Vector Configuration Research Articles

Applications for Asynchronous Multi-agent Teams in Nonlinear Applied Spatial Econometrics

Asynchronous multi-agent systems have been widely used to optimize complex combinatorial problems. Their main strength lies in their ability to combine different heuristic algorithms and thus arrive at comparatively better solutions then their constituting algorithms on their own. A further strength is their flexibility in interlinked problems. This ability especially can be utilized in the semi-parametric modeling of applied spatial econometric problems. Semi-parametric modeling is required, if one wants to estimate nonlinear relationships between the dependent and the independent variables. The special case of spatial semi-parametric modeling requires determining the best configuration of independent variable vectors, number of spline-knots and their positions. Determining these poses an interlinked problem where the optimization of one part depends heavily upon the optimization of the others; therefore an asynchronous multi-agent team is used, to solve them simultaneously. This paper demonstrates that the proposed method can be used to model nonlinearity and furthermore it provides applied examples for real-life data sets.

A Lost Counterexample and a Problem on Illuminated Polytopes

Daniel A. Marcus claimed in a “Note added in proof” to his 1984 paper on positively k-spanning vector configurations that some minimal positively k-spanning vector configurations in m-dimensional space have more than 2km elements, but the example he found (for k = 2 and m = 12) seems to be lost.We produce such an example by applying Gale duality, a linear algebra technique developed by Micha Perles in the sixties, to a result on illuminated polytopes by Peter Mani from 1974. Our example has exactly the parameters claimed by Marcus.Conversely, we show how results on positively k-spanning vector configurations, again via Gale duality, can be used to solve a problem by Mani on nonsimplicial illuminated polytopes.

Correction of SCID-X1 Using an EnhancerlessVavPromoter

The efficacy of gene therapy for the treatment of inherited immunodeficiency has been highlighted in recent clinical trials, although in some cases complicated by insertional mutagenesis and silencing of vector genomes through methylation. To minimize these effects, we have evaluated the use of regulatory elements that confer reliability of gene expression, but also lack potent indiscriminate enhancer activity. The Vav1 proximal promoter is particularly attractive in this regard and may be useful in situations where high-level or complex regulation of gene expression is not necessary. X-linked severe combined immunodeficiency (SCID-X1) is a good candidate for such an approach, particularly as there may be additional disease-related intrinsic risks of leukemogenesis, and where safety is therefore a paramount concern. We have tested whether lentiviral vectors expressing the common cytokine receptor gamma chain under the control of the proximal Vav1 gene promoter are effective for correction of signaling defects and the disease phenotype. Despite low-level gene expression, we observed near-complete restoration of cytokine-mediated STAT5 phosphorylation in a model cell line. Furthermore, at low vector copy number, highly effective T- and B-lymphocyte reconstitution was achieved in vivo in a murine model of SCID-X1, in both primary and secondary graft recipients. This vector configuration deserves further evaluation and consideration for future clinical trials.

Evaluation of transduction efficiency in macrophage colony-stimulating factor differentiated human macrophages using HIV-1 based lentiviral vectors.

BackgroundMonocyte-derived macrophages contribute to atherosclerotic plaque formation. Therefore, manipulating macrophage function could have significant therapeutic value. The objective of this study was to determine transduction efficiency of two HIV-based lentiviral vector configurations as delivery systems for the transduction of primary human blood monocyte-derived macrophages.ResultsHuman blood monocytes were transduced using two VSV-G pseudotyped HIV-1 based lentiviral vectors containing EGFP expression driven by either native HIV-LTR (VRX494) or EF1α promoters (VRX1090). Lentiviral vectors were added to cultured macrophages at different times and multiplicities of infection (MOI). Transduction efficiency was assessed using fluorescence microscopy and flow cytometry. Macrophages transduced between 2 and 120 hours after culturing showed the highest transduction efficiency at 2-hours transduction time. Subsequently, cells were transduced 2 hours after culturing at various vector concentrations (MOIs of 5, 10, 25 and 50) to determine the amount of lentiviral vector particles required to maximally transduce human monocyte-derived macrophages. On day 7, all transduced cultures showed EGFP-positive cells by microscopy. Flow cytometric analysis showed with all MOIs a peak shift corresponding to the presence of EGFP-positive cells. For VRX494, transduction efficiency was maximal at an MOI of 25 to 50 and ranged between 58 and 67%. For VRX1090, transduction efficiency was maximal at an MOI of 10 and ranged between 80 and 90%. Thus, transductions performed with VRX1090 showed a higher number of EGFP-positive cells than VRX494.ConclusionsThis report shows that VSV-G pseudotyped HIV-based lentiviral vectors can efficiently transduce human blood monocyte-derived macrophages early during differentiation using low particle numbers that do not interfere with differentiation of monocytes into macrophages.

