Ellipsoidal Type Research Articles

A comparative ultrastructural study on the nanoscale extrusomes of tintinnids (Alveolata, Ciliophora, Spirotricha) and their phylogenetic significance

The capsules, putative extrusomes in tintinnid ciliates, are known since 1971. Based on their ultrastructure, shape, and size, five capsule types were distinguished and suggested to be of phylogenetic significance. However, detailed morphometric data and transmission electron micrographs are lacking to verify former conclusions. In the current study, comprehensive analyses of transmission electron microscopic data were performed, investigating 14 species from 13 genera and more than seven families collected in European coastal waters and in the Northeast Pacific. Our data suggest two main capsule types (large and ampulliform vs small and ellipsoidal/ovoidal) each including two subtypes characterised by their internal structures. Species groupings inferred from the capsule (sub-)types emerge also as closely related in gene trees. Additionally, the ampulliform type unites the Undellidae, Xystonellidae, and Tintinnid clade 2, while the shared possession of the small ellipsoidal type proposes a close relationship of Tintinnid clade 11 with the Rhabdonellidae and Cyttarocylididae. Thus, the capsules provide promising features to shed light on several unresolved evolutionary relationships among tintinnid genera and families; yet, information on capsules is still missing for many monophyletic groupings. Finally, we provide the first ultrastructural clues for the extrusive character of these organelles.

Robust Control of a Bimorph Piezoelectric Robotic Manipulator Considering Ellipsoidal-Type State Restrictions

The current study presents an adaptive control approach to solve the tracking trajectory problem for a robotic manipulator that uses a gripper based on bimorph piezoelectric actuators. The development of an adaptive gain state feedback form that considers the state restrictions is proposed using a novel class of barrier Lyapunov function that drives the effective control of joints and piezoelectric actuators. The proposed method allows for the inclusion of complex combinations of state restrictions in the Lyapunov function, yielding the construction of differential forms for the gains in the controller that can handle the evolution of trajectories of the robotic arm inside the restricted region. The proposed control design successfully tracks reference trajectories for both joints of the robotic arm as well as the motion of the piezoelectric device during several operative scenarios. A comprehensive experimental study evaluates the effect of introducing state-dependent gain considering state restrictions of the ellipsoidal type. The comparison of the mean square error confirms the contributions of the developed control action, showing better tracking quality for less control power with the same evaluation, which is a desirable characteristic in the controlled motion of micromanipulators. The proposed controller solves the tracking trajectory problem for the micromanipulation system, satisfies the motion restrictions, and allows better tracking performance to be enforced. Furthermore, comparison of the obtained trajectories seems to validate the proposed controller’s contribution concerning a feedback form with fixed gains.

Pressure fluctuation measurement in pressure vessels

Pressure vessels are mechanical devices that act as a reservoir of fluids at pressure more or less than atmospheric pressure. This research focuses on the application of the pressure vessel for hydraulic testing of hydro turbines to maintain uniform velocity profile and to suppress the pressure surge in the pipeline. An initial assumption for the design of a thin-walled horizontal type pressure vessel with the ellipsoidal type of head is based on the mathematical relations as per ASME code, Section VIII, Division I, for an operating pressure of 0.3 MPa and design pressure of 0.6 MPa. The pressure vessel has been placed, close to outlet of the main pump to prevent the water hammering in the pipeline. The measurement of the pressure fluctuations at the inlet, outlet, and inside of the vessel, due to the dynamic action of fluid forced by the pump are recorded. The study attempts to relate the use of pressure vessels to generate stable flow and pressure at the outlet for hydraulic testing of turbines.

Effects of Laptop use on Wrist in Students and Teachers of Different Universities during Covid-19

