2013-01-01
Full Text Available The adjustment of all species, animals and plants, to the Earth’s cyclic environments is ensured by their temporal organisation. The relationships between parasites, vectors and hosts rely greatly upon the synchronisation of their biological rhythms, especially circadian rhythms. In this short note, parasitic infections by Protozoa and by microfilariae have been chosen as examples of the dependence of successful transmission mechanisms on temporal components.
Vector Fields and Flows on Differentiable Stacks
DEFF Research Database (Denmark)
A. Hepworth, Richard
2009-01-01
This paper introduces the notions of vector field and flow on a general differentiable stack. Our main theorem states that the flow of a vector field on a compact proper differentiable stack exists and is unique up to a uniquely determined 2-cell. This extends the usual result on the existence...... of vector fields....
Project Physics Programmed Instruction, Vectors 3.
Harvard Univ., Cambridge, MA. Harvard Project Physics.
This is the third of a series of three programmed instruction booklets on vectors developed by Harvard Project Physics. Separating vectors into components and obtaining a vector from its components are the topics covered. For other booklets in this series, see SE 015 549 and SE 015 550. (DT)
Vector and tensor analysis with applications
Borisenko, A I; Silverman, Richard A
1979-01-01
Concise and readable, this text ranges from definition of vectors and discussion of algebraic operations on vectors to the concept of tensor and algebraic operations on tensors. It also includes a systematic study of the differential and integral calculus of vector and tensor functions of space and time. Worked-out problems and solutions. 1968 edition.
Some Remarks on a Generalized Vector Product
Acosta-Humánez, Primitivo B; Núñez, Reinaldo
2011-01-01
In this paper we use a generalized vector product to construct an exterior form $\\wedge :(\\mathbb{R}^{n}) ^{k}\\to \\mathbb{R}^{\\binom{n}{k}}$, where $\\binom{n}{k}=\\frac{n!}{(n-k)!k!}$, $k\\leq n$. Finally, for $n=k-1$ we introduce the reversing operation to study this generalized vector product over palindromic and antipalindromic vectors.
On the Distribution of Norm of Vector Projection and Rejection of Two Complex Normal Random Vectors
Directory of Open Access Journals (Sweden)
Mehdi Maleki
2015-01-01
Full Text Available Vector projection and vector rejection are highly common and useful operations in mathematics, information theory, and signal processing. In this paper, we find the distribution of the norm of projection and rejection vectors when the original vectors are standard complex normally distributed.
Vectors and Rotations in 3-Dimensions: Vector Algebra for the C++ Programmer
2016-12-01
ARL-TR-7894•DEC 2016 US Army Research Laboratory Vectors and Rotations in 3-Dimensions:Vector Algebra for the C++ Programmer by Richard Saucier...Army Research Laboratory Vectors and Rotations in 3-Dimensions:Vector Algebra for the C++ Programmer by Richard Saucier Survivability/Lethality...
Wang, Shuo; Liu, Rui; Deng, Na; Liu, Yang; Wang, Haimin
2011-01-01
Photospheric magnetic field not only plays important roles in building up free energy and triggering solar eruptions, but also has been observed to change rapidly and permanently responding to the coronal magnetic field restructuring due to coronal transients. The Helioseismic and Magnetic Imager instrument (HMI) on board the newly launched Solar Dynamics Observatory (SDO) produces seeing-free full-disk vector magnetograms at consistently high resolution and high cadence, which finally makes possible an unambiguous and comprehensive study of this important back-reaction process. In this study, we present a near disk-center, GOES-class X2.2 flare occurred at NOAA AR 11158 on 2011 February 15 using the magnetic field measurements made by HMI. We obtained the first solid evidence of an enhancement in the transverse magnetic field at the flaring magnetic polarity inversion line (PIL) by a magnitude of 70%. This rapid and irreversible field evolution is unequivocally associated with the flare occurrence, with the ...
Problems and worked solutions in vector analysis
Shorter, LR
2014-01-01
""A handy book like this,"" noted The Mathematical Gazette, ""will fill a great want."" Devoted to fully worked out examples, this unique text constitutes a self-contained introductory course in vector analysis for undergraduate and graduate students of applied mathematics.Opening chapters define vector addition and subtraction, show how to resolve and determine the direction of two or more vectors, and explain systems of coordinates, vector equations of a plane and straight line, relative velocity and acceleration, and infinitely small vectors. The following chapters deal with scalar and vect
Solar activity monitoring and forecasting capabilities at Big Bear Solar Observatory
Directory of Open Access Journals (Sweden)
P. T. Gallagher
Full Text Available The availability of full-disk, high-resolution Ha images from Big Bear Solar Observatory (USA, Kanzelhöhe Solar Observatory (Austria, and Yunnan Astronomical Observatory (China allows for the continual monitoring of solar activity with unprecedented spatial and temporal resolution. Typically, this Global Ha Network (GHN provides almost uninterrupted Ha images with a cadence of 1 min and an image scale of 1'' per pixel.
Every hour, GHN images are transferred to the web-based BBSO Active Region Monitor (ARM; www.bbso.njit.edu/arm, which includes the most recent EUV, continuum, and magnetogram data from the Solar and Heliospheric Observatory, together with magnetograms from the Global Oscillation Network Group. ARM also includes a variety of active region properties from the National Oceanic and Atmospheric Administration’s Space Environment Center, such as up-to-date active region positions, GOES 5-min X-ray data, and flare identification. Stokes I, V, Q, and U images are available from the recently operational BBSO Digital Vector Magnetograph and the Vector Magnetograph at the Huairou Solar Observing Station of Beijing Observatory. Vector magnetograms provide complete information on the photospheric magnetic field, and allow for magnetic flux gradients, electric currents, and shear forces to be calculated: these measurements are extremely sensitive to conditions resulting in flaring activity. Furthermore, we have developed a Flare Prediction System which estimates the probability for each region to produce C-, M-, or X-class flares based on nearly eight years of NOAA data from cycle 22. This, in addition to BBSO’s daily solar activity reports, has proven a useful resource for activity forecasting.
Key words. Solar physics, astronomy and astrophysics (flares and mass ejections; instruments and techniques
DBSC-Based Grayscale Line Image Vectorization
Institute of Scientific and Technical Information of China (English)
Konstantin Melikhov; Feng Tian; Jie Qiu; Quan Chen; Hock Soon Seah
2006-01-01
Vector graphics plays an important role in computer animation and imaging technologies. However present techniques and tools cannot fully replace traditional pencil and paper. Additionally, vector representation of an image is not always available. There is not yet a good solution for vectorizing a picture drawn on a paper. This work attempts to solve the problem of vectorizing grayscale line drawings. The solution proposed uses Disk B-Spline curves to represent strokes of an image in vector form. The algorithm builds a vector representation from a grayscale raster image, which can be a scanned picture for instance. The proposed method uses a Gaussian sliding window to calculate skeleton and perceptive width of a stroke. As a result of vectorization, the given image is represented by a set of Disk B-Spline curves.
Transversals of Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
Dias, Kealey
, an important step was proving that the transversals possessed a certain characteristic. Understanding transversals might be the key to proving other polynomial vector fields are generic, and they are important in understanding bifurcations of polynomial vector fields in general. We consider two important......Vector fields in the complex plane are defined by assigning the vector determined by the value P(z) to each point z in the complex plane, where P is a polynomial of one complex variable. We consider special families of so-called rotated vector fields that are determined by a polynomial multiplied...... a concrete polynomial, it seems to take quite a bit of work to prove that it is generic, i.e. structurally stable. This has been done for a special class of degree d polynomial vector fields having simple equilibrium points at the d roots of unity, d odd. In proving that such vector fields are generic...
Transversals of Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
Dias, Kealey
by rotational constants. Transversals are a certain class of curves for such a family of vector fields that represent the bifurcation states for this family of vector fields. More specifically, transversals are curves that coincide with a homoclinic separatrix for some rotation of the vector field. Given......Vector fields in the complex plane are defined by assigning the vector determined by the value P(z) to each point z in the complex plane, where P is a polynomial of one complex variable. We consider special families of so-called rotated vector fields that are determined by a polynomial multiplied...... examples of rotated families to argue this. There will be discussed several open questions concerning the number of transversals that can appear for a certain degree d of a polynomial vector field, and furthermore how transversals are analyzed with respect to bifurcations around multiple equilibrium points....
The vector algebra war: A historical perspective
Chappell, James M; Hartnett, John G; Abbott, Derek
2015-01-01
There are a wide variety of different vector formalisms currently utilized in science. For example, Gibbs three-vectors, spacetime four-vectors, complex spinors for quantum mechanics, quaternions used for rigid body rotations and Clifford multivectors. With such a range of vector formalisms in use, it thus appears that there is as yet no general agreement on a vector formalism suitable for the whole of science. This surprising situation exists today, despite the fact that one of the main goals of nineteenth century science was to correctly describe vectors and the algebra of three-dimensional space. This situation has also had the unfortunate consequence of fragmenting knowledge across many disciplines and requiring a very significant amount of time and effort in learning the different formalisms. We thus review historically the development of our various vector systems and conclude that the Clifford algebra multivector fulfills the goal of correctly describing vectorial quantities in three dimensions.
Ravindra, B; Rangarajan, K E; Bagare, S P; Jagdev, Singh; Kemkar, P M M; Lancelot, J P; Thulasidharen, K C; Gabriel, F; Selvendran, R
2016-01-01
This paper reports on the installation and observations of a new solar telescope installed on 7th October, 2014 at the Kodaikanal Observatory. The telescope is a refractive type equipped with a tunable Lyot H$_{\\alpha}$ filter. A CCD camera of 2k$\\times$2k size makes the image of the Sun with a pixel size of 1.21$^{\\prime\\prime}$ pixel$^{-1}$ with a full field-of-view of 41$^{\\prime}$. The telescope is equipped with a guiding system which keeps the image of the Sun within a few pixels throughout the observations. The FWHM of the Lyot filter is 0.4\\AA~and the filter is motorized, capable of scanning the H$_{\\alpha}$ line profile at a smaller step size of 0.01\\AA. Partial-disk imaging covering about 10$^{\\prime}$, is also possible with the help of a relay lens kept in front of the CCD camera. In this paper, we report the detailed specifications of the telescope, filter unit, its installation, observations and the procedures we have followed to calibrate and align the data. We also present preliminary results wi...
Some theoretical comparisons of refined Ritz vectors and Ritz vectors
Institute of Scientific and Technical Information of China (English)
JIA Zhongxiao
2004-01-01
Refined projection methods proposed by the author have received attention internationally. We are concerned with a conventional projection method and its refined counterpart for computing approximations to a simple eigenpair (λ,x)of a large matrix A. Given a subspace w that contains anapproximation to x, these two methods compute approximations(μ(x~)) and (μ(x^)) to (λ,x),respectively. We establish three results. First, the refinedeigenvector approximation or simply the refined Ritz vector (x^) is unique as the deviation of x from w approaches zero if λ is simple. Second, interms of residual norm of the refined approximate eigenpair (μ,(x^)), we derive lower and upper bounds for the sine of the angle betweenthe Ritz vector (x~) and the refined eigenvector approximation (x^), and we prove that (x~)≠(x^) unless (x^)=x. Third, we establish relationships between theresidual norm ‖A(x~)-μ(x^)‖ of the conventionalmethods and the residual norm ‖A(x^)-μ(x^)‖ of therefined methods, and we show that the latter is always smallerthan the former if (μ,(x^)) is not an exact eigenpair ofA, indicating that the refined projection method is superiorto the corresponding conventional counterpart.
Some theoretical comparisons of refined Ritz vectors and Ritz vectors
Institute of Scientific and Technical Information of China (English)
JIA; Zhongxiao
2004-01-01
Refined projection methods proposed by the author have received attention internationally. We are concerned with a conventional projection method and its refined counterpart for computing approximations to a simple eigenpair (λ,x)of a large matrix A. Given a subspace w that contains anapproximation to x, these two methods compute approximations(μ(x~)) and (μ(x)) to (λ,x),respectively. We establish three results. First, the refinedeigenvector approximation or simply the refined Ritz vector (x) is unique as the deviation of x from w approaches zero if λ is simple. Second, interms of residual norm of the refined approximate eigenpair (μ,(x)), we derive lower and upper bounds for the sine of the angle betweenthe Ritz vector (x~) and the refined eigenvector approximation (x), and we prove that (x~)≠(x) unless (x)=x. Third, we establish relationships between theresidual norm ‖A(x~)-μ(x)‖ of the conventionalmethods and the residual norm ‖A(x)-μ(x)‖ of therefined methods, and we show that the latter is always smallerthan the former if (μ,(x)) is not an exact eigenpair ofA, indicating that the refined projection method is superiorto the corresponding conventional counterpart.
Vector meson electroproduction in QCD
Institute of Scientific and Technical Information of China (English)
LU Juan; CAI Xian-Hao; ZHOU Li-Juan
2012-01-01
Based on the generalized QCD vector meson dominance model,we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model.Numerical calculations for the total cross section σtot and differential cross section dσ/dt are performed for p,ω and φ meson electroproduction in this paper.Since gluons interact among themselves (self-interaction),two gluons can form a glueball with quantum numbers IG,JPC =0+,2++,decay width Γt ≈ 100 MeV,and mass of mG=2.23 GeV.The three gluons can form a three-gluon colorless bound state with charge conjugation quantum number C =-1,called the Odderon.The mediators of interactions between projectiles (the quark and antiquark pair fluctuated from the virtual photon) and the proton target (a three-quark system) are the tensor glueball and the Odderon.Our calculated results in the tensor glueball and Odderon exchange model fit to the existing data successfully,which evidently shows that our present QCD mechanism is a good description of meson electroproduction off a proton.It should be emphasized that our mechanism is different from the theoretical framework of Block et al.We also believe that the present study and its success are important for the investigation of other vector meson electro- and photoproduction at high energies,as well as for searching for new particles such as tensor glueballs and Odderons,which have been predicted by QCD and the color glass condensate model (CGC).Therefore,in return,it can test the validity of QCD and the CGC model.
Vector meson electroproduction in QCD
Lu, Juan; Cai, Xian-Hao; Zhou, Li-Juan
2012-08-01
Based on the generalized QCD vector meson dominance model, we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model. Numerical calculations for the total cross section σtot and differential cross section dσ/dt are performed for ρ, ω and varphi meson electroproduction in this paper. Since gluons interact among themselves (self-interaction), two gluons can form a glueball with quantum numbers IG, JPC = 0+,2++, decay width Γt ≈ 100 MeV, and mass of mG = 2.23 GeV. The three gluons can form a three-gluon colorless bound state with charge conjugation quantum number C = -1, called the Odderon. The mediators of interactions between projectiles (the quark and antiquark pair fluctuated from the virtual photon) and the proton target (a three-quark system) are the tensor glueball and the Odderon. Our calculated results in the tensor glueball and Odderon exchange model fit to the existing data successfully, which evidently shows that our present QCD mechanism is a good description of meson electroproduction off a proton. It should be emphasized that our mechanism is different from the theoretical framework of Block et al. We also believe that the present study and its success are important for the investigation of other vector meson electro- and photoproduction at high energies, as well as for searching for new particles such as tensor glueballs and Odderons, which have been predicted by QCD and the color glass condensate model (CGC). Therefore, in return, it can test the validity of QCD and the CGC model.
Nonviral Vectors for Gene Delivery
Baoum, Abdulgader Ahmed
2011-12-01
The development of nonviral vectors for safe and efficient gene delivery has been gaining considerable attention recently. An ideal nonviral vector must protect the gene against degradation by nuclease in the extracellular matrix, internalize the plasma membrane, escape from the endosomal compartment, unpackage the gene at some point and have no detrimental effects. In comparison to viruses, nonviral vectors are relatively easy to synthesize, less immunogenic, low in cost, and have no limitation in the size of a gene that can be delivered. Significant progress has been made in the basic science and applications of various nonviral gene delivery vectors; however, the majority of nonviral approaches are still inefficient and often toxic. To this end, two nonviral gene delivery systems using either biodegradable poly(D,L-lactide- co-glycolide) (PLG) nanoparticles or cell penetrating peptide (CPP) complexes have been designed and studied using A549 human lung epithelial cells. PLG nanoparticles were optimized for gene delivery by varying particle surface chemistry using different coating materials that adsorb to the particle surface during formation. A variety of cationic coating materials were studied and compared to more conventional surfactants used for PLG nanoparticle fabrication. Nanoparticles (˜200 nm) efficiently encapsulated plasmids encoding for luciferase (80-90%) and slowly released the same for two weeks. After a delay, moderate levels of gene expression appeared at day 5 for certain positively charged PLG particles and gene expression was maintained for at least two weeks. In contrast, gene expression mediated by polyethyleneimine (PEI) ended at day 5. PLG particles were also significantly less cytotoxic than PEI suggesting the use of these vehicles for localized, sustained gene delivery to the pulmonary epithelium. On the other hand, a more simple method to synthesize 50-200 nm complexes capable of high transfection efficiency or high gene knockdown was
On Weighted Support Vector Regression
DEFF Research Database (Denmark)
Han, Xixuan; Clemmensen, Line Katrine Harder
2014-01-01
We propose a new type of weighted support vector regression (SVR), motivated by modeling local dependencies in time and space in prediction of house prices. The classic weights of the weighted SVR are added to the slack variables in the objective function (OF‐weights). This procedure directly...... the differences and similarities of the two types of weights by demonstrating the connection between the Least Absolute Shrinkage and Selection Operator (LASSO) and the SVR. We show that an SVR problem can be transformed to a LASSO problem plus a linear constraint and a box constraint. We demonstrate...
Probability Ranking in Vector Spaces
Melucci, Massimo
2011-01-01
The Probability Ranking Principle states that the document set with the highest values of probability of relevance optimizes information retrieval effectiveness given the probabilities are estimated as accurately as possible. The key point of the principle is the separation of the document set into two subsets with a given level of fallout and with the highest recall. The paper introduces the separation between two vector subspaces and shows that the separation yields a more effective performance than the optimal separation into subsets with the same available evidence, the performance being measured with recall and fallout. The result is proved mathematically and exemplified experimentally.
Vector-tensor and vector-vector decay amplitude analysis of B0-->phiK*0.
Aubert, B; Bona, M; Boutigny, D; Couderc, F; Karyotakis, Y; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Grauges, E; Palano, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Gill, M S; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Pegna, D Lopes; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Sanchez, P del Amo; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schroeder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Asgeirsson, D J; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Sherwood, D J; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Best, D S; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Roethel, W; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Hadavand, H K; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Cheng, C H; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Thiebaux, Ch; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Vetere, M Lo; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Brandenburg, G; Chaisanguanthum, K S; Lee, C L; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Nash, J A; Nikolich, M B; Vazquez, W Panduro; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y; Gritsan, A V; Guo, Z J; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Diberder, F Le; Lutz, A M; Oyanguren, A; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; Clarke, C K; Lodovico, F Di; Menges, W; Sacco, R; Cowan, G; Flaecher, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; Naisbit, M T; Williams, J C; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Saremi, S; Staengle, H; Cowan, R; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; McLachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; Nardo, G De; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; Losecco, J M; Benelli, G; Corwin, L A; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Rahimi, A M; Regensburger, J J; Ter-Antonyan, R; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Potter, C T; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; Buono, L Del; de la Vaissière, Ch; Hamon, O; Hartfiel, B L; Leruste, Ph; Malclès, J; Ocariz, J; Roos, L; Therin, G; Gladney, L; Biasini, M; Covarelli, R; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; del Re, D; Marco, E Di; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Gioi, L Li; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Tehrani, F Safai; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; Franek, B; Olaiya, E O; Ricciardi, S; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; de Monchenault, G Hamel; Kozanecki, W; Legendre, M; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Leith, D W G S; Li, S; Luitz, S; Luth, V; Lynch, H L; Macfarlane, D B; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Wagner, A P; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wittgen, M; Wright, D H; Wulsin, H W; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Ricca, G Della; Dittongo, S; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Banerjee, Sw; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Flood, K T; Hollar, J J; Kutter, P E; Mellado, B; Mihalyi, A; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Yu, Z; Neal, H
2007-02-02
We perform an amplitude analysis of the decays B(0)-->phiK*(2)(1430)(0), phiK*(892)(0), and phi(Kpi)(0)(S-wave) with a sample of about 384x10(6) BB[over ] pairs recorded with the BABAR detector. The fractions of longitudinal polarization f(L) of the vector-tensor and vector-vector decay modes are measured to be 0.853(-0.069+0.061)+/-0.036 and 0.506+/-0.040+/-0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP violation.