On a spherical code in the space of spherical harmonics

We propose a new method for the construction of new “nice” configurations of vectors on the unit sphere S d with the use of spaces of spherical harmonics.

The β-Interferon Scaffold Attachment Region Confers High-Level Transgene Expression and Avoids Extinction by Epigenetic Modifications of Integrated Provirus in Adipose Tissue-Derived Human Mesenchymal Stem Cells

Because of their abundance and ease of isolation, multilineage differentiation, and paracrine and immunoregulatory capabilities, genetically engineered adipose tissue-derived mesenchymal stem cells (ASCs) might combine cell- and gene therapy-based strategies for efficacious tissue repair/regeneration. In this report, we aimed to analyze and influence the long-term dynamics of transgene expression in ASCs transduced with different gammaretroviral vector configurations incorporating the human β-interferon scaffold attachment region (IFN-SAR) and/or chicken 5'HS4 β-globin insulator sequences. In our undifferentiated ASC culture model, naked retroviral vectors experienced EGFP transgene extinction correlating with increases in both H3 histone deacetylation and CpG dinucleotide methylation within the 5' long terminal repeat-primer-binding site proviral region. Retroviral configurations incorporating the referred boundary elements alone or combined were able to prevent the development of the above epigenetic events and to reduce transgene extinction to different degrees. Particularly, the IFN-SAR sustained the highest levels of H3 histone acetylation and transgene expression throughout the study. Analogously, ASCs differentiating to adipocytes or osteocytes experienced a gradual decline of EGFP expression using naked retroviral vectors. In contrast, only retroviral configurations including the IFN-SAR alone were able to overcome the epigenetic pressure, yielding high-level, uniform transgene expression throughout both lineage differentiation processes. Thus, embedding the IFN-SAR in retroviral vectors should have positive implications in gene repair strategies using ASCs.

Polyethylenimine Based Magnetic Iron-Oxide Vector: The Effect of Vector Component Assembly on Cellular Entry Mechanism, Intracellular Localization, and Cellular Viability

The order of assembly of a magnetic nanoparticle (MNP) vector comprised of the same components (MNP, PEI, and plasmid DNA) on entry mechanism, intracellular localization, and viability of BHK21 cells was investigated. Cellular uptake measurements under four different uptake inhibiting conditions, such as low temperature, depleted cellular ATP, nystatin treatment, and hypertonic environment, show that the cellular entry mechanism of the MNP vector was mediated via clathrin endocytosis. Despite different vector component assembly, all MNP vectors were taken up by the cells through the same mechanism. Labeling and intracellular tracking of the MNP vectors using epi-fluorescence and confocal laser scanning microscopy showed localization of MNP vector within the lysosomes when DNA was assembled on the outer layer of vector. Conversely, when PEI was on the surface of the vector, such that it enclosed both magnetic nanoparticles and the DNA, vector localization in the cell nucleus was observed. The microscopy results demonstrated that the configuration of the MNP vectors dictate the vector's final intracellular target location, and thus the efficiency of transfection. The cellular viability assessment using three different assays further showed that the cellular viability of MNP vector was dose-dependent and varied with the assembly of vector component. All viability assays found negligible toxicity when DNA was on the outer layer of MNP vector except at the highest vector loading. In contrast, attachment of PEI on MNP vector surface induced a significant decrease in cellular viability, due to the ability of PEI on the MNP vector to rupture the lysosomal vesicles.

Bounds for solid angles of lattices of rank three

We find sharp absolute constants C 1 and C 2 with the following property: every well-rounded lattice of rank 3 in a Euclidean space has a minimal basis so that the solid angle spanned by these basis vectors lies in the interval [ C 1 , C 2 ] . In fact, we show that these absolute bounds hold for a larger class of lattices than just well-rounded, and the upper bound holds for all. We state a technical condition on the lattice that may prevent it from satisfying the absolute lower bound on the solid angle, in which case we derive a lower bound in terms of the ratios of successive minima of the lattice. We use this result to show that among all spherical triangles on the unit sphere in R N with vertices on the minimal vectors of a lattice, the smallest possible area is achieved by a configuration of minimal vectors of the (normalized) face centered cubic lattice in R 3 . Such spherical configurations come up in connection with the kissing number problem.

