Sides Of Triangle Research Articles

Trapping Douglas-fir beetle (Dendroctonus pseudotsugae) with pheromone baited multiple-funnel traps does not reduce Douglas-fir (Pseudotsuga menziesii) mortality

Abstract Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (DFB) causes considerable mortality to Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in western North American forests. We evaluated the use of semiochemical-baited multiple-funnel traps for the protection of small, high-value stands of trees, such as those occurring in campgrounds, rest areas, and small parks when Douglas-fir mortality caused by populations of DFB were at levels of concern to land managers. At two sites in western Montana in 2004, three treated plots were surrounded by three trapping stations arranged in an equilateral triangle (200 m per triangle side). Similar, untreated plots were used for comparison. More than 2 million DFB were trapped and removed from treated plots during 2004, but this trapping did not protect Douglas-fir at either site. Conversely, the ratio of infested to living trees increased substantially due to trapping at one of the sites. Placing semiochemical lures adjacent to stands of susceptible trees...

Self-organization and phase structure of ternary lipid membranes: A spin label EPR study

The phase structure of membranes formed by ternary lipid mixtures, palmitoyl sphingomyelin (PSM)/palmitoyl oleoyl phosphatidylcholine (POPC)/Cholesterol (Chol), the composition of which simulates that of cell membranes, was studied by EPR using spin-labeled phospholipids. It is shown that, in the two-component POPC/Chol membranes and ternary membranes with a low (less than 24%) fraction of PSM, no phase boundaries are observed and the transition from the liquid disordered (ld) phase to the liquid ordered (lo) phase occurs continuously. In contrast, two-component EPR spectra and tie lines are detected in the other two-component systems, PSM/POPC and PSM/Chol, as well as in the ternary systems with a low content of Chol or POPC, respectively. These features are indicative of the coexistence of the gel phase (Lβ) and two liquid phases, ld or lo, respectively. The tie lines are approximately parallel to the Gibbs triangle sides Chol = 0 and POPC = 0, respectively. In the central part of the Gibbs triangle, where a sufficiently fast rotational diffusion of the spin labels indicates the membrane liquid state, we also observed two-component EPR spectra with quite different magnetic anisotropy and tie lines, indicating the coexistence of ld and lo phases. The boundaries are found for all the two-phase coexistence regions. The localization of the three-phase (Lβ, ld, and lo) coexistence region between the two-phase regions (Lβ-ld, Lβ-lo, and ld-lo) was proposed on the basis of an EPR-line shape analysis.

Going the distance: spatial scale of athletic experience affects the accuracy of path integration

Evidence suggests that athletically trained individuals are more accurate than untrained individuals in updating their spatial position through idiothetic cues. We assessed whether training at different spatial scales affects the accuracy of path integration. Groups of rugby players (large-scale training) and martial artists (small-scale training) participated in a triangle-completion task: they were led (blindfolded) along two sides of a right-angled triangle and were required to complete the hypotenuse by returning to the origin. The groups did not differ in their assessment of the distance to the origin, but rugby players were more accurate than martial artists in assessing the correct angle to turn (heading), and landed significantly closer to the origin. These data support evidence that distance and heading components can be dissociated. Furthermore, they suggest that the spatial scale at which an individual is trained may affect the accuracy of one component of path integration but not the other.

On the torsion of a prism with non-equilateral triangular cross-section

The exact solution of Saint–Venant’s problem of torsion of a prism with triangular cross-section is extended from the case when the latter is equilateral to a two-parameter family including isosceles and irregular triangles, but not covering all such shapes. The solution is based on a stress function which vanishes at sides of an arbitrary irregular triangle, whose shape is specified by three parameters. The condition that the stress functions satisfies the Poisson equation imposes one constraint on the three parameters, leading only two free. This covers all equilateral triangles, to which the well known Saint–Venant’s solution applies; it also covers a two-parameter family of isosceles and irregular triangles, corresponding to a generalization of Saint–Venant’s results. These include the stresses in the cross-section and torsional stiffness of the bar.

Generation of spline approximations to parametric tessellations

In geometrical modeling, one is often provided a description of a surface that is defined in terms of a triangulation, which is supported by a discrete number of nodes in space. These faceted surface representations are defined to be C-0 continuous, and therefore in general have slope and curvature discontinuities at the triangle sides, unless the tessellation is planar. Unfortunately, analytical and computational methods often require a surface description that has well-defined and smoothly varying gradients and curvatures; in general spline surfaces possess such properties. Described herein is a process for generating a cubic spline surface that approximates, to within a user-specified tolerance, a given tessellated surface that may be non-convex or multiply connected. The method combines a local least-squares technique for specifying knot properties as well as an adaptation technique for selecting the necessary knot spacings. This new technique is first described along a curve for illustrative purposes. It is then expanded to the case of the general surface. A reparameterization technique that is required for surfaces with non-smooth parameterizations is described next. Computed results for two configurations are then shown.