Current progress of polymeric gene vectors
Institute of Scientific and Technical Information of China (English)
ZENG Xuan; SUN YunXia; ZHUO RenXi; ZHANG XianZheng
2011-01-01
After over 40 years ot progress,gene therapy provides great opportunities for treating diseases from various genetic disorders,infections and cancers.The success of gene therapy largely depends on the availability of suitable gene vectors.As an attractive alternative to virus-based gene therapy,non-viral gene delivery system has been developed and investigated due to their merits including low immunogenecity,convenient operability,and large-scale manufacturability [1].Because polycations can condense with DNA as a result of electrostatic interactions,form nanosize polyplexes,and protect DNA from degradation by DNase,cationic polymer becomes a major type of non-viral gene delivery vectors (Figure 1) [2].A wide range of polymeric vectors have been developed and investigated in the past decade,such as polyethylenimine (PEI)-based vectors,poly(L-lysine) (PLL)-based vectors,dendrimer-based vectors,polypeptide-based vectors,and chitosan-based vectors [3].However,unlike viral vectors that have the ability to infect host cells and overcome cellular barriers through the course of evolution,nonviral gene vectors exhibit Significantly reduced transfection efficiency as they are obstructed by various extra- and intracellular barriers,including serum proteins in blood stream,cell membrane,endosomal compartment and nuclear membrane [4].
Therapeutic and prophylactic applications of alphavirus vectors.
Atkins, Gregory J; Fleeton, Marina N; Sheahan, Brian J
2008-11-11
Alphavirus vectors are high-level, transient expression vectors for therapeutic and prophylactic use. These positive-stranded RNA vectors, derived from Semliki Forest virus, Sindbis virus and Venezuelan equine encephalitis virus, multiply and are expressed in the cytoplasm of most vertebrate cells, including human cells. Part of the genome encoding the structural protein genes, which is amplified during a normal infection, is replaced by a transgene. Three types of vector have been developed: virus-like particles, layered DNA-RNA vectors and replication-competent vectors. Virus-like particles contain replicon RNA that is defective since it contains a cloned gene in place of the structural protein genes, and thus are able to undergo only one cycle of expression. They are produced by transfection of vector RNA, and helper RNAs encoding the structural proteins. Layered DNA-RNA vectors express the Semliki Forest virus replicon from a cDNA copy via a cytomegalovirus promoter. Replication-competent vectors contain a transgene in addition to the structural protein genes. Alphavirus vectors are used for three main applications: vaccine construction, therapy of central nervous system disease, and cancer therapy.
Vector-Resonance-Multimode Instability
Sergeyev, S. V.; Kbashi, H.; Tarasov, N.; Loiko, Yu.; Kolpakov, S. A.
2017-01-01
The modulation and multimode instabilities are the main mechanisms which drive spontaneous spatial and temporal pattern formation in a vast number of nonlinear systems ranging from biology to laser physics. Using an Er-doped fiber laser as a test bed, here for the first time we demonstrate both experimentally and theoretically a new type of a low-threshold vector-resonance-multimode instability which inherits features of multimode and modulation instabilities. The same as for the multimode instability, a large number of longitudinal modes can be excited without mode synchronization. To enable modulation instability, we modulate the state of polarization of the lasing signal with the period of the beat length by an adjustment of the in-cavity birefringence and the state of polarization of the pump wave. As a result, we show the regime's tunability from complex oscillatory to periodic with longitudinal mode synchronization in the case of resonance matching between the beat and cavity lengths. Apart from the interest in laser physics for unlocking the tunability and stability of dynamic regimes, the proposed mechanism of the vector-resonance-multimode instability can be of fundamental interest for the nonlinear dynamics of various distributed systems.
Adam, C; Sanchez-Guillen, J; Wereszczynski, A
2012-01-01
We analyze the vector meson formulation of the BPS Skyrme model in (3+1) dimensions, where the term of sixth power in first derivatives characteristic for the original, integrable BPS Skyrme model (the topological or baryon current squared) is replaced by a coupling between the vector meson $\\omega_\\mu$ and the baryon current. We find that the model remains integrable in the sense of generalized integrability and almost solvable (reducible to a set of two first order ODEs) for any value of the baryon charge. Further, we analyze the appearance of topological solitons for two one-parameter families of one vacuum potentials: the old Skyrme potentials and the so-called BPS potentials. Depending on the value of the parameters we find several qualitatively different possibilities. In the massless case we have a parameter region with no skyrmions, a unique compact skyrmion with a discontinuous first derivative at the boundary (equivalently, with a source term located at the boundary, which screens the topological ch...
A Modified Moist Ageostrophic Q Vector
Institute of Scientific and Technical Information of China (English)
YUE Caijun; SHOU Shaowen
2008-01-01
The quasi-geostrophic Q vector is an important diagnostic tool for studying development of surface rainfall associated with large-scale weather systems and is calculated using data at single vertical level. When ageostrophic Q vector was introduced, it required data at two vertical levels. In this study, moist ageostrophic Q vector is modified so that it can be calculated using data at a single vertical level. The comparison study between the original and modified moist ageostrophic Q vectors is conducted using the data from 5 to 6 July 1991 during the torrential rainfall event associated with the Changjiang-Huaihe mei-yu front in China. The results reveal that divergences of original and modified moist ageostrophic Q vectors have similar horizontal distributions and their centers are almost located in the precipitation centers. This indicates that modified moist ageostrophic Q vector can be used to diagnose convective development with reasonable accuracy.
Vector assembly of colloids on monolayer substrates
Jiang, Lingxiang; Yang, Shenyu; Tsang, Boyce; Tu, Mei; Granick, Steve
2017-06-01
The key to spontaneous and directed assembly is to encode the desired assembly information to building blocks in a programmable and efficient way. In computer graphics, raster graphics encodes images on a single-pixel level, conferring fine details at the expense of large file sizes, whereas vector graphics encrypts shape information into vectors that allow small file sizes and operational transformations. Here, we adapt this raster/vector concept to a 2D colloidal system and realize `vector assembly' by manipulating particles on a colloidal monolayer substrate with optical tweezers. In contrast to raster assembly that assigns optical tweezers to each particle, vector assembly requires a minimal number of optical tweezers that allow operations like chain elongation and shortening. This vector approach enables simple uniform particles to form a vast collection of colloidal arenes and colloidenes, the spontaneous dissociation of which is achieved with precision and stage-by-stage complexity by simply removing the optical tweezers.
Integrated epidemiology for vector-borne zoonoses
2016-01-01
The development and application of interventions for the control of vector-borne zoonoses requires broad understanding of epidemiological linkages between vector, animal infection and human infection. However, there are significant gaps in our understanding of these linkages and a lack of appropriate data poses a considerable barrier to addressing this issue. A move towards strengthened surveillance of vectors and disease in both animal and human hosts, in combination with linked human-animal...
Higgs Decays and Brane Gravi-vectors
Clark, T. E.; Liu, B. Y.; Love, S. T.; Xiong, C.; ter Veldhuis, T.
2008-01-01
Higgs boson decays in flexible brane world models with stable, massive gravi-vectors are considered. Such vectors couple bilinearly to the Standard Model fields through either the Standard Model energy-momentum tensor, the weak hypercharge field strength or the Higgs scalar. The role of the coupling involving the extrinsic curvature is highlighted. It is found that within the presently allowed parameter space, the decay rate of the Higgs into two gravi-vectors (which would appear as an invisi...
[Research progress on malaria vector control].
Zhu, Guo-Ding; Cao, Jun; Zhou, Hua-Yun; Gao, Qi
2013-06-01
Vector control plays a crucial role in the stages of malaria control and elimination. Currently, it mainly relies on the chemical control methods for adult mosquitoes in malaria endemic areas, however, it is undergoing the serious threat by insecticide resistance. In recent years, the transgenic technologies of malaria vectors have made a great progress in the laboratory. This paper reviews the challenges of the traditional methods and the rapid developed genetic modified technology in the application of vector control.
Construction of shRNA lentiviral vector
Directory of Open Access Journals (Sweden)
Hong Song
2010-12-01
Full Text Available Lentiviruses have been adapted as gene delivery vehicles. This article summarized shRNA lentiviral vector methods generally used in research laboratories. The main procedures of shRNA lentiviral vector include that (1 Target sequences screening and shRNA oligonucleotides designing, (2 insert designed oligonucleotides into lentiviral vectors, (3 using packaging cells to produce shRNA lentivirus, and (4 transducing target cells with shRNA lentivirus.
Genetic manipulation of endosymbionts to control vector and vector borne diseases
Directory of Open Access Journals (Sweden)
Jay Prakash Gupta
Full Text Available Vector borne diseases (VBD are on the rise because of failure of the existing methods of control of vector and vector borne diseases and the climate change. A steep rise of VBDs are due to several factors like selection of insecticide resistant vector population, drug resistant parasite population and lack of effective vaccines against the VBDs. Environmental pollution, public health hazard and insecticide resistant vector population indicate that the insecticides are no longer a sustainable control method of vector and vector-borne diseases. Amongst the various alternative control strategies, symbiont based approach utilizing endosymbionts of arthropod vectors could be explored to control the vector and vector borne diseases. The endosymbiont population of arthropod vectors could be exploited in different ways viz., as a chemotherapeutic target, vaccine target for the control of vectors. Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting arthropods may serve as a powerful approach to control certain arthropod-borne diseases. Genetic transformation of symbiotic bacteria of the arthropod vector to alter the vector’s ability to transmit pathogen is an alternative means of blocking the transmission of VBDs. In Indian scenario, where dengue, chikungunya, malaria and filariosis are prevalent, paratransgenic based approach can be used effectively. [Vet World 2012; 5(9.000: 571-576
Pro jective vector fields on Finsler manifolds
Institute of Scientific and Technical Information of China (English)
TIAN Huang-jia
2014-01-01
In this paper, we give the equation that characterizes projective vector fields on a Finsler manifold by the local coordinate. Moreover, we obtain a feature of the projective fields on the compact Finsler manifold with non-positive flag curvature and the non-existence of projective vector fields on the compact Finsler manifold with negative flag curvature. Furthermore, we deduce some expectable, but non-trivial relationships between geometric vector fields such as projective, affine, conformal, homothetic and Killing vector fields on a Finsler manifold.
A New Incremental Support Vector Machine Algorithm
Directory of Open Access Journals (Sweden)
Wenjuan Zhao
2012-10-01
Full Text Available Support vector machine is a popular method in machine learning. Incremental support vector machine algorithm is ideal selection in the face of large learning data set. In this paper a new incremental support vector machine learning algorithm is proposed to improve efficiency of large scale data processing. The model of this incremental learning algorithm is similar to the standard support vector machine. The goal concept is updated by incremental learning. Each training procedure only includes new training data. The time complexity is independent of whole training set. Compared with the other incremental version, the training speed of this approach is improved and the change of hyperplane is reduced.
Vector perturbations of galaxy number counts
Durrer, Ruth; Tansella, Vittorio
2016-07-01
We derive the contribution to relativistic galaxy number count fluctuations from vector and tensor perturbations within linear perturbation theory. Our result is consistent with the the relativistic corrections to number counts due to scalar perturbation, where the Bardeen potentials are replaced with line-of-sight projection of vector and tensor quantities. Since vector and tensor perturbations do not lead to density fluctuations the standard density term in the number counts is absent. We apply our results to vector perturbations which are induced from scalar perturbations at second order and give numerical estimates of their contributions to the power spectrum of relativistic galaxy number counts.
Vector perturbations of galaxy number counts
Durrer, Ruth
2016-01-01
We derive the contribution to relativistic galaxy number count fluctuations from vector and tensor perturbations within linear perturbation theory. Our result is consistent with the the relativistic corrections to number counts due to scalar perturbation, where the Bardeen potentials are replaced with line-of-sight projection of vector and tensor quantities. Since vector and tensor perturbations do not lead to density fluctuations the standard density term in the number counts is absent. We apply our results to vector perturbations which are induced from scalar perturbations at second order and give numerical estimates of their contributions to the power spectrum of relativistic galaxy number counts.
Directory of Open Access Journals (Sweden)
Chuan-Ren Chen
2015-02-01
Full Text Available Even though the sensitivity of direct dark matter search experiments reaches the level of about 10−45 cm2, no confident signal of dark matter has been observed. We point out that, if dark matter is a vector boson, the null result in direct dark matter search experiments may be due to the destructive effects in dark-matter–nucleon elastic scattering. We illustrate the scenario using a modified Higgs portal model that includes exotic quarks. The significant cancellation can occur for a certain mass gap between new heavy quark and dark matter. As a result, the spin-independent dark-matter–nucleon elastic scattering is so suppressed that the future direct search experiments will hardly observe the signal of dark matter.
Synthetic Aperture Vector Flow Imaging
DEFF Research Database (Denmark)
Villagómez Hoyos, Carlos Armando
The main objective of this project was to continue the development of a synthetic aperture vector flow estimator. This type of estimator is capable of overcoming two of the major limitations in conventional ultrasound systems: 1) the inability to scan large region of interest with high temporal...... resolutions; 2) the lack of capability in detecting flow other than the one along the direction of the beam. Addressing these technical limitations would translate in the clinic as a gain in valuable clinical information and a removal of operator-dependant sources of error, which would improve the diagnosis....... The main contribution of this work was the development of an angle estimator which features high accuracy and low standard deviation over the full 360◦ range. The estimator demonstrated its capability of operating at high frame rates (> 1000 Hz), and simultaneously detecting a large range of flow...
Differentially Private Support Vector Machines
Sarwate, Anand; Monteleoni, Claire
2009-01-01
This paper addresses the problem of practical privacy-preserving machine learning: how to detect patterns in massive, real-world databases of sensitive personal information, while maintaining the privacy of individuals. Chaudhuri and Monteleoni (2008) recently provided privacy-preserving techniques for learning linear separators via regularized logistic regression. With the goal of handling large databases that may not be linearly separable, we provide privacy-preserving support vector machine algorithms. We address general challenges left open by past work, such as how to release a kernel classifier without releasing any of the training data, and how to tune algorithm parameters in a privacy-preserving manner. We provide general, efficient algorithms for linear and nonlinear kernel SVMs, which guarantee $\\epsilon$-differential privacy, a very strong privacy definition due to Dwork et al. (2006). We also provide learning generalization guarantees. Empirical evaluations reveal promising performance on real and...
Introduction to Vector Field Visualization
Kao, David; Shen, Han-Wei
2010-01-01
Vector field visualization techniques are essential to help us understand the complex dynamics of flow fields. These can be found in a wide range of applications such as study of flows around an aircraft, the blood flow in our heart chambers, ocean circulation models, and severe weather predictions. The vector fields from these various applications can be visually depicted using a number of techniques such as particle traces and advecting textures. In this tutorial, we present several fundamental algorithms in flow visualization including particle integration, particle tracking in time-dependent flows, and seeding strategies. For flows near surfaces, a wide variety of synthetic texture-based algorithms have been developed to depict near-body flow features. The most common approach is based on the Line Integral Convolution (LIC) algorithm. There also exist extensions of LIC to support more flexible texture generations for 3D flow data. This tutorial reviews these algorithms. Tensor fields are found in several real-world applications and also require the aid of visualization to help users understand their data sets. Examples where one can find tensor fields include mechanics to see how material respond to external forces, civil engineering and geomechanics of roads and bridges, and the study of neural pathway via diffusion tensor imaging. This tutorial will provide an overview of the different tensor field visualization techniques, discuss basic tensor decompositions, and go into detail on glyph based methods, deformation based methods, and streamline based methods. Practical examples will be used when presenting the methods; and applications from some case studies will be used as part of the motivation.
Vector optimization set-valued and variational analysis
Chen, Guang-ya; Yang, Xiaogi
2005-01-01
This book is devoted to vector or multiple criteria approaches in optimization. Topics covered include: vector optimization, vector variational inequalities, vector variational principles, vector minmax inequalities and vector equilibrium problems. In particular, problems with variable ordering relations and set-valued mappings are treated. The nonlinear scalarization method is extensively used throughout the book to deal with various vector-related problems. The results presented are original and should be interesting to researchers and graduates in applied mathematics and operations research
Haydar, Deniz; Wolff, Wim J.
2011-01-01
Oyster transports are among the leading anthropogenic vectors of coastwise introduction of non-indigenous species. Using the oyster industry of the Netherlands as a model system, we investigated the relationship between vector strength (number of invasions) and vector tempo (magnitude and frequency
CLASSIFICATION OF CUBIC PARAMETERIZED HOMOGENEOUS VECTOR FIELDS
Institute of Scientific and Technical Information of China (English)
Karnal H.Yasir; TANG Yun
2002-01-01
In this paper the cubic homogeneous parameterized vector fields are studied.The classification of the phase portrait near the critical point is presented. This classification is an extension of the result given by Takens to the cubic homogeneous parameterized vector fields with six parameters.
CLASSIFICATION OF CUBIC PARAMETERIZED HOMOGENEOUS VECTOR FIELDS
Institute of Scientific and Technical Information of China (English)
KamalH.Yasir; TNAGYun
2002-01-01
In this paper the cubic homogeneous parameterized vector fields are studied.The classification of the phase portrait near the critical point is presented.This classification is an extension of the result given by takens to the cubic homogeneous parameterized vector fields with six parameters.
2010-07-01
... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Vectors. 240.206 Section 240.206 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE THERMAL PROCESSING OF SOLID WASTES Requirements and Recommended Procedures § 240.206 Vectors....
A Survey on Distance Vector Routing Protocols
Tang, Linpeng
2011-01-01
In this paper we give a brief introduction to five different distance vector routing protocols (RIP, AODV, EIGRP, RIP-MTI and Babel) and give some of our thoughts on how to solve the count to infinity problem. Our focus is how distance vector routing protocols, based on limited information, can prevent routing loops and the count to infinity problem.
Nonlinear dynamics of a vectored thrust aircraft
DEFF Research Database (Denmark)
Sørensen, C.B; Mosekilde, Erik
1996-01-01
With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three...
Chiral Corrections to Vector Meson Decay Constants
Bijnens, J; Talavera, P; Bijnens, Johan; Gosdzinsky, Peter; Talavera, Pere
1998-01-01
We calculate the leading quark mass corrections of order $m_q\\log(m_q)$, $m_q$ and $m_q^{3/2}$ to the vector meson decay constants within Heavy Vector Meson Chiral Perturbation Theory. We discuss the issue of electromagnetic gauge invariance and the heavy mass expansion. Reasonably good fits to the observed decay constants are obtained.
Nonlinear dynamics of a vectored thrust aircraft
DEFF Research Database (Denmark)
Sørensen, C.B; Mosekilde, Erik
1996-01-01
With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three ...
Deep Support Vector Machines for Regression Problems
Wiering, Marco; Schutten, Marten; Millea, Adrian; Meijster, Arnold; Schomaker, Lambertus
2013-01-01
In this paper we describe a novel extension of the support vector machine, called the deep support vector machine (DSVM). The original SVM has a single layer with kernel functions and is therefore a shallow model. The DSVM can use an arbitrary number of layers, in which lower-level layers contain su
Application of Vectors to Relative Velocity
Tin-Lam, Toh
2004-01-01
The topic 'relative velocity' has recently been introduced into the Cambridge Ordinary Level Additional Mathematics syllabus under the application of Vectors. In this note, the results of relative velocity and the 'reduction to rest' technique of teaching relative velocity are derived mathematically from vector algebra, in the hope of providing…
Articulated Multimedia Physics, Lesson 4, Vectors.
New York Inst. of Tech., Old Westbury.
As the fourth lesson of the Articulated Multimedia Physics Course, instructional materials are presented in this study guide. The subject matter is concerned with displacements, speeds, scalers, vector sum, and vector analysis.The content is arranged in scrambled form, and the use of matrix transparencies is required for students to control their…
Vector-Quantization using Information Theoretic Concepts
DEFF Research Database (Denmark)
Lehn-Schiøler, Tue; Hegde, Anant; Erdogmus, Deniz
2005-01-01
The process of representing a large data set with a smaller number of vectors in the best possible way, also known as vector quantization, has been intensively studied in the recent years. Very efficient algorithms like the Kohonen Self Organizing Map (SOM) and the Linde Buzo Gray (LBG) algorithm...
Clustering Categories in Support Vector Machines
DEFF Research Database (Denmark)
Carrizosa, Emilio; Nogales-Gómez, Amaya; Morales, Dolores Romero
2017-01-01
The support vector machine (SVM) is a state-of-the-art method in supervised classification. In this paper the Cluster Support Vector Machine (CLSVM) methodology is proposed with the aim to increase the sparsity of the SVM classifier in the presence of categorical features, leading to a gain in in...