The analysis of a piezoelectric bimorph beam with two input base motions for power harvesting

The exploitation of usable power from vibration environments shows potential benefit for recharging batteries and powering wireless transmission. In this paper, we present a novel technique for simulating the electromechanical cantilevered piezoelectric bimorph beam system with two input base transverse and longitudinal motions for predicting power harvesting. The piezoelectric bimorph beam with tip mass was modelled using the Euler-Bernoulli beam assumptions. The strain fields from transverse bending and longitudinal forms can affect the physical behaviour of the polarity and electric field in terms of the series and parallel connections of the piezoelectric bimorph, in such way that each connection has two vector configurations of X-poling and Y-poling due to input base motions. This situation must be correctly identified to form the piezoelectric couplings. The piezoelectric couplings can create the electrical force and moment of each piezoelectric layer in the mechanical domain. At this point, we introduce a new method of modelling the piezoelectric bimorph beam under two input base-motions using coupling superposition of the elastic-polarity field for predicting power harvesting. The constitutive dynamic equations were derived using the weak form from the Hamiltonian theorem, with Laplace transforms being used to obtain the multi-mode frequency response functions (FRFs) relating the input mechanical vibrations with the output dynamic displacement, velocity and power harvesting. The power harvesting predictions under parallel connection at frequencies close to the fundamental bending frequency demonstrate a possibility of being able to produce around 0.4 mW per unit input base transverse acceleration of 3 m/s2. Furthermore, it is shown that varying the load resistance from 20 kΩ to 200 kΩ affects the amplitude of power harvesting as well as resulting in a shift of the first natural frequency from 76 Hz to 79 Hz.

A system of metrically invariant relations between the moduli squares of reciprocal-lattice vectors in one-, two- and three-dimensional space

Given the background of trial-and-error methods employed in recent automatic powder pattern indexing, an alternative route is suggested based on a generalization of the original Runge–de Wolff approach. For this purpose, a system of five metrically invariant relations between the squared moduli (Qvalues) of reciprocal-lattice vectors is developed that encompasses the earlier special relations. The five invariant relations correspond to a line, a zone, a bizone, a cone and a pencil configuration of reciprocal-lattice vectors. In particular, the zone configuration relates four vectors being arbitrarily distributed in a plane and as such allows one to identify among a set of measuredQvalues all quadruples that define reciprocal-lattice planes intersecting in space.

The watershed of Modernity: translation and the epistemological revolution

From Modernity on, there has been continuity for the ‘West’ and interruption for non‐European cultures, histories and languages, for which indeed there is supposed to be only discontinuity with their own antiquity. Their own past counts as ‘premodern’ or ‘traditional’, and thus as belated compared with universalised Modernity. This is so because Modernity itself is normative, and it is normative because it was universalised. The norm of Modernity and the dignity of the modern ‘political’ has been spread through western idioms: through the western normativity of the political, such concepts as democracy, revolution, state, republic and the like will have their patterns in ‘Europe’ and in the ‘West’, while all other political concepts and terms, when contributed to a world dictionary of political terms, will denote merely exceptions. Modernity has been one of the great splits or disjunctions that froze some norms in history, making them become patterns: from that time on, western modernity (first western, then ‘western’ and finally ‘universal’…) has constructed an unbroken genealogical origin for its own concepts and episteme as ‘universal’, and has proposed/imposed them to the planet. The patterns of selection, exception and exclusion of Modernity, which posit the subject as an ‘autonomous’ figure mirrored and complementary of (state) sovereignty – while referring it to the hegemonically dominant model – have not altogether disappeared today. They are merging and mutating into, and coextensive with, configurations of multiple power vectors within non‐transparent networks of blurred and crossed hierarchies with novel, and maybe more volatile, forms of production, of integration and of institution, where again, although in a completely new way, collective action, the sharing and federation of knowledge transcend individual subjectivity while reaching out to both old and new forms of association.