On the approximation of derivatives of the interpolation Hermite polynomial on a triangle

Bounds on the deviation of the directional derivatives of the Hermite polynomial in the directions of a triangle sides are obtained; it is proved that these bounds are sharp. As a consequence, bounds on the deviations of the partial derivatives up to the third order inclusive are obtained.

Short-term monitoring of benzene air concentration in an urban area: a preliminary study of application of Kruskal-Wallis non-parametric test to assess pollutant impact on global environment and indoor

In step with the need to develop statistical procedures to manage small-size environmental samples, in this work we have used concentration values of benzene (C6H6), concurrently detected by seven outdoor and indoor monitoring stations over 12 000 minutes, in order to assess the representativeness of collected data and the impact of the pollutant on indoor environment. Clearly, the former issue is strictly connected to sampling-site geometry, which proves critical to correctly retrieving information from analysis of pollutants of sanitary interest. Therefore, according to current criteria for network-planning, single stations have been interpreted as nodes of a set of adjoining triangles; then, a) node pairs have been taken into account in order to estimate pollutant stationarity on triangle sides, as well as b) node triplets, to statistically associate data from air-monitoring with the corresponding territory area, and c) node sextuplets, to assess the impact probability of the outdoor pollutant on indoor environment for each area. Distributions from the various node combinations are all non-Gaussian, in the consequently, Kruskal-Wallis (KW) non-parametric statistics has been exploited to test variability on continuous density function from each pair, triplet and sextuplet. Results from the above-mentioned statistical analysis have shown randomness of site selection, which has not allowed a reliable generalization of monitoring data to the entire selected territory, except for a single "forced" case (70%); most important, they suggest a possible procedure to optimize network design.

ТОПОЛОГИЧЕСКАЯ ТРАНСФОРМАЦИЯ ФАЗОВОЙ ДИАГРАММЫ ТРОЙНОЙ СИСТЕМЫ ФОРМИАТ КАЛИЯ - ВОДА - Н.БУТОКСИЭТАНОЛ

Phase equilibria and critical phenomena in the ternary system potas­ sium formate - water - n.butoxyethanol, where a constituent binary liquid system is characterized by phase separation with a closed delamination region, were studied by means of the visual-polythermal method within 25-170°C. The temperature dependences of the com­ positions of the mixtures corresponding to the critical solubility points in the delamination region were determined. The distribution coeffi­ cients of n.butoxyethanol between the aqueous and organic phases of the monotectic equilibrium were calculated for seven temperatures. It is established that the monotectic state in the ternary system is formed as a result of crossing of the line of saturated salt solutions and the binodal curve on the potassium formate - n.butoxyethanol side of the composition triangle at 167.0°C. It is shown that the effect of salting-out of n.butoxyethanol from its aqueous solutions by potas­ sium formate increases with an increase of temperature. The con­structed isotherms of phase states of the system have confirmed our the generalized scheme of topological transformation of the phase diagrams of ternary systems salt - binary solvent with salting-out.

Boundary Element Discretization in Realistic Volume Conductor Modeling in Fetal Magnetoencephalography