Increasing the Efficacy of Oncolytic Adenovirus Vectors
Directory of Open Access Journals (Sweden)
William S. M. Wold
2010-08-01
Full Text Available Oncolytic adenovirus (Ad vectors present a new modality to treat cancer. These vectors attack tumors via replicating in and killing cancer cells. Upon completion of the vector replication cycle, the infected tumor cell lyses and releases progeny virions that are capable of infecting neighboring tumor cells. Repeated cycles of vector replication and cell lysis can destroy the tumor. Numerous Ad vectors have been generated and tested, some of them reaching human clinical trials. In 2005, the first oncolytic Ad was approved for the treatment of head-and-neck cancer by the Chinese FDA. Oncolytic Ads have been proven to be safe, with no serious adverse effects reported even when high doses of the vector were injected intravenously. The vectors demonstrated modest anti-tumor effect when applied as a single agent; their efficacy improved when they were combined with another modality. The efficacy of oncolytic Ads can be improved using various approaches, including vector design, delivery techniques, and ancillary treatment, which will be discussed in this review.
Vector Spaces of Non-measurable Functions
Institute of Scientific and Technical Information of China (English)
Francisco J. GARC(I)A-PACHECO; Juan B. SEOANE-SEP(U)LVEDA
2006-01-01
We show that there exists an infinite dimensional vector space every non-zero element of which is a non-measurable function. Moreover, this vector space can be chosen to be closed and to have dimensionβ for any cardinalityβ. Some techniques involving measure theory and density characters of Banach spaces are used.
Diffeomorphism Invariant Theories and Vector Supersymmetry
Piguet, O
2000-01-01
Einstein gravity in the Palatini first order formalism is shown to possess a vector supersymmetry of the type encountered in the topological gauge theories. A peculiar feature of the gravitationel theory is the link of this vector supersymmetry with the field equation of motion of the Faddeev-Popov ghost associated to diffeomorphism invariance.
Deep Support Vector Machines for Regression Problems
Wiering, Marco; Schutten, Marten; Millea, Adrian; Meijster, Arnold; Schomaker, Lambertus
2013-01-01
In this paper we describe a novel extension of the support vector machine, called the deep support vector machine (DSVM). The original SVM has a single layer with kernel functions and is therefore a shallow model. The DSVM can use an arbitrary number of layers, in which lower-level layers contain
Clifford Fourier transform on vector fields.
Ebling, Julia; Scheuermann, Gerik
2005-01-01
Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space.
Cascade Support Vector Machines with Dimensionality Reduction
Directory of Open Access Journals (Sweden)
Oliver Kramer
2015-01-01
Full Text Available Cascade support vector machines have been introduced as extension of classic support vector machines that allow a fast training on large data sets. In this work, we combine cascade support vector machines with dimensionality reduction based preprocessing. The cascade principle allows fast learning based on the division of the training set into subsets and the union of cascade learning results based on support vectors in each cascade level. The combination with dimensionality reduction as preprocessing results in a significant speedup, often without loss of classifier accuracies, while considering the high-dimensional pendants of the low-dimensional support vectors in each new cascade level. We analyze and compare various instantiations of dimensionality reduction preprocessing and cascade SVMs with principal component analysis, locally linear embedding, and isometric mapping. The experimental analysis on various artificial and real-world benchmark problems includes various cascade specific parameters like intermediate training set sizes and dimensionalities.
Low-amplitude vector screening solitons
Institute of Scientific and Technical Information of China (English)
Keqing Lu(卢克清); Xiangping Zhu(朱香平); Wei Zhao(赵卫); Yanlong Yang(杨延龙); Jinping Li(李金萍); Yanpeng Zhang(张彦鹏); Junchang Zhang(张君昌)
2004-01-01
We show self-coupled and cross-coupled vector beam evolution equations in the low-amplitude regime for screening solitons,which can exhibit the analytical solutions of bright-bright and dark-dark vector solitons.Our analysis indicates that these self-coupled vector solitons are obtained irrespective of the intensities of the two optical beams,whereas these cross-coupled vector solitons can be established when the intensities of the two optical beams are equal.Relevant examples are provided where the photorefractive crystal is lithium niobate(LiNbO3).The stability properties of these vector solitons have been investigated numerically and it has been found that they are stable.
Vector Diffusion Maps and the Connection Laplacian
Singer, Amit
2011-01-01
We introduce {\\em vector diffusion maps} (VDM), a new mathematical framework for organizing and analyzing massive high dimensional data sets, images and shapes. VDM is a mathematical and algorithmic generalization of diffusion maps and other non-linear dimensionality reduction methods, such as LLE, ISOMAP and Laplacian eigenmaps. While existing methods are either directly or indirectly related to the heat kernel for functions over the data, VDM is based on the heat kernel for vector fields. VDM provides tools for organizing complex data sets, embedding them in a low dimensional space, and interpolating and regressing vector fields over the data. In particular, it equips the data with a metric, which we refer to as the {\\em vector diffusion distance}. In the manifold learning setup, where the data set is distributed on (or near) a low dimensional manifold $\\MM^d$ embedded in $\\RR^{p}$, we prove the relation between VDM and the connection-Laplacian operator for vector fields over the manifold.
Alphavirus vectors for cancer gene therapy (review).
Yamanaka, Ryuya
2004-04-01
Alphaviruses have several characteristics that make them attractive as gene therapy vectors such as transient and high-level expression of a heterologous gene. Alphavirus vectors, Semliki Forest virus (SFV), Sindbis virus (SIN) and Venezuelan equine encephalitis virus (VEE) have been developed as gene expression vectors. Alphaviruses are positive-strand RNA viruses that can mediate efficient cytoplasmic gene expression in mammalian cells. The alphavirus RNA replication machinery has been engineered for high level heterologous gene expression. Since an RNA virus vector cannot integrate into chromosomal DNA, concerns about cell transformation are reduced. Alphavirus vectors demonstrate promise for the safe tumor-killing and tumor-specific immune responses. Recombinant alphavirus RNA replicons may facilitate gene therapy of cancer.
Axial Vector $Z'$ and Anomaly Cancellation
Ismail, Ahmed; Tsao, Kuo-Hsing; Unwin, James
2016-01-01
Whilst the prospect of new $Z'$ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that the masses of these new states must generally be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.
Axial vector Z‧ and anomaly cancellation
Ismail, Ahmed; Keung, Wai-Yee; Tsao, Kuo-Hsing; Unwin, James
2017-05-01
Whilst the prospect of new Z‧ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that in a large class of models masses of these new states are expected to be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.
Gauge vectors and double beta decay
Fonseca, Renato M.; Hirsch, Martin
2017-02-01
We discuss contributions to neutrinoless double beta (0 ν β β ) decay involving vector bosons. The starting point is a list of all possible vector representations that may contribute to 0 ν β β decay via d =9 or d =11 operators at tree level. We then identify gauge groups which contain these vectors in the adjoint representation. Even though the complete list of vector fields that can contribute to 0 ν β β up to d =11 is large (a total of 46 vectors), only a few of them can be gauge bosons of phenomenologically realistic groups. These latter cases are discussed in some more detail, and lower (upper) limits on gauge boson masses (mixing angles) are derived from the absence of 0 ν β β decay.
Geoacoustic inversion using the vector field
Crocker, Steven E.
The main goal of this project was to study the use of the acoustic vector field, separately or in combination with the scalar field, to estimate the depth dependent geoacoustic properties of the seafloor via non-linear inversion. The study was performed in the context of the Sediment Acoustics Experiment 2004 (SAX04) conducted in the Northern Gulf of Mexico (GOM) where a small number of acoustic vector sensors were deployed in close proximity to the seafloor. A variety of acoustic waveforms were transmitted into the seafloor at normal incidence. The acoustic vector sensors were located both above and beneath the seafloor interface where they measured the acoustic pressure and the acoustic particle acceleration. Motion data provided by the buried vector sensors were affected by a suspension response that was sensitive to the mass properties of the sensor, the sediment density and sediment elasticity (e.g., shear wave speed). The suspension response for the buried vector sensors included a resonance within the analysis band of 0.4 to 2.0 kHz. The suspension resonance represented an unknown complex transfer function between the acoustic vector field in the seabed and data representing that field. Therefore, inverse methods developed for this study were required to 1) estimate dynamic properties of the sensor suspension resonance and 2) account for the associated corruption of vector field data. A method to account for the vector sensor suspense response function was integrated directly into the inversion methods such that vector channel data corruption was reduced and an estimate of the shear wave speed in the sediment was returned. Inversions of real and synthetic data sets indicated that information about sediment shear wave speed was carried by the suspension response of the buried sensors, as opposed to being contained inherently within the acoustic vector field.
Image Coding Based on Address Vector Quantization.
Feng, Yushu
Image coding is finding increased application in teleconferencing, archiving, and remote sensing. This thesis investigates the potential of Vector Quantization (VQ), a relatively new source coding technique, for compression of monochromatic and color images. Extensions of the Vector Quantization technique to the Address Vector Quantization method have been investigated. In Vector Quantization, the image data to be encoded are first processed to yield a set of vectors. A codeword from the codebook which best matches the input image vector is then selected. Compression is achieved by replacing the image vector with the index of the code-word which produced the best match, the index is sent to the channel. Reconstruction of the image is done by using a table lookup technique, where the label is simply used as an address for a table containing the representative vectors. A code-book of representative vectors (codewords) is generated using an iterative clustering algorithm such as K-means, or the generalized Lloyd algorithm. A review of different Vector Quantization techniques are given in chapter 1. Chapter 2 gives an overview of codebook design methods including the Kohonen neural network to design codebook. During the encoding process, the correlation of the address is considered and Address Vector Quantization is developed for color image and monochrome image coding. Address VQ which includes static and dynamic processes is introduced in chapter 3. In order to overcome the problems in Hierarchical VQ, Multi-layer Address Vector Quantization is proposed in chapter 4. This approach gives the same performance as that of the normal VQ scheme but the bit rate is about 1/2 to 1/3 as that of the normal VQ method. In chapter 5, a Dynamic Finite State VQ based on a probability transition matrix to select the best subcodebook to encode the image is developed. In chapter 6, a new adaptive vector quantization scheme, suitable for color video coding, called "A Self -Organizing
Petrie, Gordon; McMaken, Tyler C.
2017-08-01
The solar active region (AR), NOAA 12192, appeared in 2014 October as the largest AR in 24 years. Here we examine the counterintuitive nature of two diffusion-driven processes in the region: the role of helicity buildup in the formation of a major filament, and the relationship between the effects of supergranular diffusion and meridional flow on the AR and on the polar field. Quantitatively, calculations of current helicity and magnetic twist from Helioseismic and Magnetic Imager (HMI) vector magnetograms indicate that, though AR 12192 emerged with negative helicity, positive helicity from subsequent flux emergence, consistent with the hemispheric sign-preference of helicity, increased over time within large-scale, weak-field regions such as those near the polarity inversion line (PIL). Morphologically, Atmospheric Imaging Assembly observations of filament barbs, sigmoidal patterns, and bases of Fe xii stalks initially exhibited signatures of negative helicity, and the long filament that subsequently formed had a strong positive helicity consistent with the helicity buildup along the PIL. We find from full-disk HMI magnetograms that AR 12192's leading positive flux was initially closer to the equator but, owing either to the region’s magnetic surroundings or to its asymmetric flux density distribution, was transported poleward more quickly on average than its trailing negative flux, contrary to the canonical pattern of bipole flux transport. This behavior caused the AR to have a smaller effect on the polar fields than expected and enabled the formation of the very long neutral line where the filament formed.
Solar magnetic activity cycles, coronal potential field models and eruption rates
Petrie, G J D
2013-01-01
We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the NSO's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun (SOLIS) vector spectro-magnetograph (VSM), the spectro-magnetograph and the 512-channel magnetograph instruments, and from the U. Stanford's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003-6 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the ...
Retroviral Vector Biosafety: Lessons from Sheep
Directory of Open Access Journals (Sweden)
Van den Broeke Anne
2003-01-01
Full Text Available The safety of retroviral-based systems and the possible transmission of replication-competent virus to patients is a major concern associated with using retroviral vectors for gene therapy. While much effort has been put into the design of safe retroviral production methods and effective in vitro monitoring assays, there is little data evaluating the risks resulting from retroviral vector instability at post-transduction stages especially following in vivo gene delivery. Here, we briefly describe and discuss our observations in an in vivo experimental model based on the inoculation of retroviral vector-transduced tumor cells in sheep. Our data indicates that the in vivo generation of mosaic viruses is a dynamic process and that virus variants, generated by retroviral vector-mediated recombination, may be stored and persist in infected individuals prior to selection at the level of replication. Recombination may not only restore essential viral functions or provide selective advantages in a changing environment but also reestablish or enhance the pathogenic potential of the particular virus undergoing recombination. These observations in sheep break new ground in our understanding of how retroviral vectors may have an impact on the course of a preestablished disease or reactivate dormant or endogenous viruses. The in vivo aspects of vector stability raise important biosafety issues for the future development of safe retroviral vector-based gene therapy.
The Representation of a Broadband Vector Field
Institute of Scientific and Technical Information of China (English)
Qunyan Ren; Jean Pierre Hermand; Shengchun Piao
2011-01-01
Compared to a scalar pressure sensor,a vector sensor can provide a higher signal-to-noise ratio (SNR)signal and more detailed information on the sound field.Study on vector sensors and their applications have become a hot topic.Research on the representation of a vector field is highly relevant for extending the scope of vector sensor technology.This paper discusses the range-frequency distribution of the vector field due to a broadband acoustic source moving in a shallow-water waveguide as the self noise of a surface ship,and the vector extension of the waveguide impulse response measured over a limited frequency range using an active source of known waveform.From theory analysis and numerical simulation,the range-frequency representation of a vector field exhibits an interference structure qualitatively similar to that of the corresponding pressure field but,being quantitatively different,provides additional information on the waveguide,especially through the vertical component.For the range-frequency representation,physical quantities that can better exhibit the interference characteristics of the waveguide are the products of pressure and particle velocity and of the pressure and pressure gradient.An image processing method to effectively detect and isolate the individual striations from an interference structure was reviewed briefly.The representation of the vector impulse response was discussed according to two different measurement systems,also known as particle velocity and pressure gradient.The vector impulse response representation can not only provide additional information from pressure only but even more than that of the range-frequency representation.
Efficient than a Nonlentiviral Vector
Directory of Open Access Journals (Sweden)
Tao Yang
2010-01-01
Full Text Available Background. Lentiviral constructs reportedly can integrate into the genome of non-dividing, terminally differentiated cells and dividing cells, for long-term gene expression. This investigation tested whether a third generation lentiviral-mediated small interfering RNA (siRNA delivered into renal epithelial and fibroblast cells against type II transforming growth factor-beta receptor (siRNA-TBRII could better attenuate renal fibrogenesis in comparison with a non-lentiviral construct. Methods. HIV-derived lentiviral and non-lentiviral constructs were used to transfect cells with siRNA-TBRII or siRNA-EGFP control. Human embryonic kidney (HEK-293T, renal epithelial cells (NRK-52E and renal fibroblasts (NRK-49F were transfected and gene silencing quantified (fluorescence microscopy, Western blotting, fluorescence-activated cell sorting. Renal fibrogenesis was assessed using extracellular matrix protein synthesis (fibronectin and collagen-III; Western immunoblot, and α-smooth muscle actin (α-SMA was analysed as a marker of fibroblast activation and epithelial-to-mesenchymal transdifferentiation (EMT. Results. Lentiviral-mediated siRNA-TBRII significantly suppressed TBRII expression in all cell lines, and also significantly suppressed renal fibrogenesis. In comparison with the non-lentiviral construct, lentiviral-mediated siRNA-TBRII produced stronger and more persistent inhibition of collagen-III in NRK-49F cells, fibronectin in all renal cell lines, and α-SMA in renal epithelial cells. Conclusions. Lentiviral vector systems against TBRII can be delivered into renal cells to efficiently limit renal fibrogenesis by sequence-specific gene silencing.
New Anomaly of the Axial-Vector Current
Institute of Scientific and Technical Information of China (English)
HE Han-Xin
2001-01-01
By computing the axial-vector current operator equation, we find the anomalous axial-vector curl equation besides the well-known anomalous axial-vector divergence equation (the Adler-Bell-Jackiw anomaly) and discuss its implication.``
600-GHz Electronically Tunable Vector Measurement System
Dengler, Robert; Maiwald, Frank; Siegel, Peter
2007-01-01
A compact, high-dynamic-range, electronically tunable vector measurement system that operates in the frequency range from approximately 560 to approximately 635 GHz has been developed as a prototype of vector measurement systems that would be suitable for use in nearly-real-time active submillimeter-wave imaging. As used here, 'vector measurement system" signifies an instrumentation system that applies a radio-frequency (RF) excitation to an object of interest and measures the resulting amplitude and phase response, relative to either the applied excitatory signal or another reference signal related in a known way to applied excitatory signal.
Robust Pseudo-Hierarchical Support Vector Clustering
DEFF Research Database (Denmark)
Hansen, Michael Sass; Sjöstrand, Karl; Olafsdóttir, Hildur
2007-01-01
Support vector clustering (SVC) has proven an efficient algorithm for clustering of noisy and high-dimensional data sets, with applications within many fields of research. An inherent problem, however, has been setting the parameters of the SVC algorithm. Using the recent emergence of a method...... for calculating the entire regularization path of the support vector domain description, we propose a fast method for robust pseudo-hierarchical support vector clustering (HSVC). The method is demonstrated to work well on generated data, as well as for detecting ischemic segments from multidimensional myocardial...
Nonlinear singular vectors and nonlinear singular values
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A novel concept of nonlinear singular vector and nonlinear singular value is introduced, which is a natural generalization of the classical linear singular vector and linear singular value to the nonlinear category. The optimization problem related to the determination of nonlinear singular vectors and singular values is formulated. The general idea of this approach is demonstrated by a simple two-dimensional quasigeostrophic model in the atmospheric and oceanic sciences. The advantage and its applications of the new method to the predictability, ensemble forecast and finite-time nonlinear instability are discussed. This paper makes a necessary preparation for further theoretical and numerical investigations.
A NEW HYPERSPHERE SUPPORT VECTOR MACHINE ALGORITHM
Institute of Scientific and Technical Information of China (English)
Zhang Xinfeng; Shen Lansun
2006-01-01
The hypersphere support vector machine is a new algorithm in pattern recognition. By studying three kinds ofhypersphere support vector machines, it is found that their solutions are identical and the margin between two classes of samples is zero or is not unique. In this letter, a new kind ofhypersphere support vector machine is proposed. By introducing a parameter n(n＞l), a unique solution of the margin can be obtained.Theoretical analysis and experimental results show that the proposed algorithm can achieve better generalization performance.
Kaur, Navneet; Hasegawa, Daniel K; Ling, Kai-Shu; Wintermantel, William M
2016-10-01
The relationships between plant viruses and their vectors have evolved over the millennia, and yet, studies on viruses began virus and vector interactions even more recently. The advent of next generation sequencing, including rapid genome and transcriptome analysis, methods for evaluation of small RNAs, and the related disciplines of proteomics and metabolomics offer a significant shift in the ability to elucidate molecular mechanisms involved in virus infection and transmission by insect vectors. Genomic technologies offer an unprecedented opportunity to examine the response of insect vectors to the presence of ingested viruses through gene expression changes and altered biochemical pathways. This review focuses on the interactions between viruses and their whitefly or thrips vectors and on potential applications of genomics-driven control of the insect vectors. Recent studies have evaluated gene expression in vectors during feeding on plants infected with begomoviruses, criniviruses, and tospoviruses, which exhibit very different types of virus-vector interactions. These studies demonstrate the advantages of genomics and the potential complementary studies that rapidly advance our understanding of the biology of virus transmission by insect vectors and offer additional opportunities to design novel genetic strategies to manage insect vectors and the viruses they transmit.
Ledesma, Nicholas; Harrington, Laura
2011-11-01
Dog heartworm (Dirofilaria immitis) is dependent on mosquito vectors for its maintenance and transmission among vertebrate hosts. Consequently, D. immitis abundance and distribution are closely linked with mosquito vector biology and ecology. Information on the important dog heartworm vectors in the United States is limited and no comprehensive surveillance of dog heartworm in US mosquitoes has been undertaken to date. Here, we review information gleaned from a number of field surveys documenting heartworm presence in wild mosquito populations as well as laboratory assessments of mosquito vector capacity. Various biological and ecological factors likely contribute to the relative importance of different vector species. We describe some of these factors, rank the leading criteria for efficient vectors, and present the most likely vector species found across the United States. Considering the recent emergence of drug resistance among D. immitis strains, practical knowledge of heartworm vector biology and control should be incorporated into heartworm disease management programs. We conclude by proposing that heartworm control would benefit by targeting mosquito vectors, and we suggest ways in which veterinarians can incorporate the recognition of vector importance into heartworm prevention recommendations imparted to clients. Copyright © 2011 Elsevier Inc. All rights reserved.