Assembly of Polyethylenimine-Based Magnetic Iron Oxide Vectors: Insights into Gene Delivery

The use of a nonviral magnetic vector, comprised of magnetic iron oxide nanoparticles (MNP), polyethylenimine (PEI), and plasmid DNA, for transfection of BHK21 cells under a magnetic field is presented. Four different vector configurations were studied by systematically varying the mixing order of MNP, PEI, and DNA. The assembly of the vector has significant effects on its vector size, surface charge, cellular uptake, and level of gene expression. Mixing MNP with PEI first improved MNP stability, giving a narrow aggregate size distribution and positive surface charge at physiological pH, which in turn facilitated DNA binding onto MNP. The presence of serum in culture media improves vector dispersion and alters the surface charge of all vectors to negative charge, indicating serum protein adsorption. Cellular uptake was greater for larger vectors than the smaller vectors due to enhanced gravitational and magnetic aided sedimentation onto the cells. High MNP uptake by the cells, however, does not inevitably lead to increase gene expression efficiency. It can be shown that besides vector uptake, gene expression is affected by extracellular factors such as premature DNA release from MNP and DNA degradation by serum as well as intracellular factors such as vector lysosomal degradation, inability of DNA to detach from MNP, and cytotoxic effects of MNP at high uptake. Some of these extra- and intracellular properties are shown to be mediated by the presence of PEI.

Gale duality bounds for roots of polynomials with nonnegative coefficients

We bound the location of roots of polynomials that have nonnegative coefficients with respect to a fixed but arbitrary basis of the vector space of polynomials of degree at most d. For this, we interpret the basis polynomials as vector fields in the real plane, and at each point in the plane analyze the combinatorics of the Gale dual vector configuration. This approach permits us to incorporate arbitrary linear equations and inequalities among the coefficients in a unified manner to obtain more precise bounds on the location of roots. We apply our technique to bound the location of roots of Ehrhart and chromatic polynomials. Finally, we give an explanation for the clustering seen in plots of roots of random polynomials.

Testing for the Supremacy of a Multinomial Cell Probability

Tests for the supremacy of a multinomial cell probability are developed. The tested null hypothesis states that a particular cell of interest is not more probable than all others. Rejection of this null leads to the conclusion that the cell of interest has a strictly greater probability than all other cells. The null hypothesis constrains the multinomial probability vector to a nonconvex region that is a union of closed convex cones. The likelihood ratio test for this problem is derived and shown to be equivalent to an intersection–union test. The least favorable configuration of the multinomial probability vector in the null parameter space is derived, and the limiting null distribution of the test statistic that is stochastically greatest is shown to be a mixture of point mass at zero and a chi-square distribution with a single degree of freedom. Asymptotic and valid finite-sample testing procedures are proposed and examined via a simulation study and the analysis of two datasets. The proposed procedures are extended to test whether the cell with the largest observed frequency is uniquely most probable. An equivalence between a likelihood ratio test for this problem and a union–intersection test is demonstrated.

Vortices in p-Wave Superfluids of Trapped Fermionic Atom Gases

In order to help detecting superfluidity, we theoretically investigate p -wave pairing superfluids in neutral Fermion atom gases confined by a three dimensional (3D) harmonic potential. The Ginzburg–Landau framework, which is generic for p -wave superfluids, is used to describe the order parameter spatial structure, or texture characterized by the l -vector both at rest and under rotation. The l -vector configuration is strongly contrained by the boundary condition due to a trap. It is found that the ground state textures exhibit spontaneous supercurrent at rest both cigar and pancake shape traps. The current direction depends on the trapping shape. Under rotation a pair of half-quantum vortex with half-winding number enters a system and is stabilized for both trap geometries. We give detailed explanation for their 3D structure. The deformations of the condensate shape are seen with increasing the rotation speed, which is tightly connected with the underlying vortex formation where the condensates are depressed in the vortex core.

Spatial aliasing and distortion of energy distribution in the wave vector domain under multi-spacecraft measurements

Abstract. Aliasing is a general problem in the analysis of any measurements that make sampling at discrete points. Sampling in the spatial domain results in a periodic pattern of spectra in the wave vector domain. This effect is called spatial aliasing, and it is of particular importance for multi-spacecraft measurements in space. We first present the theoretical background of aliasing problems in the frequency domain and generalize it to the wave vector domain, and then present model calculations of spatial aliasing. The model calculations are performed for various configurations of the reciprocal vectors and energy spectra or distribution that are placed at different positions in the wave vector domain, and exhibit two effects on aliasing. One is weak aliasing, in which the true spectrum is distorted because of non-uniform aliasing contributions in the Brillouin zone. It is demonstrated that the energy distribution becomes elongated in the shortest reciprocal lattice vector direction in the wave vector domain. The other effect is strong aliasing, in which aliases have a significant contribution in the Brillouin zone and the energy distribution shows a false peak. These results give a caveat in multi-spacecraft data analysis in that spectral anisotropy obtained by a measurement has in general two origins: (1) natural and physical origins like anisotropy imposed by a mean magnetic field or a flow direction; and (2) aliasing effects that are imposed by the configuration of the measurement array (or the set of reciprocal vectors). This manuscript also discusses a possible method to estimate aliasing contributions in the Brillouin zone based on the measured spectrum and to correct the spectra for aliasing.