Event Abstract Back to Event Boundary Element Discretization in Realistic Volume Conductor Modeling in Fetal Magnetoencephalography Jens Haueisen1*, Roland Eichardt2, Uwe Schneider3 and Ekkehard Schleussner3 1 Technical University Ilmenau, Germany 2 University Hospital Jena, Germany 3 Friedrich Schiller University Jena, University Hospital, Dept. of Obstetrics,, Germany Source reconstruction in fetal Magnetoencephalography (fMEG) has a high potential to become a valuable tool for both basic and clinical research in developmental neurology. However, volume conductor modeling, which is an important prerequisite for source reconstruction, has not been sufficiently addressed so far. In this paper, we investigate the influence of the boundary element discretization on the simulated fMEG. We construct realistic volume conductor models based on 3D ultrasound images. Two different models are considered: a three compartment model including the fetal head, the vernix caseosa, and the maternal abdomen and a three compartment model including the entire fetus, the vernix caseosa, and the maternal abdomen. The boundary element discretization is varied between 20 mm and 12 mm triangle side length for the maternal abdomen, between 7 mm and 2 mm for the vernix caseosa, and between 7 mm and 2 mm for the fetus or the fetal head. The computed magnetic fields caused by dipolar sources positioned in the different models with different discretizations are compared with the help of the magnitude factor and the correlation coefficient. In line with our earlier investigation we find high differences in the computed amplitudes (minimum MAG of 0.47) between the two models for all BEM discretizations, while at the same time the correlation coefficients are above 0.95. This indicates that the entire fetus needs to be considered in the modeling approach. Comparing the different BEM discretizations, we obtain that the largest difference between the coarsest model (20, 7, 7 mm) and the finest model (12, 2, 2 mm) is 26 % in magnitude and the correlation is 0.97. Magnitude differences of less than 6 % and correlation coefficients higher than 0.99 are obtained for a BEM discretization of 16 mm for the abdomen, 5 mm for the vernix caseosa and the fetus. Our simulations provide a first guideline for the construction of boundary element models in fMEG source reconstruction procedures. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Oral Presentation Topic: Fetal and neonatal biomagnetism Citation: Haueisen J, Eichardt R, Schneider U and Schleussner E (2010). Boundary Element Discretization in Realistic Volume Conductor Modeling in Fetal Magnetoencephalography. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00092 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Mar 2010; Published Online: 23 Mar 2010. * Correspondence: Jens Haueisen, Technical University Ilmenau, Ilmenau, Germany, jens.haueisen@tu-ilmenau.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jens Haueisen Roland Eichardt Uwe Schneider Ekkehard Schleussner Google Jens Haueisen Roland Eichardt Uwe Schneider Ekkehard Schleussner Google Scholar Jens Haueisen Roland Eichardt Uwe Schneider Ekkehard Schleussner PubMed Jens Haueisen Roland Eichardt Uwe Schneider Ekkehard Schleussner Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Construction of the Dirichlet to Neumann Boundary Operator for Triangles and Applications in the Analysis of Polygonal Conductors

This paper introduces a fast and accurate method to investigate the broadband inductive and resistive behavior of conductors with a nonrectangular cross section. The presented iterative combined waveguide mode (ICWM) algorithm leads to an expansion of the longitudinal electric field inside a triangle using a combination of parallel-plate waveguide modes in three directions, each perpendicular to one of the triangle sides. This expansion is used to calculate the triangle's Dirichlet to Neumann boundary operator. Subsequently, any polygonal conductor can be modeled as a combination of triangles. The method is especially useful to investigate current crowding effects near sharp conductor corners. In a number of numerical examples, the accuracy of the ICWM algorithm is investigated, and the method is applied to some polygonal conductor configurations.

New physics at a Super Flavor Factory

The potential of a Super Flavor Factory (SFF) for searches of New Physics is reviewed. While very high luminosity B physics is assumed to be at the core of the program, its scope for extensive charm and tau studies are also emphasized. The possibility to run at the Upsilon(5S) is also very briefly discussed; in principle, this could provide very clean measurements of B_s decays. The strength and reach of a SFF is most notably due to the possibility of examining an impressive array of very clean observables. The angles and the sides of the unitarity triangle can be determined with unprecedented accuracy. These serve as a reference for New Physics (NP) sensitive decays such as B^+ ->tau^+ nu and penguin dominated hadronic decay modes, providing tests of generic NP scenarios with an accuracy of a few percent. Besides, very precise studies of direct and time dependent CP asymmetries in radiative B decays and forward-backward asymmetry studies in B-> X_s l^+ l^- and numerous null tests using B, charm and tau decays are also likely to provide powerful insights into NP. The dramatic increase in luminosity at a SFF will also open up entirely new avenues for probing NP observables, e.g. by allowing sensitive studies using theoretically clean processes such as B -> X_s nu nubar. The SFF is envisioned to be a crucial tool for essential studies of flavor in the LHC era, and will extend the reach of the LHC in many important ways.

Powdery Mildew of Dogwoods: Current Status and Future Prospects.