Viruses vector control proposal: genus Aedes emphasis
Directory of Open Access Journals (Sweden)
Nelson Nogueira Reis
Full Text Available Abstract The dengue fever is a major public health problem in the world. In Brazil, in 2015, there were 1,534,932 cases, being 20,320 cases of severe form, and 811 deaths related to this disease. The distribution of Aedes aegypti, the vector, is extensive. Recently, Zika and Chikungunya viruses had arisen, sharing the same vector as dengue and became a huge public health issue. Without specific treatment, it is urgently required as an effective vector control. This article is focused on reviewing vector control strategies, their effectiveness, viability and economical impact. Among all, the Sterile Insect Technique is highlighted as the best option to be adopted in Brazil, once it is largely effectively used in the USA and Mexico for plagues related to agribusiness.
Weaving knotted vector fields with tunable helicity
Kedia, Hridesh; Dennis, Mark R; Irvine, William T M
2016-01-01
We present a general construction of divergence-free knotted vector fields from complex scalar fields, whose closed field lines encode many kinds of knots and links, including torus knots, their cables, the figure-8 knot and its generalizations. As finite-energy physical fields they represent initial states for fields such as the magnetic field in a plasma, or the vorticity field in a fluid. We give a systematic procedure for calculating the vector potential, starting from complex scalar functions with knotted zero filaments, thus enabling an explicit computation of the helicity of these knotted fields. The construction can be used to generate isolated knotted flux tubes, filled by knots encoded in the lines of the vector field. Lastly we give examples of manifestly knotted vector fields with vanishing helicity. Our results provide building blocks for analytical models and simulations alike.
Low Power, Self Calibrated Vector Magnetometer Project
National Aeronautics and Space Administration — This Phase I SBIR project investigates a novel approach to vector magnetometry based on high precision measurements of the total magnetic field. The calibration is...
Integrated epidemiology for vector-borne zoonoses.
Wardrop, Nicola A
2016-02-01
The development and application of interventions for the control of vector-borne zoonoses requires broad understanding of epidemiological linkages between vector, animal infection and human infection. However, there are significant gaps in our understanding of these linkages and a lack of appropriate data poses a considerable barrier to addressing this issue. A move towards strengthened surveillance of vectors and disease in both animal and human hosts, in combination with linked human-animal surveys, could form the backbone for epidemiological integration, enabling explicit assessment of the animal-human (and vector) interface, and subsequent implications for spill-over to human populations. Currently available data on the spatial distribution of human African trypanosomiasis allow an illustrative example.
Sensorless vector and direct torque control
Vas, Peter
1998-01-01
This is the first comprehensive book on sensorless high performance a.c. drives. It is essential reading for anyone interested in acquiring a solid background on sensorless torque-controlled drives. It presents a detailed and unified treatment of sensorless vector-controlled and direct-torque controlled drive systems. It also discusses the applications of artificial intelligence to drives. Where possible, space vector theory is used and emphasis is laid on detailed mathematical and physical analysis. Sensorless drive schemes for different types of permanent magnet synchronous motors, synchronous reluctance motors, and induction motors are also presented. These include more than twenty vector drives e.g. five types of MRAS-based vector drives, and eleven types of direct-torque-controlled (DTC) drives, e.g. the ABB DTC drive. However, torque-controlled switched reluctance motor drives are also discussed due to their emerging importance. The book also covers various drive applications using artificial intellige...
Generalized Stokes vector for three photon process
Shaji, Chitra; Satyanarayana, SVM; Sharan, Alok
2015-01-01
Stokes Muller formalism is important to understand the optical properties of materials by measuring the change in the polarization state of light upon scattering. The formalism can be extended to nonlinear scattering processes involving two and three photon processes. In this work, we derive a triple Stokes vector analytically using operator approach used in quantum theory of light. A three photon polarization state can be described by Stokes vector that has sixteen components involving cubes of intensities. The response of a material for the scattering of light in a three photon process is described by 4 x 16 Muller matrix. Polarization in Polarization out (PIPO) experiments can be carried out to determine the elements of Muller matrix. For that we identify 16 independent points in Poincare sphere and construct triple Stokes vector for each point. Four measurements to find the linear Stokes vector of the scattered light for incident light in each of the sixteen three photon states determine the Muller matrix...
Gamow Vectors Explain the Shock "Batman" Profile
Braidotti, Maria Chiara; Conti, Claudio
2016-01-01
The description of shock waves beyond the shock point is a challenge in nonlinear physics. Finding solutions to the global dynamics of dispersive shock waves is not always possible due to the lack of integrability. Here we propose a new method based on the eigenstates (Gamow vectors) of a reversed harmonic oscillator in a rigged Hilbert space. These vectors allow analytical formulation for the development of undular bores of shock waves in a nonlinear nonlocal medium. Experiments by a photothermal induced nonlinearity confirm theoretical predictions: as the undulation period as a function of power and the characteristic quantized decays of Gamow vectors. Our results demonstrate that Gamow vector are a novel and effective paradigm for describing extreme nonlinear phenomena.
Triangle Lattice Green Functions for Vector Fields
Moritz, Brian; Schwalm, William
2000-03-01
The triangle lattice is convenient for modeling fields and fluid flows in two dimensions. Discrete vector field equations are defined through the analogy between differential forms and simplicial homology theory. The basic vector difference operators on the lattice correspond to the graph adjacency matricies of the triangle, honeycomb, and Kagomé lattices. The scalar Green functions for nearest neighbor interactions on the triangle lattice are known in closed form in terms of the complete elliptic integrals. Green functions for vector field operators are obtained explicitly in terms of the known scalar Green functions. The scalar Green functions for the Kagomé lattice are thus written in terms of the Green functions for the triangle lattice and ultimately in closed form. Thus, Green functions for a wide range of vector difference models are reduced to closed form in terms of the complete elliptic integrals.
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Ivan Kausz
2005-05-01
Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich’s and Vistoli’s twisted bundles and Gieseker vector bundles.
Poynting Vector Flow in a Circular Circuit
Davis, Basil S; 10.1119/1.3630927
2012-01-01
A circuit is considered in the shape of a ring, with a battery of negligible size and a wire of uniform resistance. A linear charge distribution along the wire maintains an electrostatic field and a steady current, which produces a constant magnetic field. Earlier studies of the Poynting vector and the rate of flow of energy considered only idealized geometries in which the Poynting vector was confined to the space within the circuit. But in more realistic cases the Poynting vector is nonzero outside as well as inside the circuit. An expression is obtained for the Poynting vector in terms of products of integrals, which are evaluated numerically to show the energy flow. Limiting expressions are obtained analytically. It is shown that the total power generated by the battery equals the energy flowing into the wire per unit time.
Gamow vectors explain the shock profile.
Braidotti, Maria Chiara; Gentilini, Silvia; Conti, Claudio
2016-09-19
The description of shock waves beyond the shock point is a challenge in nonlinear physics and optics. Finding solutions to the global dynamics of dispersive shock waves is not always possible due to the lack of integrability. Here we propose a new method based on the eigenstates (Gamow vectors) of a reversed harmonic oscillator in a rigged Hilbert space. These vectors allow analytical formulation for the development of undular bores of shock waves in a nonlinear nonlocal medium. Experiments by a photothermal induced nonlinearity confirm theoretical predictions: the undulation period as a function of power and the characteristic quantized decays of Gamow vectors. Our results demonstrate that Gamow vectors are a novel and effective paradigm for describing extreme nonlinear phenomena.
Construction of expression vectors carrying mouse peroxisomal ...
African Journals Online (AJOL)
PRECIOUS
2009-11-16
cloned in pGEX6p2 prokaryotic expression vector ... network controls biogenesis and division (Pex11p, 23p, ... The coding region of PEP (PEP-cDNA) was inserted into the ..... Metabolic and molecular basis of peroxisomal.
VEST: Abstract Vector Calculus Simplification in Mathematica
Energy Technology Data Exchange (ETDEWEB)
J. Squire, J. Burby and H. Qin
2013-03-12
We present a new package, VEST (Vector Einstein Summation Tools), that performs abstract vector calculus computations in Mathematica. Through the use of index notation, VEST is able to reduce scalar and vector expressions of a very general type using a systematic canonicalization procedure. In addition, utilizing properties of the Levi-Civita symbol, the program can derive types of multi-term vector identities that are not recognized by canonicalization, subsequently applying these to simplify large expressions. In a companion paper [1], we employ VEST in the automation of the calculation of Lagrangians for the single particle guiding center system in plasma physics, a computation which illustrates its ability to handle very large expressions. VEST has been designed to be simple and intuitive to use, both for basic checking of work and more involved computations. __________________________________________________
Vector optimization theory, applications, and extensions
Jahn, Johannes
2011-01-01
This new edition of a key monograph has fresh sections on the work of Edgeworth and Pareto in its presentation in a general setting of the fundamentals and important results of vector optimization. It examines background material, applications and theories.
Insects as vectors: systematics and biology.
Rodhain, F
2015-04-01
Among the many complex relationships between insects and microorganisms such as viruses, bacteria and parasites, some have resulted in the establishment of biological systems within which the insects act as a biological vector for infectious agents. It is therefore advisable to understand the identity and biology of these vectors in depth, in order to define procedures for epidemiological surveillance and anti-vector control. The following are successively reviewed in this article: Anoplura (lice), Siphonaptera (fleas), Heteroptera (bugs: Cimicidae, Triatoma, Belostomatidae), Psychodidae (sandflies), Simuliidae (black flies), Ceratopogonidae (biting midges), Culicidae (mosquitoes), Tabanidae (horseflies) and Muscidae (tsetse flies, stable flies and pupipara). The authors provide a rapid overview of the morphology, systematics, development cycle and bio-ecology of each of these groups of vectors. Finally, their medical and veterinary importance is briefly reviewed.
Small automorphic representations and degenerate Whittaker vectors
Gustafsson, Henrik P A; Persson, Daniel
2014-01-01
We investigate Fourier coefficients of automorphic forms on split simply-laced Lie groups G. We show that for automorphic representations of small Gelfand-Kirillov dimension the Fourier coefficients are completely determined by certain degenerate Whittaker vectors on G. Although we expect our results to hold for arbitrary simply-laced groups, we give complete proofs only for G=SL(3) and G=SL(4). This is based on a method of Ginzburg that associates Fourier coefficients of automorphic forms with nilpotent orbits of G. Our results complement and extend recent results of Miller and Sahi. We also use our formalism to calculate various local (real and p-adic) spherical vectors of minimal representations of the exceptional groups E_6, E_7, E_8 using global (adelic) degenerate Whittaker vectors, correctly reproducing existing results for such spherical vectors obtained by very different methods.
Neural net approach to predictive vector quantization
Mohsenian, Nader; Nasrabadi, Nasser M.
1992-11-01
A new predictive vector quantization (PVQ) technique, capable of exploring the nonlinear dependencies in addition to the linear dependencies that exist between adjacent blocks of pixels, is introduced. Two different classes of neural nets form the components of the PVQ scheme. A multi-layer perceptron is embedded in the predictive component of the compression system. This neural network, using the non-linearity condition associated with its processing units, can perform as a non-linear vector predictor. The second component of the PVQ scheme vector quantizes (VQ) the residual vector that is formed by subtracting the output of the perceptron from the original wave-pattern. Kohonen Self-Organizing Feature Map (KSOFM) was utilized as a neural network clustering algorithm to design the codebook for the VQ technique. Coding results are presented for monochrome 'still' images.
Vector Potential Generation for Numerical Relativity Simulations
Silberman, Zachary; Faber, Joshua; Adams, Thomas; Etienne, Zachariah; Ruchlin, Ian
2017-01-01
Many different numerical codes are employed in studies of highly relativistic magnetized accretion flows around black holes. Based on the formalisms each uses, some codes evolve the magnetic field vector B, while others evolve the magnetic vector potential A, the two being related by the curl: B=curl(A). Here, we discuss how to generate vector potentials corresponding to specified magnetic fields on staggered grids, a surprisingly difficult task on finite cubic domains. The code we have developed solves this problem in two ways: a brute-force method, whose scaling is nearly linear in the number of grid cells, and a direct linear algebra approach. We discuss the success both algorithms have in generating smooth vector potential configurations and how both may be extended to more complicated cases involving multiple mesh-refinement levels. NSF ACI-1550436
CONTROL CHARTS FOR STATIONARY VECTOR ARMA PROCESSES
National Research Council Canada - National Science Library
Yadavalli, J; Claasen, S.J; Singh, N
2012-01-01
.... To the author's best knowledge, no concrete attempts have been made so far to construct the control charts for such situations, particularly when the data arise from vector autoregressive-moving average (VARMA) processes...
Students’ difficulties with vector calculus in electrodynamics
Directory of Open Access Journals (Sweden)
Laurens Bollen
2015-11-01
Full Text Available Understanding Maxwell’s equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven encounter with the divergence and curl of a vector field in mathematical and physical contexts. We have found that they are quite skilled at doing calculations, but struggle with interpreting graphical representations of vector fields and applying vector calculus to physical situations. We have found strong indications that traditional instruction is not sufficient for our students to fully understand the meaning and power of Maxwell’s equations in electrodynamics.
The light filament as vector solitary wave
Kovachev, Lubomir M
2015-01-01
We present an analytical approach to the theory of nonlinear propagation of femtosecond optical pulses with broad-band spectrum in gases. The vector character of the nonlinear third-order polarization is investigated in details, taking into account the carrier to envelope phase. The corresponding system of vector amplitude equations is written by using left-hand and right-hand circular components of the electrical field. We found that this system nonlinear equations admits $3D+1$ vector soliton solution with Lorentz shape. The solution presents relatively stable propagation and rotation with GHz frequency of the vector of the electrical field in plane, orthogonal to the direction of propagation. The evolution of the intensity profile demonstrate weak self-compression and week spherical wave in the first milliseconds of propagation.
Ontology for vector surveillance and management.
Lozano-Fuentes, Saul; Bandyopadhyay, Aritra; Cowell, Lindsay G; Goldfain, Albert; Eisen, Lars
2013-01-01
Ontologies, which are made up by standardized and defined controlled vocabulary terms and their interrelationships, are comprehensive and readily searchable repositories for knowledge in a given domain. The Open Biomedical Ontologies (OBO) Foundry was initiated in 2001 with the aims of becoming an "umbrella" for life-science ontologies and promoting the use of ontology development best practices. A software application (OBO-Edit; *.obo file format) was developed to facilitate ontology development and editing. The OBO Foundry now comprises over 100 ontologies and candidate ontologies, including the NCBI organismal classification ontology (NCBITaxon), the Mosquito Insecticide Resistance Ontology (MIRO), the Infectious Disease Ontology (IDO), the IDOMAL malaria ontology, and ontologies for mosquito gross anatomy and tick gross anatomy. We previously developed a disease data management system for dengue and malaria control programs, which incorporated a set of information trees built upon ontological principles, including a "term tree" to promote the use of standardized terms. In the course of doing so, we realized that there were substantial gaps in existing ontologies with regards to concepts, processes, and, especially, physical entities (e.g., vector species, pathogen species, and vector surveillance and management equipment) in the domain of surveillance and management of vectors and vector-borne pathogens. We therefore produced an ontology for vector surveillance and management, focusing on arthropod vectors and vector-borne pathogens with relevance to humans or domestic animals, and with special emphasis on content to support operational activities through inclusion in databases, data management systems, or decision support systems. The Vector Surveillance and Management Ontology (VSMO) includes >2,200 unique terms, of which the vast majority (>80%) were newly generated during the development of this ontology. One core feature of the VSMO is the linkage, through
Nonperturbative Aspects of Axial Vector Vertex
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang
2002-01-01
It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.
Dynamics of localized structures in vector waves
Hernández-García, E; Colet, P; San Miguel, M; Hernandez-Garcia, Emilio; Hoyuelos, Miguel; Colet, Pere; Miguel, Maxi San
1999-01-01
Dynamical properties of topological defects in a twodimensional complex vector field are considered. These objects naturally arise in the study of polarized transverse light waves. Dynamics is modeled by a Vector Complex Ginzburg-Landau Equation with parameter values appropriate for linearly polarized laser emission. Creation and annihilation processes, and selforganization of defects in lattice structures, are described. We find "glassy" configurations dominated by vectorial defects and a melting process associated to topological-charge unbinding.
Solving Parity Games on Integer Vectors
Abdulla, Parosh Aziz; Mayr, Richard; Sangnier, Arnaud; Sproston, Jeremy
2013-01-01
We consider parity games on infinite graphs where configurations are represented by control-states and integer vectors. This framework subsumes two classic game problems: parity games on vector addition systems with states (vass) and multidimensional energy parity games. We show that the multidimensional energy parity game problem is inter-reducible with a subclass of single-sided parity games on vass where just one player can modify the integer counters and the opponent can only change contr...
Vector database for vehicle road navigation
Kenda, Lian
2007-01-01
Vehicle navigation devices use vector cartographic view, which is designed as a vector database. Database creation begins by setting up a landscape model which includes all the graphical and descriptive data required for accurate vehicle navigation. This paper presents the creation of a database part called StreetConnect, which is used for road navigation. Data obtained using distinct specifications have been transformed into the format compatible with Garmin GPS devices. Data have been obtai...
Trichophoromyia auraensis is a putative vector
Directory of Open Access Journals (Sweden)
Carolina Bioni Garcia Teles
Full Text Available The sandfly Trichophoromyia auraensis has recently evolved as a proven vector of Leishmania (Viannia endemic to state of Acre in the north of Brazil. This note is intended to propose a correction in the report of the first occurrence of natural infection of Leishmania (Viannia in this species. We and the other scientific groups reinforced that Tr. auraensis is a possible vector involved in the transmission of American cutaneous leishmaniasis in Acre, Brazil.
Killing vector fields and harmonic superfield theories
Energy Technology Data Exchange (ETDEWEB)
Groeger, Josua, E-mail: groegerj@mathematik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Mathematik, Rudower Chaussee 25, 12489 Berlin (Germany)
2014-09-15
The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, also referred to as harmonic, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of this harmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.
Killing Vector Fields and Superharmonic Field Theories
Groeger, Josua
2013-01-01
The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, referred to as superharmonic action, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of the superharmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.
Visualization of Vector Field by Virtual Reality
Kageyama, A.; Tamura, Y.; Sato, T.
A visualization software program is developed in order to analyze three dimensional vector fields by means of today's advanced virtual reality technology. This program enables simulation researchers to interactively visualize stream lines, tracer particle motions, isosurfaces, etc.~with stereo view. The program accepts any kind of vector fields on structured mesh as an input data. A virtual reality hardware system, on which the program operates, and details of the program are described.
New approach to training support vector machine
Institute of Scientific and Technical Information of China (English)
Tang Faming; Chen Mianyun; Wang Zhongdong
2006-01-01
Support vector machine has become an increasingly popular tool for machine learning tasks involving classification, regression or novelty detection. Training a support vector machine requires the solution of a very large quadratic programming problem. Traditional optimization methods cannot be directly applied due to memory restrictions. Up to now, several approaches exist for circumventing the above shortcomings and work well. Another learning algorithm, particle swarm optimization, for training SVM is introduted. The method is tested on UCI datasets.
Using multivalent adenoviral vectors for HIV vaccination.
Directory of Open Access Journals (Sweden)
Linlin Gu
Full Text Available Adenoviral vectors have been used for a variety of vaccine applications including cancer and infectious diseases. Traditionally, Ad-based vaccines are designed to express antigens through transgene expression of a given antigen. For effective vaccine development it is often necessary to express or present multiple antigens to the immune system to elicit an optimal vaccine as observed preclinically with mosaic/polyvalent HIV vaccines or malaria vaccines. Due to the wide flexibility of Ad vectors they are an ideal platform for expressing large amounts of antigen and/or polyvalent mosaic antigens. Ad vectors that display antigens on their capsid surface can elicit a robust humoral immune response, the "antigen capsid-incorporation" strategy. The adenoviral hexon protein has been utilized to display peptides in the majority of vaccine strategies involving capsid incorporation. Based on our abilities to manipulate hexon HVR2 and HVR5, we sought to manipulate HVR1 in the context of HIV antigen display for the first time ever. More importantly, peptide incorporation within HVR1 was utilized in combination with other HVRs, thus creating multivalent vectors. To date this is the first report where dual antigens are displayed within one Ad hexon particle. These vectors utilize HVR1 as an incorporation site for a seven amino acid region of the HIV glycoprotein 41, in combination with six Histidine incorporation within HVR2 or HVR5. Our study illustrates that these multivalent antigen vectors are viable and can present HIV antigen as well as His6 within one Ad virion particle. Furthermore, mouse immunizations with these vectors demonstrate that these vectors can elicit a HIV and His6 epitope-specific humoral immune response.