Configuration representation and reconfiguration optimization for the reconfigurable robots with independent manipulation

Single module of the reconfigurable robots with independent manipulation can perform the actions of locomotion and manipulation. In conformity with the request for achieving autonomous operation in the unstructurized environment instead of fixed operation in the structurized environment, these robots are applied in the complicated and dangerous environment. The existing researches on the configuration theory focus on the reconfigurable robots with limited locomotion and the ones with independent locomotion, not being applicable to the reconfigurable robots with independent manipulation. The vector configuration is put forward, the research content of which contains the topology and locomotion direction of configuration, the posture and orientation and connection relation between modules. Module state vector and configuration state matrix are proposed for representation methodology for the swarm configuration of these reconfigurable robots, which supports transformation operation to represent and trigger behavior motion of the module and reconfiguration between configurations. Optimization algorithm of assembly reconfiguration applying workload as the optimization target is presented, as well as optimization algorithm of transformation reconfiguration applying the integration of posture orientation workload and connection workload. The result of optimization is the relation of state transformation between the initial configuration and the object one as the basic of reconfiguration plan and control.

Comparing Treatment and Control Groups on Multiple Outcomes

This study considers the problem of testing the difference between treatment and control groups on m ≥ 2 measures when it is assumed a priori that the treatment group will perform better than the control group on all measures. Two procedures are investigated that do not rest on the assumptions of covariance homogeneity or multivariate normality: a likelihood ratio test based on a bootstrap critical value and a composite step-down procedure based on trimmed means. Type I error rates of both procedures are insensitive to assumption violations. Procedures that test a directional alternative hypothesis can be substantially more powerful than a procedure that tests a nondirectional hypothesis for certain configurations of the population mean vectors. The differences in average power of the investigated procedures are a function of the configuration of the population means, the magnitude of correlation among the outcome measures, and the shape of the population distribution.

Effect of theα−γPhase Transition on the Stability of Dislocation Loops in bcc Iron

Body-centered-cubic iron develops an elastic instability, driven by spin fluctuations, near the alpha-gamma phase transition temperature T(c) = 912 degrees C that is associated with the dramatic reduction of the shear stiffness constant c' (c(11)-c(12))/2 near T(c). This reduction of c' has a profound effect on the temperature dependence of the anisotropic elastic self-energies of dislocations in iron. It also affects the relative stability of the a[100] and a/2[111] prismatic edge dislocation loops formed during irradiation. The difference between the anisotropic elastic free energies provides the fundamental explanation for the observed dominant occurrence of the a[100], as opposed to the a/2[111], Burgers vector configurations of prismatic dislocation loops in iron and iron-based alloys at high temperatures.

Self-inactivating Gammaretroviral Vectors for Gene Therapy of X-linked Severe Combined Immunodeficiency

Gene therapy for X-linked severe combined immunodeficiency (SCID-X1) has proven highly effective for long-term restoration of immunity in human subjects. However, the development of lymphoproliferative complications due to dysregulated proto-oncogene expression has underlined the necessity for developing safer vector systems. To reduce the potential for insertional mutagenesis, we have evaluated the efficacy of self-inactivating (SIN) gammaretroviral vectors in cellular and in vivo models of SCID-X1. Vectors incorporating an internal human elongation factor-1alpha regulatory element were capable of fully restoring the lymphoid differentiation potential of gammac-deficient lineage negative cells. Multilineage lymphoid reconstitution of a murine model was achieved at a similar level to that achieved by a conventional long-terminal repeat (LTR)-regulated vector used in previous clinical trials. Functional proliferative responses to mitogenic stimuli were also restored, and serum immunoglobulin levels were normalized. The reduced mutagenic potential conferred by SIN vector configurations and alternative non-LTR-based regulatory elements, together with proven efficacy in correction of cellular defects provides an important platform for development of the next phase of clinical trials for SCID-X1.