Cornus is a large genus of trees and shrubs that are collectively referred to as dogwoods. Flowering dogwood (C. florida L.) and kousa dogwood (C. kousa (F. Buerger ex Miq.) Hance) and interspecific hybrids of these species are popular ornamental trees that are known for their showy bracts, red berries (drupes), and/or fall color. Other species that are commercially grown for specialty markets include the pagoda dogwood (C. alternifolia L.), giant dogwood (C. controversa Hemsl.), cornelian cherry (C. mas L.), Pacific dogwood (C. nuttallii Aud.), and redosier dogwood (C. sericea L.). The foliage of native species, such as flowering dogwood and pagoda dogwood, is high in calcium (12) in quantities above what is needed for skeletal growth of wildlife; it is the preferred browse material for lactating does in late spring while many other trees are still leafless (13,22). The berries of flowering dogwood have high oil content and provide mast for numerous species of migrant songbirds, wild turkeys, and large and small mammals (22). For many years, nurseries that produced flowering and kousa dogwoods had the luxury of working with relatively diseasefree crops. Disease management and control costs were minimal and estimated at approximately $120/ha/year. In the late 1970s, flowering and kousa dogwoods were threatened by a new disease, dogwood anthracnose, caused by Discula destructiva (39), which was reviewed by Daughtrey et al. (3). In 1994, another disease, powdery mildew, reached epiphytotic levels in flowering dogwoods. Tens of millions of dollar’s worth of dogwoods were destroyed and millions of cultivated seedlings lost their commercial value because formal management strategies were not formulated. In subsequent years, fungicide management costs were estimated to be $1,975/ha/year. Many small producers of dogwoods terminated production of the tree because they could not afford the additional overhead or were not inclined to continue routine fungicide sprays every 2 weeks from May to October. Powdery mildew on C. florida was first reported in 1887 by Burrill and Earle (1), but this disease was rarely reported on flowering dogwood in the United States before 1994. However, the disease appeared simultaneously in forest, landscape, and nursery plantings statewide in Alabama in 1994 (8). Similar outbreaks of powdery mildew were observed in Tennessee, where many nursery fields of flowering dogwood were abandoned (Fig. 1). Powdery mildew has emerged as a nationwide disease of flowering dogwood (2). Although the host side of the disease triangle remained constant, we do not know whether the change of frequency and severity of powdery mildew in flowering dogwood was due to a change in the pathogen or a change in the environment.

The evolution of transformation media in spherical trigonometry in 17th- and 18th-century China, and its relation to “Western learning”

Problems of spherical trigonometry in 17th- and 18th-century China were often reduced to problems in plane trigonometry and then solved by means of the proportionality of corresponding sides of similar right triangles. Nevertheless, in the literature on the history of Chinese mathematics, there is not much discussion on the transformation and reduction of spherical problems to the plane, and how the techniques utilized for such transformations evolved over time. In this article, I investigate the evolution of the transformation media involved. I will show that in the trigonometric treatises by Mei Wending (1633–1721) and Dai Zhen (1724–1777), the authors’ views on Western learning shaped their choices of transformation media, and conversely their choices of transformation media offered support to their views on trigonometry in the debate of Chinese versus Western methods. Based on my analysis, I also propose a reassessment of Dai’s treatise of trigonometry, which was controversial ever since its publication in the 18th century.

Update on angles and sides of the CKM unitarity triangle from BABAR

We report several recent updates from the BABAR Collaboration on the matrix elements | V c b | , | V u b | , and | V t d | of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix, and the angles β and α of the unitarity triangle. Most results presented here are using the full BABAR ϒ ( 4 S ) data set.

Curvature-Based Environment Description for Robot Navigation Using Laser Range Sensors

This work proposes a new feature detection and description approach for mobile robot navigation using 2D laser range sensors. The whole process consists of two main modules: a sensor data segmentation module and a feature detection and characterization module. The segmentation module is divided in two consecutive stages: First, the segmentation stage divides the laser scan into clusters of consecutive range readings using a distance-based criterion. Then, the second stage estimates the curvature function associated to each cluster and uses it to split it into a set of straight-line and curve segments. The curvature is calculated using a triangle-area representation where, contrary to previous approaches, the triangle side lengths at each range reading are adapted to the local variations of the laser scan, removing noise without missing relevant points. This representation remains unchanged in translation or rotation, and it is also robust against noise. Thus, it is able to provide the same segmentation results although the scene will be perceived from different viewpoints. Therefore, segmentation results are used to characterize the environment using line and curve segments, real and virtual corners and edges. Real scan data collected from different environments by using different platforms are used in the experiments in order to evaluate the proposed environment description algorithm.