Null vectors of the $WBC_2$ algebra
Bajnok, Z
1994-01-01
Using the fusion principle of Bauer et al. we give explicit expressions for some null vectors in the highest weight representations of the \\bc algebra in two different forms. These null vectors are the generalization of the Virasoro ones described by Benoit and Saint-Aubin and analogues of the $W_3$ ones constructed by Bowcock and Watts. We find connection between quantum Toda models and the fusion method.
Improvised microinjection technique for mosquito vectors
Sampath, Kumar S.; H.P.Puttaraju
2012-01-01
Background & objectives: Bio-manipulation technique is of primary importance during the development of transgenic mosquitoes. The study describes the variable factors that influence the viability of medically important mosquito vectors during microinjection. Methods: Three mosquito vectors belonging to the genus Aedes, Anopheles and Culex were microinjected at different developmental stages of their life cycle viz., egg, larvae, pupae and adult. Results: The improvisations revealed an increas...
Byzantine Vector Consensus in Complete Graphs
2013-02-11
communication network is a complete graph. All the communication channels are reliable and FIFO (first-in-first-out). The problem of Byzantine vector...the communication network is a complete graph. All the communication channels are reliable and FIFO ( rst-in- rst-out). The problem of Byzantine...other directly on reliable FIFO (first-in first-out) channels. Thus, the communication network is a complete graph. The input vector at each process
Vector field processing on triangle meshes
De Goes, Fernando; Desbrun, Mathieu; Tong, Yiying
2015-01-01
While scalar fields on surfaces have been staples of geometry processing, the use of tangent vector fields has steadily grown in geometry processing over the last two decades: they are crucial to encoding directions and sizing on surfaces as commonly required in tasks such as texture synthesis, non-photorealistic rendering, digital grooming, and meshing. There are, however, a variety of discrete representations of tangent vector fields on triangle meshes, and each approach offers different tr...
Students' difficulties with vector calculus in electrodynamics
2015-01-01
Understanding Maxwell's equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven encounter with the divergence and curl of a vector field in mathematical and physical contexts. We have found that they are quite skilled at doing ca...
Retroviral Vector Biosafety: Lessons from Sheep
Van den Broeke Anne; Burny Arsène
2003-01-01
The safety of retroviral-based systems and the possible transmission of replication-competent virus to patients is a major concern associated with using retroviral vectors for gene therapy. While much effort has been put into the design of safe retroviral production methods and effective in vitro monitoring assays, there is little data evaluating the risks resulting from retroviral vector instability at post-transduction stages especially following in vivo gene delivery. Here, we briefly desc...
Effects of Climate and Climate Change on Vectors and Vector-Borne Diseases: Ticks Are Different.
Ogden, Nick H; Lindsay, L Robbin
2016-08-01
There has been considerable debate as to whether global risk from vector-borne diseases will be impacted by climate change. This has focussed on important mosquito-borne diseases that are transmitted by the vectors from infected to uninfected humans. However, this debate has mostly ignored the biological diversity of vectors and vector-borne diseases. Here, we review how climate and climate change may impact those most divergent of arthropod disease vector groups: multivoltine insects and hard-bodied (ixodid) ticks. We contrast features of the life cycles and behaviour of these arthropods, and how weather, climate, and climate change may have very different impacts on the spatiotemporal occurrence and abundance of vectors, and the pathogens they transmit.
Lee, Dukhyung; Kim, Dai-Sik
2016-01-07
We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet's principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet's principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.
Vector analyses of linearly and circularly polarized Bessel beams using Hertz vector potentials.
Wang, Yanxun; Dou, Wenbin; Meng, Hongfu
2014-04-07
Using the transverse Hertz vector potentials, vector analyses of linearly and circularly polarized Bessel beams of arbitrary orders are presented in this paper. Expressions for the electric and magnetic fields of vector Bessel beams in free space that are rigorous solutions to the vector Helmholtz equation are derived. Their respective time averaged energy density and Poynting vector are also obtained, in order to exhibit their non-diffracting properties. Polarization patterns and magnitude profiles with different parameters are displayed. Particular emphasis is placed on the cases where the ratio of wave number over its transverse component k/kt approximately equals to one and largely exceeds it, which corresponding to the nonparaxial and paraxial condition, respectively. These results allow us to recognize that the vector Bessel beams exhibit new and important features, compared with the scalar fields.
An Algorithm for Interpolating Ship Motion Vectors
Directory of Open Access Journals (Sweden)
Qinyou Hu
2014-03-01
Full Text Available Interpolation of ship motion vectors is able to be used for estimating the lost ship AIS dynamic information, which is important for replaying marine accidents and for analysing marine traffic data. The previous methods can only interpolate ship's position, while not including ship's course and speed. In this paper, vector function is used to express the relationship between the ship's time and space coordinates, and the tangent of the vector function and its change rate are able to express physical characteristics of ship's course, speed and acceleration. The given AIS dynamic information can be applied to calculate the parameters of ship's vector function and then the interpolation model for ship motion vectors is developed to estimate the lost ship dynamic information at any given moment. Experiment results show that the ship motion vector function is able to depict the characteristics of ship motions accurately and the model can estimate not only the ship's position but also ship's course and speed at any given moment with limited differences.
Black holes in vector-tensor theories
Heisenberg, Lavinia; Kase, Ryotaro; Minamitsuji, Masato; Tsujikawa, Shinji
2017-08-01
We study static and spherically symmetric black hole (BH) solutions in second-order generalized Proca theories with nonminimal vector field derivative couplings to the Ricci scalar, the Einstein tensor, and the double dual Riemann tensor. We find concrete Lagrangians which give rise to exact BH solutions by imposing two conditions of the two identical metric components and the constant norm of the vector field. These exact solutions are described by either Reissner-Nordström (RN), stealth Schwarzschild, or extremal RN solutions with a non-trivial longitudinal mode of the vector field. We then numerically construct BH solutions without imposing these conditions. For cubic and quartic Lagrangians with power-law couplings which encompass vector Galileons as the specific cases, we show the existence of BH solutions with the difference between two non-trivial metric components. The quintic-order power-law couplings do not give rise to non-trivial BH solutions regular throughout the horizon exterior. The sixth-order and intrinsic vector-mode couplings can lead to BH solutions with a secondary hair. For all the solutions, the vector field is regular at least at the future or past horizon. The deviation from General Relativity induced by the Proca hair can be potentially tested by future measurements of gravitational waves in the nonlinear regime of gravity.
Feature Vector Construction Method for IRIS Recognition
Odinokikh, G.; Fartukov, A.; Korobkin, M.; Yoo, J.
2017-05-01
One of the basic stages of iris recognition pipeline is iris feature vector construction procedure. The procedure represents the extraction of iris texture information relevant to its subsequent comparison. Thorough investigation of feature vectors obtained from iris showed that not all the vector elements are equally relevant. There are two characteristics which determine the vector element utility: fragility and discriminability. Conventional iris feature extraction methods consider the concept of fragility as the feature vector instability without respect to the nature of such instability appearance. This work separates sources of the instability into natural and encodinginduced which helps deeply investigate each source of instability independently. According to the separation concept, a novel approach of iris feature vector construction is proposed. The approach consists of two steps: iris feature extraction using Gabor filtering with optimal parameters and quantization with separated preliminary optimized fragility thresholds. The proposed method has been tested on two different datasets of iris images captured under changing environmental conditions. The testing results show that the proposed method surpasses all the methods considered as a prior art by recognition accuracy on both datasets.
An Unbroken Axial Vector Current Conservation Law
Sharafiddinov, Rasulkhozha S
2015-01-01
The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space i...
Trobridge, Grant; Russell, David W
2004-03-01
Retroviral vectors based on foamy viruses (FV) are efficient gene delivery vehicles for therapeutic and research applications. While previous studies have shown that FV vectors transduce quiescent cell cultures more efficiently than oncoviral vectors, their specific cell cycle requirements have not been determined. Here we compare the transduction frequencies of FV vectors with those of onco- and lentiviral vectors in nondividing and dividing normal human fibroblasts by several methods. FV vectors transduced serum-deprived fibroblast cultures more efficiently than oncoretroviral vectors and at rates comparable to those of lentiviral vectors. However, in these cultures FV vectors only transduced a subpopulation of proliferating cells, as determined by bromodeoxyuridine staining for DNA synthesis. In contrast to lentiviral vectors, FV vectors were unable to transduce human fibroblasts arrested by aphidicolin (G(1)/S phase) or gamma-irradiation (G(2) phase), and a partial cell cycle that included mitosis but not DNA synthesis was required. We could not determine if mitosis facilitated nuclear entry of FV vectors, since cell-free vector preparations contained long terminal repeat circles, precluding their use as nuclear markers. In contrast to oncoviral vectors, both FV and lentiviral vectors efficiently transduced G(0) fibroblasts that were later stimulated to divide. In the case of FV vectors, this was due to the persistence of a stable transduction intermediate in quiescent cells. Our findings support the use of FV vectors as a safe and effective alternative to lentiviral vectors for ex vivo transduction of stem cells that are quiescent during culture but divide following transplantation.
A COMPREHENSIVE ANALYSIS OF SPACE VECTOR PWM TECHNIQUE BASED ON PLACEMENT OF ZERO-SPACE VECTOR
Directory of Open Access Journals (Sweden)
G.SAMBASIVA RAO,
2011-04-01
Full Text Available In this paper, the effect of placement of zero-space vector for the implementation of space vector based Pulse Width Modulation techniques for 3-phase Voltage Source Inverter is presented. Several pulse width modulation (PWM control strategies have been proposed for 3-phase voltage source inverter (VSI in the past. It is known that space vector modulation (SVM offers a degree of freedom in its implementation with regard to the placement of the zero-space vector. Apart from constructing a consistent theoretical framework, simulation results with conventional continuous SVM and various discontinuous SVM techniques are presented and all the cases are compared in this paper.
Henan Zhao; Bryant, Garnett W; Griffin, Wesley; Terrill, Judith E; Jian Chen
2017-06-01
We designed and evaluated SplitVectors, a new vector field display approach to help scientists perform new discrimination tasks on large-magnitude-range scientific data shown in three-dimensional (3D) visualization environments. SplitVectors uses scientific notation to display vector magnitude, thus improving legibility. We present an empirical study comparing the SplitVectors approach with three other approaches - direct linear representation, logarithmic, and text display commonly used in scientific visualizations. Twenty participants performed three domain analysis tasks: reading numerical values (a discrimination task), finding the ratio between values (a discrimination task), and finding the larger of two vectors (a pattern detection task). Participants used both mono and stereo conditions. Our results suggest the following: (1) SplitVectors improve accuracy by about 10 times compared to linear mapping and by four times to logarithmic in discrimination tasks; (2) SplitVectors have no significant differences from the textual display approach, but reduce cluttering in the scene; (3) SplitVectors and textual display are less sensitive to data scale than linear and logarithmic approaches; (4) using logarithmic can be problematic as participants' confidence was as high as directly reading from the textual display, but their accuracy was poor; and (5) Stereoscopy improved performance, especially in more challenging discrimination tasks.
Viral Vectors for in Vivo Gene Transfer
Thévenot, E.; Dufour, N.; Déglon, N.
The transfer of DNA into the nucleus of a eukaryotic cell (gene transfer) is a central theme of modern biology. The transfer is said to be somatic when it refers to non-germline organs of a developed individual, and germline when it concerns gametes or the fertilised egg of an animal, with the aim of transmitting the relevant genetic modification to its descendents [1]. The efficient introduction of genetic material into a somatic or germline cell and the control of its expression over time have led to major advances in understanding how genes work in vivo, i.e., in living organisms (functional genomics), but also to the development of innovative therapeutic methods (gene therapy). The efficiency of gene transfer is conditioned by the vehicle used, called the vector. Desirable features for a vector are as follows: Easy to produce high titer stocks of the vector in a reproducible way. Absence of toxicity related to transduction (transfer of genetic material into the target cell, and its expression there) and no immune reaction of the organism against the vector and/or therapeutic protein. Stability in the expression of the relevant gene over time, and the possibility of regulation, e.g., to control expression of the therapeutic protein on the physiological level, or to end expression at the end of treatment. Transduction of quiescent cells should be as efficient as transduction of dividing cells. Vectors currently used fall into two categories: non-viral and viral vectors. In non-viral vectors, the DNA is complexed with polymers, lipids, or cationic detergents (described in Chap. 3). These vectors have a low risk of toxicity and immune reaction. However, they are less efficient in vivo than viral vectors when it comes to the number of cells transduced and long-term transgene expression. (Naked DNA transfer or electroporation is rather inefficient in the organism. This type of gene transfer will not be discussed here, and the interested reader is referred to the
Inverse Operation of Four-dimensional Vector Matrix
Directory of Open Access Journals (Sweden)
H J Bao
2011-08-01
Full Text Available This is a new series of study to define and prove multidimensional vector matrix mathematics, which includes four-dimensional vector matrix determinant, four-dimensional vector matrix inverse and related properties. There are innovative concepts of multi-dimensional vector matrix mathematics created by authors with numerous applications in engineering, math, video conferencing, 3D TV, and other fields.
40 CFR 503.33 - Vector attraction reduction.
2010-07-01
... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Vector attraction reduction. 503.33... STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE Pathogens and Vector Attraction Reduction § 503.33 Vector attraction reduction. (a)(1) One of the vector attraction reduction requirements in § 503.33 (b)(1)...
Chern-Simons Couplings and Inequivalent Vector-Tensor Multiplets
Claus, P.; Wit, B. de; Faux, M.; Termonia, P.
1996-01-01
The off-shell vector-tensor multiplet is considered in an arbitrary background of N=2 vector supermultiplets. We establish the existence of two inequivalent versions, characterized by different Chern-Simons couplings. In one version the vector field of the vector-tensor multiplet is contained
New Approach to Fractal Approximation of Vector-Functions
Directory of Open Access Journals (Sweden)
Konstantin Igudesman
2015-01-01
Full Text Available This paper introduces new approach to approximation of continuous vector-functions and vector sequences by fractal interpolation vector-functions which are multidimensional generalization of fractal interpolation functions. Best values of fractal interpolation vector-functions parameters are found. We give schemes of approximation of some sets of data and consider examples of approximation of smooth curves with different conditions.
Investigation of Optimal Integrated Circuit Raster Image Vectorization Method
Directory of Open Access Journals (Sweden)
Leonas Jasevičius
2011-03-01
Full Text Available Visual analysis of integrated circuit layer requires raster image vectorization stage to extract layer topology data to CAD tools. In this paper vectorization problems of raster IC layer images are presented. Various line extraction from raster images algorithms and their properties are discussed. Optimal raster image vectorization method was developed which allows utilization of common vectorization algorithms to achieve the best possible extracted vector data match with perfect manual vectorization results. To develop the optimal method, vectorized data quality dependence on initial raster image skeleton filter selection was assessed.Article in Lithuanian
LHC Signatures of Vector-Like Quarks
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Yasuhiro Okada
2013-01-01
Full Text Available This work provides an overview on the current status of phenomenology and searches for heavy vector-like quarks, which are predicted in many models of new physics beyond the Standard Model. Searches at Tevatron and at the LHC, here listed and shortly described, have not found any evidence for new heavy fermionic states (either chiral or vector-like and have therefore posed strong bounds on their masses: depending on specific assumptions on the interactions and on the observed final state, vector-like quarks with masses up to roughly 400–600 GeV have been excluded by all experiments. In order to be as simple and model independent as possible, the chosen framework for the phenomenological analysis is an effective model with the addition of a vector-like quark representation (singlet, doublet, or triplet under SU(2L which couples through Yukawa interactions with all SM families. The relevance of different observables for the determination of bounds on mixing parameters is then discussed and a complete overview of possible two body final states for every vector-like quark is provided, including their subsequent decay into SM particles. A list and short description of phenomenological analyses present in the literature are also provided for reference purposes.
Affine conformal vectors in space-time
Coley, A. A.; Tupper, B. O. J.
1992-05-01
All space-times admitting a proper affine conformal vector (ACV) are found. By using a theorem of Hall and da Costa, it is shown that such space-times either (i) admit a covariantly constant vector (timelike, spacelike, or null) and the ACV is the sum of a proper affine vector and a conformal Killing vector or (ii) the space-time is 2+2 decomposable, in which case it is shown that no ACV can exist (unless the space-time decomposes further). Furthermore, it is proved that all space-times admitting an ACV and a null covariantly constant vector (which are necessarily generalized pp-wave space-times) must have Ricci tensor of Segré type {2,(1,1)}. It follows that, among space-times admitting proper ACV, the Einstein static universe is the only perfect fluid space-time, there are no non-null Einstein-Maxwell space-times, and only the pp-wave space-times are representative of null Einstein-Maxwell solutions. Otherwise, the space-times can represent anisotropic fluids and viscous heat-conducting fluids, but only with restricted equations of state in each case.
Perceptual vector quantization for video coding
Valin, Jean-Marc; Terriberry, Timothy B.
2015-03-01
This paper applies energy conservation principles to the Daala video codec using gain-shape vector quantization to encode a vector of AC coefficients as a length (gain) and direction (shape). The technique originates from the CELT mode of the Opus audio codec, where it is used to conserve the spectral envelope of an audio signal. Conserving energy in video has the potential to preserve textures rather than low-passing them. Explicitly quantizing a gain allows a simple contrast masking model with no signaling cost. Vector quantizing the shape keeps the number of degrees of freedom the same as scalar quantization, avoiding redundancy in the representation. We demonstrate how to predict the vector by transforming the space it is encoded in, rather than subtracting off the predictor, which would make energy conservation impossible. We also derive an encoding of the vector-quantized codewords that takes advantage of their non-uniform distribution. We show that the resulting technique outperforms scalar quantization by an average of 0.90 dB on still images, equivalent to a 24.8% reduction in bitrate at equal quality, while for videos, the improvement averages 0.83 dB, equivalent to a 13.7% reduction in bitrate.
Stability of Horndeski vector-tensor interactions
Energy Technology Data Exchange (ETDEWEB)
Jiménez, Jose Beltrán [Centre for Cosmology, Particle Physics and Phenomenology, Institute of Mathematics and Physics, Louvain University, 2 Chemin du Cyclotron, Louvain-la-Neuve, 1348 (Belgium); Durrer, Ruth; Heisenberg, Lavinia [Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, Genève 4, CH-1211 (Switzerland); Thorsrud, Mikjel, E-mail: jose.beltran@uclouvain.be, E-mail: ruth.durrer@unige.ch, E-mail: lavinia.heisenberg@unige.ch, E-mail: mikjel.thorsrud@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, Oslo, N-0315 (Norway)
2013-10-01
We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: the standard Maxwell kinetic term and a coupling to the dual Riemann tensor. Furthermore, the vector sector respects the U(1) gauge symmetry and the theory contains only one free parameter, M{sup 2}, that controls the strength of the non-minimal coupling. We explore the theory in a de Sitter spacetime and study the presence of instabilities and show that it corresponds to an attractor solution in the presence of the vector field. We also investigate the cosmological evolution and stability of perturbations in a general FLRW spacetime. We find that a sufficient condition for the absence of ghosts is M{sup 2} > 0. Moreover, we study further constraints coming from imposing the absence of Laplacian instabilities. Finally, we study the stability of the theory in static and spherically symmetric backgrounds (in particular, Schwarzschild and Reissner-Nordström-de Sitter). We find that the theory, quite generally, do have ghosts or Laplacian instabilities in regions of spacetime where the non-minimal interaction dominates over the Maxwell term. We also calculate the propagation speed in these spacetimes and show that superluminality is a quite generic phenomenon in this theory.
Stability of Horndeski vector-tensor interactions
Jiménez, Jose Beltrán; Heisenberg, Lavinia; Thorsrud, Mikjel
2013-01-01
We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: the standard Maxwell kinetic term and a coupling to the dual Riemann tensor. Furthermore, the vector sector respects the U(1) gauge symmetry and the theory contains only one free parameter, M^2, that controls the strength of the non-minimal coupling. We explore the theory in a de Sitter spacetime and study the presence of instabilities and show that it corresponds to an attractor solution in the presence of the vector field. We also investigate the cosmological evolution and stability of perturbations in a general FLRW spacetime. We find that a sufficient condition for the absence of ghosts is M^2>0. Moreover, we study further constraints coming from imposing the absence of Laplacian instabilities. Finally, we study the stability of the theory in static and spherica...
Stability of Horndeski vector-tensor interactions
Beltrán Jiménez, Jose; Durrer, Ruth; Heisenberg, Lavinia; Thorsrud, Mikjel
2013-10-01
We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: the standard Maxwell kinetic term and a coupling to the dual Riemann tensor. Furthermore, the vector sector respects the U(1) gauge symmetry and the theory contains only one free parameter, M2, that controls the strength of the non-minimal coupling. We explore the theory in a de Sitter spacetime and study the presence of instabilities and show that it corresponds to an attractor solution in the presence of the vector field. We also investigate the cosmological evolution and stability of perturbations in a general FLRW spacetime. We find that a sufficient condition for the absence of ghosts is M2 > 0. Moreover, we study further constraints coming from imposing the absence of Laplacian instabilities. Finally, we study the stability of the theory in static and spherically symmetric backgrounds (in particular, Schwarzschild and Reissner-Nordström-de Sitter). We find that the theory, quite generally, do have ghosts or Laplacian instabilities in regions of spacetime where the non-minimal interaction dominates over the Maxwell term. We also calculate the propagation speed in these spacetimes and show that superluminality is a quite generic phenomenon in this theory.
Support vector machine applied in QSAR modelling
Institute of Scientific and Technical Information of China (English)
MEI Hu; ZHOU Yuan; LIANG Guizhao; LI Zhiliang
2005-01-01
Support vector machine (SVM), partial least squares (PLS), and Back-Propagation artificial neural network (ANN) were employed to establish QSAR models of 2 dipeptide datasets. In order to validate predictive capabilities on external dataset of the resulting models, both internal and external validations were performed. The division of dataset into both training and test sets was carried out by D-optimal design. The results showed that support vector machine (SVM) behaved well in both calibration and prediction. For the dataset of 48 bitter tasting dipeptides (BTD), the results obtained by support vector regression (SVR) were superior to that by PLS in both calibration and prediction. When compared with BP artificial neural network, SVR showed less calibration power but more predictive capability. For the dataset of angiotensin-converting enzyme (ACE) inhibitors, the results obtained by support vector machine (SVM) regression were equivalent to those by PLS and BP artificial neural network. In both datasets, SVR using linear kernel function behaved well as that using radial basis kernel function. The results showed that there is wide prospect for the application of support vector machine (SVM) into QSAR modeling.
Intersectoral approaches to dengue vector control.
Kay, B H
1994-12-01
Medical entomology in the context of urban vector control, especially for dengue, can be likened to the tail of a dog. Vertically structured Aedes aegypti campaigns such as run by Gorgas and Soper earlier this century relied on sufficient legislative backing for vector control to ensure that the tail was capable of wagging the dog. Under these conditions, especially where individual rights do not intrude, vertical programs will be successful. The global expansion of dengue, dengue hemorrhagic fever and its vectors, plus growing trends towards urban/periurban living indicate a more serious scenario than at present. In 1987, the Brundtland Report: "Our Common Future" decried sectoralism in problem solving. Following the United Nations Conference on Environment and Development (UNCED) in 1992, the resulting Commission on Sustainable Development has promoted the intersectoral message of health, environment and development. The WHO/FAO/UNEP/UNCHS Panel of Experts on Environmental Management for Vector Control has promoted this for some time and is attempting to build multidisciplinary projects against urban vector borne disease. Adequate solid waste management and recycling will reduce numbers of water bearing containers infested with Aedes aegypti and provision of reliable piped water supplies will impact heavily on infested water storage containers. Both should be encouraged as viable control options. For much of the world, vertical programs have been reported as prohibitively expensive, and unacceptable intrusion on human rights and thus unsustainable in the modern economic context. However there are successful modern examples.(ABSTRACT TRUNCATED AT 250 WORDS)
Dynamical Symmetry Breaking with Vector Bosons
Cynolter, G; Pócsik, G
2004-01-01
In the standard model of electroweak interactions the Higgs doublet is replaced by a complex vector doublet and a real vector singlet. The gauge symmetry is broken dynamically by a mixed condensate of the doublet and singlet vector fields. Gauge fields get their usual standard model masses by condensation. The new vector matter fields become massive by their gauge invariant selfcouplings and expected to have masses of few hundred GeV. Fermions are assigned to the gauge group in the usual manner. Fermion masses are coming from a gauge invariant fermion-vector field interaction by a mixed condensat, the Kobayashi-Maskawa description is unchanged. Perturbative unitarity estimates show that the model is valid up to 2-3 TeV. It is shown that from the new matter fields a large number of spin-one particle pairs is expected at future high energy e^{+}e^{-} linear colliders of 500-1500 GeV. The inclusive production cross section of new particle pairs is presented for hadron colliders, while at the Tevatron the new par...
Improved Coinfection with Amphotropic Pseudotyped Retroviral Vectors
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Yuehong Wu
2009-01-01
Full Text Available Amphotropic pseudotyped retroviral vectors have typically been used to infect target cells without prior concentration. Although this can yield high rates of infection, higher rates may be needed where highly efficient coinfection of two or more vectors is needed. In this investigation we used amphotropic retroviral vectors produced by the Plat-A cell line and studied coinfection rates using green and red fluorescent proteins (EGFP and dsRed2. Target cells were primary human fibroblasts (PHF and 3T3 cells. Unconcentrated vector preparations produced a coinfection rate of ∼4% (defined as cells that are both red and green as a percentage of all cells infected. Optimized spinoculation, comprising centrifugation at 1200 g for 2 hours at 15∘C, increased the coinfection rate to ∼10%. Concentration by centrifugation at 10,000 g or by flocculation using Polybrene increased the coinfection rate to ∼25%. Combining the two processes, concentration by Polybrene flocculation and optimized spinoculation, increased the coinfection rate to 35% (3T3 or >50% (PHF. Improved coinfection should be valuable in protocols that require high transduction by combinations of two or more retroviral vectors.
Reduced Order Model Basis Vector Generation: Generates Basis Vectors fro ROMs
Energy Technology Data Exchange (ETDEWEB)
2016-03-03
libROM is a library that implements order reduction via singular value decomposition (SVD) of sampled state vectors. It implements 2 parallel, incremental SVD algorithms and one serial, non-incremental algorithm. It also provides a mechanism for adaptive sampling of basis vectors.
Energy Technology Data Exchange (ETDEWEB)
Adachi, Masaaki; Ogasawara, Shinobu; Kume, Etsuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishizuki, Shigeru; Nemoto, Toshiyuki; Kawasaki, Nobuo; Kawai, Wataru [Fujitsu Ltd., Tokyo (Japan); Yatake, Yo-ichi [Hitachi Ltd., Tokyo (Japan)
2001-02-01
Several computer codes in the nuclear field have been vectorized, parallelized and trans-ported on the FUJITSU VPP500 system, the AP3000 system, the SX-4 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 18 codes in fiscal 1999. These results are reported in 3 parts, i.e., the vectorization and the parallelization part on vector processors, the parallelization part on scalar processors and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of Relativistic Molecular Orbital Calculation code RSCAT, a microscopic transport code for high energy nuclear collisions code JAM, three-dimensional non-steady thermal-fluid analysis code STREAM, Relativistic Density Functional Theory code RDFT and High Speed Three-Dimensional Nodal Diffusion code MOSRA-Light on the VPP500 system and the SX-4 system are described. (author)
Test of Understanding of Vectors: A Reliable Multiple-Choice Vector Concept Test
Barniol, Pablo; Zavala, Genaro
2014-01-01
In this article we discuss the findings of our research on students' understanding of vector concepts in problems without physical context. First, we develop a complete taxonomy of the most frequent errors made by university students when learning vector concepts. This study is based on the results of several test administrations of open-ended…
Auto-tuning Dense Vector and Matrix-vector Operations for Fermi GPUs
DEFF Research Database (Denmark)
Sørensen, Hans Henrik Brandenborg
2012-01-01
In this paper, we consider the automatic performance tuning of dense vector and matrix-vector operations on GPUs. Such operations form the backbone of level 1 and level 2 routines in the Basic Linear Algebra Subroutines (BLAS) library and are therefore of great importance in many scientific...
A viral protease relocalizes in the presence of the vector to promote vector performance
Bak, Aurélie; Cheung, Andrea L.; Yang, Chunling; Whitham, Steven A.; Casteel, Clare L.
2017-01-01
Vector-borne pathogens influence host characteristics relevant to host–vector contact, increasing pathogen transmission and survival. Previously, we demonstrated that infection with Turnip mosaic virus, a member of one of the largest families of plant-infecting viruses, increases vector attraction and reproduction on infected hosts. These changes were due to a single viral protein, NIa-Pro. Here we show that NIa-Pro responds to the presence of the aphid vector during infection by relocalizing to the vacuole. Remarkably, vacuolar localization is required for NIa-Pro's ability to enhance aphid reproduction on host plants, vacuole localization disappears when aphids are removed, and this phenomenon occurs for another potyvirus, Potato virus Y, suggesting a conserved role for the protein in vector–host interactions. Taken together, these results suggest that potyviruses dynamically respond to the presence of their vectors, promoting insect performance and transmission only when needed. PMID:28205516
Concircular $\\pi$-Vector Fields and Special Finsler Spaces
Youssef, Nabil L.; Soleiman, A
2012-01-01
The aim of the present paper is to investigate intrinsically the notion of a concircular $\\pi$-vector field in Finsler geometry. This generalizes the concept of a concircular vector field in Riemannian geometry and the concept of a concurrent vector field in Finsler geometry. Some properties of concircular $\\pi$-vector fields are obtained. Different types of recurrence are discussed. The effect of the existence of a concircular $\\pi$-vector field on some important special Finsler spaces is in...
GENERALIZED VECTOR VARIATIONAL-TYPE INEQUALITIES IN FC-SPACES
Institute of Scientific and Technical Information of China (English)
FANG Min; DING Xie-ping
2006-01-01
A class of generalized vector variational-type inequality problems (GVVTIP) are studied in FC-spaces, which includes the most of vector equilibrium problems, vector variational inequality problems, generalized vector equilibrium problems and generalized vector variational inequality problem as special cases. By using F-KKM theorem,some new existence results for GVVTIP are established in noncompact FC-space. As consequences, some recent known results in literature are obtained under much weaker assumption.
Emergence and prevalence of human vector-borne diseases in sink vector populations.
Directory of Open Access Journals (Sweden)
Guilhem Rascalou
Full Text Available Vector-borne diseases represent a major public health concern in most tropical and subtropical areas, and an emerging threat for more developed countries. Our understanding of the ecology, evolution and control of these diseases relies predominantly on theory and data on pathogen transmission in large self-sustaining 'source' populations of vectors representative of highly endemic areas. However, there are numerous places where environmental conditions are less favourable to vector populations, but where immigration allows them to persist. We built an epidemiological model to investigate the dynamics of six major human vector borne-diseases in such non self-sustaining 'sink' vector populations. The model was parameterized through a review of the literature, and we performed extensive sensitivity analysis to look at the emergence and prevalence of the pathogen that could be encountered in these populations. Despite the low vector abundance in typical sink populations, all six human diseases were able to spread in 15-55% of cases after accidental introduction. The rate of spread was much more strongly influenced by vector longevity, immigration and feeding rates, than by transmission and virulence of the pathogen. Prevalence in humans remained lower than 5% for dengue, leishmaniasis and Japanese encephalitis, but substantially higher for diseases with longer duration of infection; malaria and the American and African trypanosomiasis. Vector-related parameters were again the key factors, although their influence was lower than on pathogen emergence. Our results emphasize the need for ecology and evolution to be thought in the context of metapopulations made of a mosaic of sink and source habitats, and to design vector control program not only targeting areas of high vector density, but working at a larger spatial scale.
Heavy vector and axial-vector mesons in hot and dense asymmetric strange hadronic matter
Kumar, Arvind; Chhabra, Rahul
2015-09-01
We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector (D*,Ds*,B*,Bs*) and axial-vector (D1,D1 s,B1,B1 s) mesons, using the chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In the quantum chromodynamics sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons are written in terms of quark and gluon condensates. These quark and gluon condensates are evaluated in the present work within the chiral SU(3) model, through the medium modification of scalar-isoscalar fields σ and ζ , the scalar-isovector field δ , and the scalar dilaton field χ , in the strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail, the masses and decay constants of heavy vector and axial-vector mesons are affected significantly from isospin asymmetry and the strangeness fraction of the medium, and these modifications may influence the experimental observables produced in heavy-ion collision experiments. The results of present investigations of in-medium properties of vector and axial-vector mesons at finite density and temperature of strange hadronic medium may be helpful for understanding the experimental data from heavy-ion collision experiments in particular for the compressed baryonic matter (CBM) experiment of the FAIR facility at GSI, Germany.
Axial symmetry and conformal Killing vectors
Mars, M; Mars, Marc; Senovilla, Jose M.M.
1993-01-01
Axisymmetric spacetimes with a conformal symmetry are studied and it is shown that, if there is no further conformal symmetry, the axial Killing vector and the conformal Killing vector must commute. As a direct consequence, in conformally stationary and axisymmetric spacetimes, no restriction is made by assuming that the axial symmetry and the conformal timelike symmetry commute. Furthermore, we prove that in axisymmetric spacetimes with another symmetry (such as stationary and axisymmetric or cylindrically symmetric spacetimes) and a conformal symmetry, the commutator of the axial Killing vector with the two others mush vanish or else the symmetry is larger than that originally considered. The results are completely general and do not depend on Einstein's equations or any particular matter content.
Genetic Modification of Baculovirus Expression Vectors
Institute of Scientific and Technical Information of China (English)
Shu-fen Li; Hua-lin Wang; Zhi-hong Hu; Fei Deng
2012-01-01
As a protein expression vector,the baculovirus demonstrates many advantages over other vectors.With the development of biotechnology,baculoviral vectors have been genetically modified to facilitate high level expression of heterologous proteins in both insect and mammalian cells.These modifications include utilization of different promoters and signal peptides,deletion or replacement of viral genes for increasing protein secretion,integration of polycistronic expression cassette for producing protein complexes,and baculovirus pseudotyping,promoter accommodation or surface display for enhancing mammalian cell targeting gene delivery.This review summarizes the development and the current state of art of the baculovirus expression system.Further development of baculovirus expression systems will make them even more feasible and accessible for advanced applications.
Improving DNA vaccine performance through vector design.
Williams, James A
2014-01-01
DNA vaccines are a rapidly deployed next generation vaccination platform for treatment of human and animal disease. DNA delivery devices, such as electroporation and needle free jet injectors, are used to increase gene transfer. This results in higher antigen expression which correlates with improved humoral and cellular immunity in humans and animals. This review highlights recent vector and transgene design innovations that improve DNA vaccine performance. These new vectors improve antigen expression, increase plasmid manufacturing yield and quality in bioreactors, and eliminate antibiotic selection and other potential safety issues. A flowchart for designing synthetic antigen transgenes, combining antigen targeting, codon-optimization and bioinformatics, is presented. Application of improved vectors, of antibiotic free plasmid production, and cost effective manufacturing technologies will be critical to ensure safety, efficacy, and economically viable manufacturing of DNA vaccines currently under development for infectious disease, cancer, autoimmunity, immunotolerance and allergy indications.
Partial Transfer Entropy on Rank Vectors
Kugiumtzis, Dimitris
2013-01-01
For the evaluation of information flow in bivariate time series, information measures have been employed, such as the transfer entropy (TE), the symbolic transfer entropy (STE), defined similarly to TE but on the ranks of the components of the reconstructed vectors, and the transfer entropy on rank vectors (TERV), similar to STE but forming the ranks for the future samples of the response system with regard to the current reconstructed vector. Here we extend TERV for multivariate time series, and account for the presence of confounding variables, called partial transfer entropy on ranks (PTERV). We investigate the asymptotic properties of PTERV, and also partial STE (PSTE), construct parametric significance tests under approximations with Gaussian and gamma null distributions, and show that the parametric tests cannot achieve the power of the randomization test using time-shifted surrogates. Using simulations on known coupled dynamical systems and applying parametric and randomization significance tests, we s...
Weyl node with random vector potential
Sbierski, Björn; Decker, Kevin S. C.; Brouwer, Piet W.
2016-12-01
We study Weyl semimetals in the presence of generic disorder, consisting of a random vector potential as well as a random scalar potential. We derive renormalization group flow equations to second order in the disorder strength. These flow equations predict a disorder-induced phase transition between a pseudoballistic weak-disorder phase and a diffusive strong-disorder phase for a sufficiently strong random scalar potential or for a pure three-component random vector potential. We verify these predictions using a numerical study of the density of states near the Weyl point and of quantum transport properties at the Weyl point. In contrast, for a pure single-component random vector potential, the diffusive strong-disorder phase is absent.
Insect Vectors of Rice Yellow Mottle Virus
Directory of Open Access Journals (Sweden)
Augustin Koudamiloro
2015-01-01
Full Text Available Rice yellow mottle virus (RYMV is the major viral constraint to rice production in Africa. RYMV was first identified in 1966 in Kenya and then later in most African countries where rice is grown. Several studies have been conducted so far on its evolution, pathogenicity, resistance genes, and especially its dissemination by insects. Many of these studies showed that, among RYMV vectors, insects especially leaf-feeders found in rice fields are the major source of virus transmission. Many studies have shown that the virus is vectored by several insect species in a process of a first ingestion of leaf material and subsequent transmission in following feedings. About forty insect species were identified as vectors of RYMV since 1970 up to now. They were essentially the beetles, grasshoppers, and the leafhoppers. For this review, we presented the chronology of their identification. Also, the biology, ecology, host range, distribution, and caused damage of these insects were briefly summarized.
Measuring vector magnetic fields in solar prominences
Suárez, D Orozco; Bueno, J Trujillo
2012-01-01
We present spectropolarimetric observations in the He I 1083.0 nm multiplet of a quiescent, hedgerow solar prominence. The data were taken with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope at the Observatorio del Teide (Tenerife; Canary Islands; Spain). The observed He I circular and linear polarization signals are dominated by the Zeeman effect and by atomic level polarization and the Hanle effect, respectively. These observables are sensitive to the strength and orientation of the magnetic field vector at each spatial point of the field of view. We determine the magnetic field vector of the prominence by applying the HAZEL inversion code to the observed Stokes profiles. We briefly discuss the retrieved magnetic field vector configuration.
Replicon RNA Viral Vectors as Vaccines
Lundstrom, Kenneth
2016-01-01
Single-stranded RNA viruses of both positive and negative polarity have been used as vectors for vaccine development. In this context, alphaviruses, flaviviruses, measles virus and rhabdoviruses have been engineered for expression of surface protein genes and antigens. Administration of replicon RNA vectors has resulted in strong immune responses and generation of neutralizing antibodies in various animal models. Immunization of mice, chicken, pigs and primates with virus-like particles, naked RNA or layered DNA/RNA plasmids has provided protection against challenges with lethal doses of infectious agents and administered tumor cells. Both prophylactic and therapeutic efficacy has been achieved in cancer immunotherapy. Moreover, recombinant particles and replicon RNAs have been encapsulated by liposomes to improve delivery and targeting. Replicon RNA vectors have also been subjected to clinical trials. Overall, immunization with self-replicating RNA viruses provides high transient expression levels of antigens resulting in generation of neutralizing antibody responses and protection against lethal challenges under safe conditions. PMID:27827980
Molecular Epidemiology for Vector Research on Leishmaniasis
Directory of Open Access Journals (Sweden)
Hirotomo Kato
2010-03-01
Full Text Available Leishmaniasis is a protozoan disease caused by the genus Leishmania transmitted by female phlebotomine sand flies. Surveillance of the prevalence of Leishmania and responsive vector species in endemic and surrounding areas is important for predicting the risk and expansion of the disease. Molecular biological methods are now widely applied to epidemiological studies of infectious diseases including leishmaniasis. These techniques are used to detect natural infections of sand fly vectors with Leishmania protozoa and are becoming powerful tools due to their sensitivity and specificity. Recently, genetic analyses have been performed on sand fly species and genotyping using PCR-RFLP has been applied to the sand fly taxonomy. In addition, a molecular mass screening method has been established that enables both sand fly species and natural leishmanial infections to be identified simultaneously in hundreds of sand flies with limited effort. This paper reviews recent advances in the study of sand flies, vectors of leishmaniasis, using molecular biological approaches.