“Empathic Attunement”: Cvetaeva's and Pasternak's Literary Tributes to Rilke

In the summer of 1926, three great poets of the twentieth century – Tsvetaeva, Pasternak, and Rilke – exchanged letters. This three-way epistolary exchange conducted by all three poets in German ended several months later, after Rilke's death from leukemia. The correspondence first saw the light in the German edition in the 1980's, then, gradually, it started appearing in other languages, including Russian. It has drawn comments from such a notable critic as Susan Sontag. Tsvetaeva's long poem, ‘Novogodnee’, written shortly after Rilke's death, was analyzed extensively by Joseph Brodsky. In my paper, I provide brief readings of three literary tributes to Rilke by Tsvetaeva and Pasternak. I use the psychological concept of “empathic attunement”, worked out by the prominent psychologist Heinz Kohut. I find that reading the literary tributes through the concept of empathy points to the human, as opposed to the mythical side of this fascinating literary triangle.

Flow with Slip Between Coaxial Cylinders and in an Equilateral Triangular Pipe

The Navier-Stokes equations are solved exactly, assuming the Navier slip boundary condition, for flow between coaxial circular cylinders (with possibly different slip lengths at the inner and outer walls), and flow in an equilateral triangular pipe. The velocity fields and total flow rates are found analytically. A relatively small slip length can lead to a large increase in the total rate of fluid flow: in the triangular pipe case the flow doubles when the slip length is only about 7.5% of the triangle side.

Affine-invariant contours recognition using an incremental hybrid learning approach

In this paper, a planar shape recognition system is proposed. This proposal is based on a global incremental scheme which combines two learning mechanisms: the Incremental Non-parametric Discriminant Analysis and the mode analysis method. At the feature selection stage, a novel adaptive curvature estimator for shape characterization is presented. This method describes the planar shape using an affine-invariant triangle-area representation obtained from its closed contour. Contrary to previous approaches, the triangle side lengths at each contour point are adapted to the local variations of the shape, removing noise from the contour without missing relevant points. In order to reduce the dimensionality of the shape descriptor, an Incremental Non-parametric Discriminant Analysis is conducted to seek directions for efficient discrimination (incremental eigenspace learning). At the classification stage, the incremental mode analysis is employed to classify feature vectors into a set of spherically-shaped groups (incremental prototype learning). The classification is conducted based on the k-nearest neighbor approach whose prototypes are updated by the mode analysis method. This scheme enables a classifier to learn incrementally, on-line, and in one-pass. Experimental results show that the proposed shape recognition system is well suited for shape indexing and retrieval.

On the greatest prime factor of sides of a Heron triangle

A Heron triangle is a triangle whose sides a, b, c and area A = s(s − a)(s − b)(s − c) are integers. Here, s = (a + b + c)/2 is the semiperimeter of . The triangle is called reduced if gcd(a, b, c) = 1. For a positive integer n let P(n) be the largest prime factor of n with the convention that P(1) = 1. In [5], it was shown that P(A) → ∞ as max{a, b, c} → ∞ through triples which are sides of reduced Heron triangles. In [4], it was shown that also P(abc) → ∞ again as max{a, b, c} → ∞ through triples which are sides of reduced Heron triangles. Here, we improve this to: Theorem 1. P(bc) goes to infinity as max{a, b, c} goes to infinity through triples which are sides of reduced Heron triangles .

Permutation asymmetry of the relativistic velocity addition lawand non-Euclidean geometry

The asymmetry of the relativistic addition law for noncollinear velocities under the velocity permutation leads to two modified triangles on a Euclidean plane depicting the addition of unpermuted and permuted velocities and the appearance of a nonzero angle ω between two resulting velocities. A particle spin rotates through the same angle ω under a Lorentz boost with a velocity noncollinear to the particle velocity. Three mutually connected three-parameter representations of the angle ω, obtained by the author earlier, express the three-parameter symmetry of the sides and angles of two Euclidean triangles identical to the sine and cosine theorems for the sides and angles of a single geodesic triangle on the surface of a pseudosphere. Namely, all three representations of the angle ω, after a transformation of one of them, coincide with the representations of the area of a pseudospherical triangle expressed in terms of any two of its sides and the angle between them. The angle ω is also symmetrically expressed in terms of three angles or three sides of a geodesic triangle, and therefore it is an invariant of the group of triangle motions over the pseudo-sphere surface, the group that includes the Lorentz group. Although the pseudospheres in Euclidean and pseudo-Euclidean spaces are locally isometric, only the latter is isometric to the entire Lobachevsky plane and forms a homogeneous isotropic curved 4-velocity space in the flat Minkowski space. In this connection, relativistic physical processes that may be related to the pseudosphere in Euclidean space are especially interesting.