Interactions between parasites and insects vectors
Directory of Open Access Journals (Sweden)
Hilary Hurd
1994-01-01
Full Text Available This review stresses the importance of studies that will provide a basic understanding of the pathology of parasite-infected vector insects. This knowledge should be a vital component of the very focussed initiatives currently being funded in the areas of vector control. Vector fecundity reduction is discussed as an example of such pathology. Underlying mechanisms are being investigated in a model system, Hymenolepis diminuta-infected Tenebrio molitor and in Onchocerca-infected blackflies and Plasmodium-infected Anopheles stephensi. In all cases, host vitellogenesis is disrupted by the parasite and, in the tapeworm/beetle model, interaction between the parasite and the endocrine control of the insect's reproductive physiology has been demonstrated.
Review of Scalars, Vectors, Tensors, and Dyads
Schnack, Dalton D.
In MHD, we will deal with relationships between quantities such as the magnetic field and the velocity that have both magnitude and direction. These quantities are examples of vectors (or, as we shall soon see, pseudovectors). The basic concepts of scalar and vector quantities are introduced early in any scientific education. However, to formulate the laws of MHD precisely, it will be necessary to generalize these ideas and to introduce the less familiar concepts of matrices, tensors, and dyads. The ability to understand and manipulate these abstract mathematical concepts is essential to learning MHD. Therefore, for the sake of both reference and completeness, this lecture is about the mathematical properties of scalars, vectors, matrices, tensors, and dyads. If you are already an expert, or think you are, please skip class and go on to Lecture 3. You can always refer back here if needed!
Covariant Lyapunov vectors for rigid disk systems.
Bosetti, Hadrien; Posch, Harald A
2010-10-05
We carry out extensive computer simulations to study the Lyapunov instability of a two-dimensional hard-disk system in a rectangular box with periodic boundary conditions. The system is large enough to allow the formation of Lyapunov modes parallel to the x-axis of the box. The Oseledec splitting into covariant subspaces of the tangent space is considered by computing the full set of covariant perturbation vectors co-moving with the flow in tangent space. These vectors are shown to be transversal, but generally not orthogonal to each other. Only the angle between covariant vectors associated with immediate adjacent Lyapunov exponents in the Lyapunov spectrum may become small, but the probability of this angle to vanish approaches zero. The stable and unstable manifolds are transverse to each other and the system is hyperbolic.
Comparaciones Multivariantes de Vectores Aleatorios con Aplicaciones
2012-01-01
El resultado de un experimento es variable y está modelado por variables y vectores aleatorios. Comúnmente, las comparaciones entre están cantidades aleatorias están basadas en algunas medidas asociadas, pero a menudo no son demasiado informativas. En este caso, los órdenes estocásticos proporcionan una comparación más completa. A veces, estamos interesados en estudiar propiedades de una variable o vector aleatorio, es decir, sus propiedades de envejecimiento. Los órdenes estocásticos son tam...
Retrotransposon vectors for gene delivery in plants
Directory of Open Access Journals (Sweden)
Hou Yi
2010-08-01
Full Text Available Abstract Background Retrotransposons are abundant components of plant genomes, and although some plant retrotransposons have been used as insertional mutagens, these mobile genetic elements have not been widely exploited for plant genome manipulation. In vertebrates and yeast, retrotransposons and retroviruses are routinely altered to carry additional genes that are copied into complementary (cDNA through reverse transcription. Integration of cDNA results in gene delivery; recombination of cDNA with homologous chromosomal sequences can create targeted gene modifications. Plant retrotransposon-based vectors, therefore, may provide new opportunities for plant genome engineering. Results A retrotransposon vector system was developed for gene delivery in plants based on the Tnt1 element from Nicotiana tabacum. Mini-Tnt1 transfer vectors were constructed that lack coding sequences yet retain the 5' and 3' long terminal repeats (LTRs and adjacent cis sequences required for reverse transcription. The internal coding region of Tnt1 was replaced with a neomycin phosphotransferase gene to monitor replication by reverse transcription. Two different mini-Tnt1 s were developed: one with the native 5' LTR and the other with a chimeric 5' LTR that had the first 233 bp replaced by the CaMV 35 S promoter. After transfer into tobacco protoplasts, both vectors undergo retrotransposition using GAG and POL proteins provided in trans by endogenous Tnt1 elements. The transposition frequencies of mini-Tnt1 vectors are comparable with native Tnt1 elements, and like the native elements, insertion sites are within or near coding sequences. In this paper, we provide evidence that template switching occurs during mini-Tnt1 reverse transcription, indicating that multiple copies of Tnt1 mRNA are packaged into virus-like particles. Conclusions Our data demonstrate that mini-Tnt1 vectors can replicate efficiently in tobacco cells using GAG and POL proteins provided in trans by
Vector Fields and Flows on Differentiable Stacks
DEFF Research Database (Denmark)
A. Hepworth, Richard
2009-01-01
This paper introduces the notions of vector field and flow on a general differentiable stack. Our main theorem states that the flow of a vector field on a compact proper differentiable stack exists and is unique up to a uniquely determined 2-cell. This extends the usual result on the existence...... and uniqueness of flows on a manifold as well as the author's existing results for orbifolds. It sets the scene for a discussion of Morse Theory on a general proper stack and also paves the way for the categorification of other key aspects of differential geometry such as the tangent bundle and the Lie algebra...
[Conflicts and vector-borne diseases
DEFF Research Database (Denmark)
Bygbjerg, Ib Christian
2010-01-01
Based on literature and personal experiences, vector-borne diseases and conflicts are reviewed. Simple rapid diagnostic tests for three important parasitoses are available. Resort is often made to case definitions and to presumptive treatment. Resistance is an emerging problem. Vaccines are still...... not available for most diseases. Promising preventive methods, including long-lasting impregnated bed-nets and tents, are available. War has been an impetus for disclosing life-cycles of vector-borne diseases and for control methods; peace, reconciliation and poverty reduction are required to achieve lasting...
Diffractive vector meson leptoproduction and spin effects
Goloskokov, S V
2006-01-01
We analyse spin effects in diffractive vector meson leptoproduction at small $x$ on the basis of the generalized parton distribution (GPD) approach. We take into account quark transverse degrees of freedom in the hard subprocess. We calculate amplitudes for the longitudinally and transversely polarized photons and vector mesons. Our results on the cross section and spin density matrix elements (SDME) are in fair agreement with the DESY experiments. Predictions for HERMES and COMPASS energy range are made. The predicted double spin longitudinal $A_{LL}$ asymmetry is not small at HERMES energies
Vector Fields European user group meeting
2007-01-01
The "Vector Fields European user group meeting" will take place at CERN on 26 and 27 September 2007. Within this framework two workshops are organized at the CERN Training Centre: 24 September 2007 Modelling Magnets with Opera 25 September 2007 Modelling of Charged Particle Beam Devices with Opera If you are interested in attending the workshop or the user group meeting please contact Julie Shepherd (Vector Fields) or Pierre Baehler (CERN) directly at: Julie.Shepherd@vectorfields.co.uk, +44 (0) 1865 854933 or +44 (0) 1865 370151 Pierre.Baehler@cern.ch, 75016 / 160156.
Vector Meson Masses in Chiral Perturbation Theory
Bijnens, J; Talavera, P
1997-01-01
We discuss the vector meson masses within the context of Chiral Perturbation Theory performing an expansion in terms of the momenta, quark masses and 1/Nc. We extend the previous analysis to include isospin breaking effects and also include up to order p^4. We discuss vector meson chiral perturbation theory in some detail and present a derivation from a relativistic lagrangian. The unknown coefficients are estimated in various ways. We also discuss the relevance of electromagnetic corrections and the implications of the present calculation for the determination of quark masses.
Novel cloning vectors for Bacillus thuringiensis.
Baum, J A; Coyle, D M; Gilbert, M P; Jany, C S; Gawron-Burke, C
1990-01-01
Seven replication origins from resident plasmids of Bacillus thuringienis subsp. kurstaki HD263 and HD73 were cloned in Escherichia coli. Three of these replication origins, originating from plasmids of 43, 44, and 60 MDa, were used to construct a set of compatible shuttle vectors that exhibit structural and segregational stability in the Cry- strain B. thuringiensis HD73-26. These shuttle vectors, pEG597, pEG853, and pEG854, were designed with rare restriction sites that permit various adapt...
Problem signatures from enhanced vector autoregressive modeling
Andriamanalimanana, Bruno R.; Sengupta, Saumen S.
2001-09-01
The work reported in this paper concerns the enhancement of mutivariate autoregressive (AR) models with geometric shape analysis data and stochastic causal relations. The study aims at producing numerical signatures characterizing operating problems, from multivariate time series of data collected in an application and operating environment domain. Since the information content of an AR model does not appear sufficient to characterize observed vector values fully, both geometric and stochastic modeling techniques are applied to refine causal inferences further. The specific application domain used for this study is real-time network traffic monitoring. However, other domains utilizing vector models might benefit as well. A partial Java implementation is being used for experimentation.
Variable ordering structures in vector optimization
Eichfelder, Gabriele
2014-01-01
This book provides an introduction to vector optimization with variable ordering structures, i.e., to optimization problems with a vector-valued objective function where the elements in the objective space are compared based on a variable ordering structure: instead of a partial ordering defined by a convex cone, we see a whole family of convex cones, one attached to each element of the objective space. The book starts by presenting several applications that have recently sparked new interest in these optimization problems, and goes on to discuss fundamentals and important results on a wide ra
Craig, Nathaniel; Knapen, Simon; Longhi, Pietro; Strassler, Matthew
2016-07-01
We present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.
Craig, Nathaniel; Longhi, Pietro; Strassler, Matthew
2016-01-01
We present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.
Masquerade Detection Using Support Vector Machine
Institute of Scientific and Technical Information of China (English)
YANG Min; WANG Li-na; ZHANG Huan-guo; CHEN Wei
2005-01-01
A new method using support vector data description (SVDD) to distinguish legitimate users from masqueraders based on UNIX user command sequences is proposed. Sliding windows are used to get low detection delay.Experiments demonstrate that the detection effect using en riched sequences is better than that of using truncated sequences. As a SVDD profile is composed of a small amount of support vectors, our SVDD-based method can achieve computation and storage advantage when the detection performance is similar to existing method.
Integrated vector management for malaria control
Directory of Open Access Journals (Sweden)
Impoinvil Daniel E
2008-12-01
Full Text Available Abstract Integrated vector management (IVM is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1 evidence-based decision-making, 2 integrated approaches 3, collaboration within the health sector and with other sectors, 4 advocacy, social mobilization, and legislation, and 5 capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress has been made in developing and promoting IVM for national malaria control programmes in Africa at a time when successful malaria control programmes are scaling-up with insecticide-treated nets (ITN and/or indoor residual spraying (IRS coverage. While interventions using only ITNs and/or IRS successfully reduce transmission intensity and the burden of malaria in many situations, it is not clear if these interventions alone will achieve those critical low levels that result in malaria elimination. Despite the successful employment of comprehensive integrated malaria control programmes, further strengthening of vector control components through IVM is relevant, especially during the "end-game" where control is successful and further efforts are required to go from low transmission situations to sustained local and country-wide malaria elimination. To meet this need and to ensure sustainability of control efforts, malaria control programmes should strengthen their capacity to use data for decision-making with respect to evaluation of current vector control programmes, employment of additional vector control tools in conjunction with ITN/IRS tactics, case-detection and treatment strategies, and determine how much and what types of vector control and interdisciplinary input are required to achieve malaria elimination. Similarly, on a global scale, there is a need for continued research to identify and evaluate new tools for vector control that can be integrated with
Parasitic diseases in humans transmitted by vectors.
Cholewiński, Marcin; Derda, Monika; Hadaś, Edward
2015-01-01
Despite the considerable progress of medicine, parasitic diseases still pose a great threat to human health and life. Among parasitic diseases, those transmitted by vectors, mainly arthropods, play a particular role. These diseases occur most frequently in the poorest countries and affect a vast part of the human population. They include malaria, babesiosis, trypanosomiasis, leishmaniasis and filariasis. This study presents those vector-transmitted diseases that are responsible for the greatest incidence and mortality of people on a global scale. Attention is focused primarily on diseases transmitted by mosquitoes, flies, Hemiptera and ticks.
Stability Analysis of Path-vector Routing
Dimitri, Papadimitriou
2012-01-01
Most studies on path-vector routing stability have been conducted empirically by means of ad-hoc analysis of BGP data traces. None of them consider prior specification of an analytic method including the use of stability measurement metrics for the systematic analysis of BGP traces and associated meta-processing for determining the local state of the routing system. In this paper, we define a set of metrics that characterize the local stability properties of path-vector routing such as BGP (Border Gateway Protocol). By means of these stability metrics, we propose a method to analyze the effects of BGP policy- and protocol-induced instability on local routers.
Analysis of Path-vector Routing Stability
Dimitri, Papadimitriou
2012-01-01
Most studies on path-vector routing stability have been conducted empirically by means of ad-hoc analysis of BGP data traces. None of them consider prior specification of an analytic method including the use of stability measurement metrics for the systematic analysis of BGP traces and associated meta-processing for determining the local state of the routing system. In this paper, we define a set of metrics that characterize the local stability properties of path-vector routing such as BGP (Border Gateway Protocol). By means of these stability metrics, we propose a method to analyze the effects of BGP policy- and protocol-induced instability on local routers.
Directory of Open Access Journals (Sweden)
Kenichi W Okamoto
2016-03-01
Full Text Available Many vector-borne diseases lack effective vaccines and medications, and the limitations of traditional vector control have inspired novel approaches based on using genetic engineering to manipulate vector populations and thereby reduce transmission. Yet both the short- and long-term epidemiological effects of these transgenic strategies are highly uncertain. If neither vaccines, medications, nor transgenic strategies can by themselves suffice for managing vector-borne diseases, integrating these approaches becomes key. Here we develop a framework to evaluate how clinical interventions (i.e., vaccination and medication can be integrated with transgenic vector manipulation strategies to prevent disease invasion and reduce disease incidence. We show that the ability of clinical interventions to accelerate disease suppression can depend on the nature of the transgenic manipulation deployed (e.g., whether vector population reduction or replacement is attempted. We find that making a specific, individual strategy highly effective may not be necessary for attaining public-health objectives, provided suitable combinations can be adopted. However, we show how combining only partially effective antimicrobial drugs or vaccination with transgenic vector manipulations that merely temporarily lower vector competence can amplify disease resurgence following transient suppression. Thus, transgenic vector manipulation that cannot be sustained can have adverse consequences-consequences which ineffective clinical interventions can at best only mitigate, and at worst temporarily exacerbate. This result, which arises from differences between the time scale on which the interventions affect disease dynamics and the time scale of host population dynamics, highlights the importance of accounting for the potential delay in the effects of deploying public health strategies on long-term disease incidence. We find that for systems at the disease-endemic equilibrium, even
Predictive vector quantization using a neural network approach
Mohsenian, Nader; Rizvi, Syed A.; Nasrabadi, Nasser M.
1993-07-01
A new predictive vector quantization (PVQ) technique capable of exploring the nonlinear dependencies in addition to the linear dependencies that exist between adjacent blocks (vectors) of pixels is introduced. The two components of the PVQ scheme, the vector predictor and the vector quantizer, are implemented by two different classes of neural networks. A multilayer perceptron is used for the predictive component and Kohonen self- organizing feature maps are used to design the codebook for the vector quantizer. The multilayer perceptron uses the nonlinearity condition associated with its processing units to perform a nonlinear vector prediction. The second component of the PVQ scheme vector quantizers the residual vector that is formed by subtracting the output of the perceptron from the original input vector. The joint-optimization task of designing the two components of the PVQ scheme is also achieved. Simulation results are presented for still images with high visual quality.
Constructions of Vector-Valued Filters and Vector-Valued Wavelets
Directory of Open Access Journals (Sweden)
Jianxun He
2012-01-01
Full Text Available Let a =(a1,a2,…,am∈ℂm be an m-dimensional vector. Then, it can be identified with an m×m circulant matrix. By using the theory of matrix-valued wavelet analysis (Walden and Serroukh, 2002, we discuss the vector-valued multiresolution analysis. Also, we derive several different designs of finite length of vector-valued filters. The corresponding scaling functions and wavelet functions are given. Specially, we deal with the construction of filters on symmetric matrix-valued functions space.
Use of vectors in sequence analysis.
Ishikawa, T; Yamamoto, K; Yoshikura, H
1987-10-01
Applications of the vector diagram, a new type of representation of protein structure, in homology search of various proteins including oncogene products are presented. The method takes account of various kinds of information concerning the properties of amino acids, such as Chou and Fasman's probability data. The method can detect conformational similarities of proteins which may not be detected by the conventional programs.
Image compression using address-vector quantization
Nasrabadi, Nasser M.; Feng, Yushu
1990-12-01
A novel vector quantization scheme, the address-vector quantizer (A-VQ), is proposed which exploits the interblock correlation by encoding a group of blocks together using an address-codebook (AC). The AC is a set of address-codevectors (ACVs), each representing a combination of addresses or indices. Each element of the ACV is an address of an entry in the LBG-codebook, representing a vector-quantized block. The AC consists of an active (addressable) region and an inactive (nonaddressable) region. During encoding the ACVs in the AC are reordered adaptively to bring the most probable ACVs into the active region. When encoding an ACV, the active region is checked, and if such an address combination exists, its index is transmitted to the receiver. Otherwise, the address of each block is transmitted individually. The SNR of the images encoded by the A-VQ method is the same as that of a memoryless vector quantizer, but the bit rate is by a factor of approximately two.
Vector Volume Flow in Arteriovenous Fistulas
DEFF Research Database (Denmark)
Hansen, Peter Møller; Heerwagen, Søren; Pedersen, Mads Møller;
2013-01-01
, but is very challenging due to the angle dependency of the Doppler technique and the anatomy of the fistula. The angle independent vector ultrasound technique Transverse Oscillation provides a new and more intuitive way to measure volume flow in an arteriovenous fistula. In this paper the Transverse...
The Integration Order of Vector Autoregressive Processes
DEFF Research Database (Denmark)
Franchi, Massimo
We show that the order of integration of a vector autoregressive process is equal to the difference between the multiplicity of the unit root in the characteristic equation and the multiplicity of the unit root in the adjoint matrix polynomial. The equivalence with the standard I(1) and I(2...
An Improved Support Vector Machines： NNSVM
Institute of Scientific and Technical Information of China (English)
LIHonglian; WANGChunhua; YUANBaozong
2004-01-01
In this paper we propose an improved support vector machine: NNSVM. It first prunes the training set, reserves or deletes a sample according to whether its nearest neighbor has same class label with itself or not,then trains the new set with standard SVM to obtain a classifier. Experimental results show that NNSVM is better than SVM in speed and accuracy of classiflcation.
Ecology of parasite-vector interactions
Takken, W.; Koenraadt, C.J.M.
2013-01-01
Vector-borne diseases continue to be one of the most important determinants affecting human and animal health. Large numbers of people suffer from diseases like malaria, dengue, filariasis and leishmaniasis, especially in the tropics. Whereas these diseases were eradicated from the temperate climate
[Conflicts and vector-borne diseases
DEFF Research Database (Denmark)
Bygbjerg, Ib Christian
2010-01-01
not available for most diseases. Promising preventive methods, including long-lasting impregnated bed-nets and tents, are available. War has been an impetus for disclosing life-cycles of vector-borne diseases and for control methods; peace, reconciliation and poverty reduction are required to achieve lasting...
NLO vector boson production with light jets
Bern, Z; Dixon, L J; Cordero, F Febres; Forde, D; Gleisberg, T; Hoeche, S; Ita, H; Kosower, D A; Maitre, D; Ozeren, K
2012-01-01
In this contribution we present recent progress in the computation of next-to-leading order (NLO) QCD corrections for the production of an electroweak vector boson in association with jets at hadron colliders. We focus on results obtained using the virtual matrix element library BLACKHAT in conjunction with SHERPA, focusing on results relevant to understanding the background to top production.
Polynomial Vector Fields in One Complex Variable
DEFF Research Database (Denmark)
Branner, Bodil
In recent years Adrien Douady was interested in polynomial vector fields, both in relation to iteration theory and as a topic on their own. This talk is based on his work with Pierrette Sentenac, work of Xavier Buff and Tan Lei, and my own joint work with Kealey Dias....
A Lesson in Vectors "Plain" and Simple
Bradshaw, David M.
2004-01-01
The United States Military Academy (USMA) has a four course core mathematics curriculum that is studied by all students. The third course is MA205, Calculus II; a multivariate calculus course filled with practical applications. During a Problem Solving Lab (PSL), students participated in a hands-on exercise with multiple vector operations,…
High performance computing on vector systems
Roller, Sabine
2008-01-01
Presents the developments in high-performance computing and simulation on modern supercomputer architectures. This book covers trends in hardware and software development in general and specifically the vector-based systems and heterogeneous architectures. It presents innovative fields like coupled multi-physics or multi-scale simulations.
Perturbations of ultralight vector field dark matter
Cembranos, J A R; Jareño, S J Núñez
2016-01-01
We study the dynamics of cosmological perturbations in models of dark matter based on ultralight coherent vector fields. Very much as for scalar field dark matter, we find two different regimes in the evolution: for modes with $k^2\\ll {\\cal H}ma$, we have a particle-like behaviour indistinguishable from cold dark matter, whereas for modes with $k^2\\gg {\\cal H}ma$, we get a wave-like behaviour in which the sound speed is non-vanishing and of order $c_s^2\\simeq k^2/m^2a^2$. This implies that, also in these models, structure formation could be suppressed on small scales. However, unlike the scalar case, the fact that the background evolution contains a non-vanishing homogeneous vector field implies that, in general, the evolution of the three kinds of perturbations (scalar, vector and tensor) can no longer be decoupled at the linear level. More specifically, in the particle regime, the three types of perturbations are actually decoupled, whereas in the wave regime, the three vector field perturbations generate o...
Risk based surveillance for vector borne diseases
DEFF Research Database (Denmark)
Bødker, Rene
of samples and hence early detection of outbreaks. Models for vector borne diseases in Denmark have demonstrated dramatic variation in outbreak risk during the season and between years. The Danish VetMap project aims to make these risk based surveillance estimates available on the veterinarians smart phones...
Angry Birds Mathematics: Parabolas and Vectors
Lamb, John H.
2013-01-01
John Lamb, a professor of mathematics education and a teacher of high school precalculus, describes how he developed a way to use the elements of the game Angry Birds® as a platform to engage his students with the concepts of parabolas and vectors. The game could be categorized as a type of microworld game in which students interact with the…
Angry Birds Mathematics: Parabolas and Vectors
Lamb, John H.
2013-01-01
John Lamb, a professor of mathematics education and a teacher of high school precalculus, describes how he developed a way to use the elements of the game Angry Birds® as a platform to engage his students with the concepts of parabolas and vectors. The game could be categorized as a type of microworld game in which students interact with the…
Bethe vectors for XXX-spin chain
Burdík, Čestmír; Fuksa, Jan; Isaev, Alexei
2014-11-01
The paper deals with algebraic Bethe ansatz for XXX-spin chain. Generators of Yang-Baxter algebra are expressed in basis of free fermions and used to calculate explicit form of Bethe vectors. Their relation to N-component models is used to prove conjecture about their form in general. Some remarks on inhomogeneous XXX-spin chain are included.
Virtual Vector Machine for Bayesian Online Classification
Minka, Thomas P; Yuan,; Qi,
2012-01-01
In a typical online learning scenario, a learner is required to process a large data stream using a small memory buffer. Such a requirement is usually in conflict with a learner's primary pursuit of prediction accuracy. To address this dilemma, we introduce a novel Bayesian online classi cation algorithm, called the Virtual Vector Machine. The virtual vector machine allows you to smoothly trade-off prediction accuracy with memory size. The virtual vector machine summarizes the information contained in the preceding data stream by a Gaussian distribution over the classi cation weights plus a constant number of virtual data points. The virtual data points are designed to add extra non-Gaussian information about the classi cation weights. To maintain the constant number of virtual points, the virtual vector machine adds the current real data point into the virtual point set, merges two most similar virtual points into a new virtual point or deletes a virtual point that is far from the decision boundary. The info...
Generating and measuring nondiffracting vector Bessel beams
CSIR Research Space (South Africa)
Dudley, Angela L
2013-09-01
Full Text Available modulator and an azimuthally varying birefringent plate, known as a q-plate. We extend our control of both the geometric and dynamic phases to perform a polarization and modal decomposition on the vector field. We study both single-charged Bessel beams...
Meromorphic Vector Fields and Circle Packings
DEFF Research Database (Denmark)
Dias, Kealey
to structurally stable vector fields, there is an underlying dynamically defined triangulation of the plane. Circle packings are a means to realize such a given combinatorial structure. About 20 years ago, W. Thurston suggested applying circle packings to obtain approximations to Riemann mappings. This gave rise...
Symmetries of Elko and massive vector fields
Lee, Cheng-Yang
2013-01-01
This thesis studies the symmetries and phenomenologies of the massive vector fields of indefinite spin with both scalar and spin-one degrees of freedom and Elko. The investigation is conducted by using and extending the quantum field theory formalism developed by Wigner and Weinberg. In particular, we explore the possibility that the $W^{\\pm}$ and $Z$ bosons have an additional scalar degree of freedom and show that Elko is a fermionic dark matter candidate. We show that the massive vector fields of indefinite spin are consistent with Poincar\\'{e} symmetry and have physically desirable properties that are absent for their pure spin-one counterpart. Using the new vector fields, the decay of the $W^{\\pm}$ and $Z$ bosons to leptons at tree-level are in agreement with the Standard Model (SM) predictions. For higher order scattering amplitudes, the theory has better convergent behaviour than the intermediate vector boson model and the Fermi theory. Elko has the unusual property that it satisfies the Klein-Gordon bu...
Demonstration of a Vector Velocity Technique
DEFF Research Database (Denmark)
Hansen, Peter Møller; Pedersen, Mads M.; Hansen, Kristoffer L.;
2011-01-01
With conventional Doppler ultrasound it is not possible to estimate direction and velocity of blood flow, when the angle of insonation exceeds 60–70°. Transverse oscillation is an angle independent vector velocity technique which is now implemented on a conventional ultrasound scanner. In this pa...
Generalized Derivative Based Kernelized Learning Vector Quantization
Schleif, Frank-Michael; Villmann, Thomas; Hammer, Barbara; Schneider, Petra; Biehl, Michael; Fyfe, Colin; Tino, Peter; Charles, Darryl; Garcia-Osoro, Cesar; Yin, Hujun
2010-01-01
We derive a novel derivative based version of kernelized Generalized Learning Vector Quantization (KGLVQ) as an effective, easy to interpret, prototype based and kernelized classifier. It is called D-KGLVQ and we provide generalization error bounds, experimental results on real world data, showing t
Optimal Hedging with the Vector Autoregressive Model
L. Gatarek (Lukasz); S.G. Johansen (Soren)
2014-01-01
markdownabstract__Abstract__ We derive the optimal hedging ratios for a portfolio of assets driven by a Cointegrated Vector Autoregressive model with general cointegration rank. Our hedge is optimal in the sense of minimum variance portfolio. We consider a model that allows for the hedges to be
Linearization of germs of hyperbolic vector fields
Bonckaert, P; Naudot, [No Value; Yang, JZ
2003-01-01
We develop a normal form to express asymptotically a conjugacy between a germ of resonant vector field and its linear part. We show that such an asymptotic expression can be written in terms of functions of the Logarithmic Mourtada type. To cite this article: P Bonckaert et al., C. R. Acad. Sci. Par
η-Invariant and Flat Vector Bundles
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
We present an alternate definition of the mod Z component of the AtiyahPatodi-Singer η invariant associated to (not necessary unitary) fiat vector bundles, which identifies explicitly its real and imaginary parts. This is done by combining a deformation of flat connections introduced in a previous paper with the analytic continuation procedure appearing in the original article of Atiyah, Parodi and Singer.
Vector Potential, Electromagnetic Induction and "Physical Meaning"
Giuliani, G.
2010-01-01
A forgotten experiment by Andre Blondel (1914) proves, as held on the basis of theoretical arguments in a previous paper, that the time variation of the magnetic flux is not the cause of the induced emf; the physical agent is instead the vector potential through the term [equation omitted] (when the induced circuit is at rest). The "good…
Anomalous effective lagrangians and vector resonance models
Pallante, E.; Petronzio, R.
1993-01-01
Chiral lagrangians including vector resonances have been shown to saturate the finite part of some of the counterterms needed to regularize ordinary one-loop effective lagrangians of pseudoscalar interactions with external currents. The equivalence between different models has been discussed in the
Teaching Universal Gravitation with Vector Games
Lowry, Matthew
2008-01-01
Like many high school and college physics teachers, I have found playing vector games to be a useful way of illustrating the concepts of inertia, velocity, and acceleration. Like many, I have also had difficulty in trying to get students to understand Newton's law of universal gravitation, specifically the inverse-square law and its application to…
Students' Difficulties with Vector Calculus in Electrodynamics
Bollen, Laurens; van Kampen, Paul; De Cock, Mieke
2015-01-01
Understanding Maxwell's equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven…
Weighted Twin Support Vector Machine with Universum
Directory of Open Access Journals (Sweden)
Shuxia Lu
Full Text Available Universum is a new concept proposed recently, which is defined to be the sample that does not belong to any classes concerned. Support Vector Machine with Universum (..-SVM is a new algorithm, which can exploit Universum samples to improve the classifica ...
Novel cloning vectors for Bacillus thuringiensis.
Baum, J A; Coyle, D M; Gilbert, M P; Jany, C S; Gawron-Burke, C
1990-11-01
Seven replication origins from resident plasmids of Bacillus thuringienis subsp. kurstaki HD263 and HD73 were cloned in Escherichia coli. Three of these replication origins, originating from plasmids of 43, 44, and 60 MDa, were used to construct a set of compatible shuttle vectors that exhibit structural and segregational stability in the Cry- strain B. thuringiensis HD73-26. These shuttle vectors, pEG597, pEG853, and pEG854, were designed with rare restriction sites that permit various adaptations, including the construction of small recombinant plasmids lacking antibiotic resistance genes. The cryIA(c) and cryIIA insecticidal crystal protein genes were inserted into these vectors to demonstrate crystal protein production in B. thuringiensis. Introduction of a cloned cryIA(c) gene from strain HD263 into a B. thuringiensis subsp. aizawai strain exhibiting good insecticidal activity against Spodoptera exigua resulted in a recombinant strain with an improved spectrum of insecticidal activity. Shuttle vectors of this sort should be valuable in future genetic studies of B. thuringiensis as well as in the development of B. thuringiensis strains for use as microbial pesticides.
Creating and decomposing vector Bessel beams
CSIR Research Space (South Africa)
Dudley, Angela L
2013-07-01
Full Text Available Bessel beams, presented at the 58th annual SAIP conference. The paper discusses spatially inhomogeneous polarization states that are referred to as cylindrical vector beams which include radial and azimuthal polarization. Also included... in the presentation is a demonstration on orbitual agular momentum of light and the transformation of Laquerre-Gaussian laser modes. ...
Vector Product and an Integrable Dynamical System
Institute of Scientific and Technical Information of China (English)
Willi-Hans Steeb; Yorick Hardy; Igor Tanski
2011-01-01
We study an autonomous system of first order ordinary differential equations based on the vector product. We show that the system is completely integrable by constructing the first integrals. The connection with Nambu mechanics is established. The extension to higher dimensions is also discussed.
Vector biology prospects in dengue research
Directory of Open Access Journals (Sweden)
Louis Lambrechts
2012-12-01
Full Text Available We argue that using more natural blood feeding methods to study mosquito vector competence for dengue viruses and exploring the effect of viral infection on other mosquito life-history traits that influence vectorial capacity will significantly advance our understanding of dengue epidemiology.
DSm Vector Spaces of Refined Labels
Kandasamy, W B Vasantha
2011-01-01
In this book the authors introduce the notion of DSm vector spaces of refined labels. They also realize the refined labels as a plane and a n-dimensional space. Further, using these refined labels, several algebraic structures are defined. Finally DSm semivector space or refined labels is described. Authors also propose some research problems.
Global traffic and disease vector dispersal.
Tatem, Andrew J; Hay, Simon I; Rogers, David J
2006-04-18
The expansion of global air travel and seaborne trade overcomes geographic barriers to insect disease vectors, enabling them to move great distances in short periods of time. Here we apply a coupled human-environment framework to describe the historical spread of Aedes albopictus, a competent mosquito vector of 22 arboviruses in the laboratory. We contrast this dispersal with the relatively unchanged distribution of Anopheles gambiae and examine possible future movements of this malaria vector. We use a comprehensive database of international ship and aircraft traffic movements, combined with climatic information, to remap the global transportation network in terms of disease vector suitability and accessibility. The expansion of the range of Ae. albopictus proved to be surprisingly predictable using this combination of climate and traffic data. Traffic volumes were more than twice as high on shipping routes running from the historical distribution of Ae. albopictus to ports where it has established in comparison with routes to climatically similar ports where it has yet to invade. In contrast, An. gambiae has rarely spread from Africa, which we suggest is partly due to the low volume of sea traffic from the continent and, until very recently, a European destination for most flights.
Testing for vector autoregressive dynamics under heteroskedasticity
C.M. Hafner (Christian); H. Herwartz
2002-01-01
textabstractIn this paper we introduce a bootstrap procedure to test parameter restrictions in vector autoregressive models which is robust in cases of conditionally heteroskedastic error terms. The adopted wild bootstrap method does not require any parametric specification of the volatility process
Bayesian Vector Autoregressions with Stochastic Volatility
Uhlig, H.F.H.V.S.
1996-01-01
This paper proposes a Bayesian approach to a vector autoregression with stochastic volatility, where the multiplicative evolution of the precision matrix is driven by a multivariate beta variate.Exact updating formulas are given to the nonlinear filtering of the precision matrix.Estimation of the au
MHD thrust vectoring of a rocket engine
Labaune, Julien; Packan, Denis; Tholin, Fabien; Chemartin, Laurent; Stillace, Thierry; Masson, Frederic
2016-09-01
In this work, the possibility to use MagnetoHydroDynamics (MHD) to vectorize the thrust of a solid propellant rocket engine exhaust is investigated. Using a magnetic field for vectoring offers a mass gain and a reusability advantage compared to standard gimbaled, elastomer-joint systems. Analytical and numerical models were used to evaluate the flow deviation with a 1 Tesla magnetic field inside the nozzle. The fluid flow in the resistive MHD approximation is calculated using the KRONOS code from ONERA, coupling the hypersonic CFD platform CEDRE and the electrical code SATURNE from EDF. A critical parameter of these simulations is the electrical conductivity, which was evaluated using a set of equilibrium calculations with 25 species. Two models were used: local thermodynamic equilibrium and frozen flow. In both cases, chlorine captures a large fraction of free electrons, limiting the electrical conductivity to a value inadequate for thrust vectoring applications. However, when using chlorine-free propergols with 1% in mass of alkali, an MHD thrust vectoring of several degrees was obtained.
Efficient Multiplicative Updates for Support Vector Machines
DEFF Research Database (Denmark)
Potluru, Vamsi K.; Plis, Sergie N; Mørup, Morten
2009-01-01
The dual formulation of the support vector machine (SVM) objective function is an instance of a nonnegative quadratic programming problem. We reformulate the SVM objective function as a matrix factorization problem which establishes a connection with the regularized nonnegative matrix factorization...
Lentiviral Vectors and Cystic Fibrosis Gene Therapy
Castellani, Stefano; Conese, Massimo
2010-01-01
Cystic fibrosis (CF) is a chronic autosomic recessive syndrome, caused by mutations in the CF Transmembrane Conductance Regulator (CFTR) gene, a chloride channel expressed on the apical side of the airway epithelial cells. The lack of CFTR activity brings a dysregulated exchange of ions and water through the airway epithelium, one of the main aspects of CF lung disease pathophysiology. Lentiviral (LV) vectors, of the Retroviridae family, show interesting properties for CF gene therapy, since they integrate into the host genome and allow long-lasting gene expression. Proof-of-principle that LV vectors can transduce the airway epithelium and correct the basic electrophysiological defect in CF mice has been given. Initial data also demonstrate that LV vectors can be repeatedly administered to the lung and do not give rise to a gross inflammatory process, although they can elicit a T cell-mediated response to the transgene. Future studies will clarify the efficacy and safety profile of LV vectors in new complex animal models with CF, such as ferrets and pigs. PMID:21994643
$h$-vectors of small matroid complexes
DeLoera, Jesus; Klee, Steven
2011-01-01
Stanley conjectured in 1977 that the $h$-vector of a matroid simplicial complex is a pure $O$-sequence. We give simple constructive proofs that the conjecture is true for matroids of rank less than or equal to 3, and corank 2. We used computers to verify that Stanley's conjecture holds for all matroids on at most nine elements.
A review of learning vector quantization classifiers
Nova, David
2015-01-01
In this work we present a review of the state of the art of Learning Vector Quantization (LVQ) classifiers. A taxonomy is proposed which integrates the most relevant LVQ approaches to date. The main concepts associated with modern LVQ approaches are defined. A comparison is made among eleven LVQ classifiers using one real-world and two artificial datasets.
Isotropy theorem for cosmological vector fields
Cembranos, J A R; Maroto, A L; Jareño, S J Núñez
2012-01-01
We consider homogeneous abelian vector fields in an expanding universe. We find a mechanical analogy in which the system behaves as a particle moving in three dimensions under the action of a central potential. In the case of bounded and rapid evolution compared to the rate of expansion, we show by making use of the virial theorem that for arbitrary potential and polarization pattern, the average energy-momentum tensor is always diagonal and isotropic despite the intrinsic anisotropic evolution of the vector field. For simple power-law potentials of the form V=\\lambda (A^\\mu A_\\mu)^n, the average equation of state is found to be w=(n-1)/(n+1). This implies that vector coherent oscillations could act as natural dark matter or dark energy candidates. Finally, we show that under very general conditions, the average energy-momentum tensor of a rapidly evolving bounded vector field in any background geometry is always isotropic and has the perfect fluid form for any locally inertial observer.
Malaria vector control: current and future strategies
Takken, W.; Knols, B.G.J.
2009-01-01
The recently announced call for malaria eradication represents a new page in the history of this disease. This has been triggered by remarkable reductions in malaria resulting from combined application of effective drugs and vector control. However, this strategy is threatened by development of inse
Multipole vector solitons in nonlocal nonlinear media.
Kartashov, Yaroslav V; Torner, Lluis; Vysloukh, Victor A; Mihalache, Dumitru
2006-05-15
We show that multipole solitons can be made stable via vectorial coupling in bulk nonlocal nonlinear media. Such vector solitons are composed of mutually incoherent nodeless and multipole components jointly inducing a nonlinear refractive index profile. We found that stabilization of the otherwise highly unstable multipoles occurs below certain maximum energy flow. Such a threshold is determined by the nonlocality degree.
Population structure of an island malaria vector.
Foley, D H; Torres, E P
2006-12-01
The impact of islands on the population structure of Anopheles flavirostris (Ludlow) (Diptera: Culicidae), the primary malaria vector in the Philippines, was assessed. A phylogenetic analysis of 16 cytochrome oxidase subunit 1 (CO1) haplotypes revealed three clades: one basal clade containing genetically disparate haplotypes from Mindanao, and two derived clades, one of which was largely confined to the largest island, Luzon, and one that was widespread except for Luzon. For the Luzon clade, nested clade analysis revealed an isolation-by-distance effect, and a mismatch distribution analysis diagnosed a recent demographic expansion (sum of squared deviation, SDD = 0.0093, P= 0.075), which mirrors demographic attributes found in mainland primary malaria vectors and could inflate estimates of gene flow from F(ST). For the widespread clade, evidence of range expansion and past fragmentation and/or long distance colonization from the Visayas or Mindanao to Palawan is suggested. A south-to-north range expansion of An. flavirostris is suggested; estimates of coalescence for the Luzon clade was 214 000 years ago (ya) (95% confidence interval 35 600-298 000 ya), i.e. late Pleistocene. Present day rather than Pleistocene island association and some, but not all, sea barriers appeared to be important for An. flavirostris population structure. Our results suggest that endemic island malaria vector species need to be considered before any generalizations are made about the population structure of primary and secondary vectors.
Oracle Inequalities for High Dimensional Vector Autoregressions
DEFF Research Database (Denmark)
Callot, Laurent; Kock, Anders Bredahl
This paper establishes non-asymptotic oracle inequalities for the prediction error and estimation accuracy of the LASSO in stationary vector autoregressive models. These inequalities are used to establish consistency of the LASSO even when the number of parameters is of a much larger order...
Ecology of parasite-vector interactions
Takken, W.; Koenraadt, C.J.M.
2013-01-01
Vector-borne diseases continue to be one of the most important determinants affecting human and animal health. Large numbers of people suffer from diseases like malaria, dengue, filariasis and leishmaniasis, especially in the tropics. Whereas these diseases were eradicated from the temperate climate
The Higher Spin/Vector Model Duality
Giombi, Simone; Yin, Xi
2012-01-01
This paper is mainly a review of the dualities between Vasiliev's higher spin gauge theories in AdS4 and three dimensional large N vector models, with focus on the holographic calculation of correlation functions of higher spin currents. We also present some new results in the computation of parity odd structures in the three point functions in parity violating Vasiliev theories.