The wrist is an ellipsoidal type (condyloid) of articulation synovial is permitting movements at two axes. The anatomical name of the joint is the radio-carpal joint [1-5].It presents a sinuous opposing. The concave proximal articular surface is formed by the lower end of the radius and the articular disc of the inferior radio-ulnar joint. The reciprocally convex distal articular surface is formed by the scaphoid, lunate and triquetral bones from lateral to the medial side. The joint capsule surrounds the wrist and is attached to the distal ends of the radius and ulna and proximal rows of carpals excluding the pisiform. Strong ligaments strengthen and stabilize the joint from the sides, and on the ventral and dorsal surfaces. Repeated episodes of mechanical stress can cause the event of repetitive motion injuries or overuse injuries, which when including poor posture and biomechanics put much strain on the joints. They usually develop slowly over an extended period of your time. Wrists are one of the foremost common sites of repetitive motion injury. Therefore this research was designed to study the effect of laptop usage among physiotherapists(students and teachers). This study may give awareness to the individual to avoid or minimize the overuse of laptops and therefore the complications by breaking bad habits, practicing recommended/approved posture while using the laptop, and modulating the planning of the keyboards. Due to covid 19 era, the use of laptops and computer has significantly increased among students and teachers of different universities for teaching purposes. Therefore the study was designed to study the impact of laptop use on the wrist in students and Teachers duringcovid 19.Objective: To find the impact of laptop use on the wrist in Physiotherapist during covid 19

Application of a triangular finite element with Lagrange correction factors in calculations of thin shells of ellipsoidal type

The study of the stress-strain state of a thin shell of an ellipsoidal type was carried out. The finite element method was used as a research tool using the triangular fragment of the middle surface as the discretization element. The nodal variable parameters of the triangular element of discretization selected the components of the displacement vector, their first and second derivatives with respect to global curvilinear coordinates. Fifth-degree polynomials were used as polynomial functions. To improve the consistency of the triangular element of discretization on the boundaries of adjacent elements, the Lagrange correction factors in the nodes entered in the midpoints of the sides of the triangular element were additionally used as unknowns. The analysis of the results of the calculation of the thin shell of the ellipsoidal type showed high efficiency of using the modified triangular finite element.

A Full Electromagnetic Particle-in-Cell Code To Model Collision-less Plasmas in Magnetic Traps

A lot of plasma physics problems are not amenable to exact solutions due to many reasons. It is worth mentioning among them, for example, nonlinearity of the motion equations, variable coefficients or non lineal conditions on known or unknown borders. To solve these problems, different types of approximations which are combinations of analytical and numerical simulation methods are put into practice. The problem of plasma behavior in numerous varieties of a minimum-B magnetic trap where the plasma is heated under electron cyclotron resonance (ECR) conditions is the subject of numerical simulation studies. At present, the ECR minimum-B trap forms the principal part of the multi-charge ion sources. There are different numerical methods to model plasmas. Depending of both temperature and concentration, these can be classified in three main groups: fluid models, kinetic models and hybrid models. The fluid models are the most simple way to describe the plasma from macroscopic quantities, which are used for the study of highly collisional plasmas where the mean free path is much smaller than size of plasma (l_mfp > L) from the solution of the Boltzmann or Vlasov equation, respectively [2]. For kinetic simulations there are different method to solve the Boltzmann or Vlasov equation, being the Particle-In-Cell (PIC) codes one the most popular. The hybrid model combine both the fluid and kinetic models, treating some components of the system as a fluid, and others kinetically; which are used for the study of plasmas, may use the PIC method for the kinetic treatment of some species, while other species (that are Maxwellian) are simulated with a fluid model. In this work, a scheme of the relativistic Particle-in-Cell (PIC) code elaborated for an ECR plasma heating study in minimum-B traps is presented. For a PIC numerical simulation, the code is applied to an ECR plasma confined in a minimum-B trap formed by two current coils generating a mirror magnetic configuration and a hexapole permanent magnetic bars to suppress the MHD instabilities. The plasma is maintained in a cylindrical chamber excited at TE_111 mode by 2.45 GHz microwave power. In the obtained magnetostatic field, the ECR conditions are fulfilled on a closed surface of ellipsoidal type. Initially, a Maxwellian homogeneous plasma from ionic temperature of 2 eV being during 81.62 ns, that correspond to 200 cycles of microwaves with an amplitude in the electric field of 1 kV/cm is heated. The electron population can be divided conditionally into a cold group of energies smaller than 0.2 keV, a warm group whose energies are in a range of 3 − 10 keV and hot electrons whose energies are found higher than 10 keV.

Estimation problems for uncertain nonlinear dynamical systems with ellipsoidal state constraints

The paper deals with the estimation problems for uncertain nonlinear dynamical systems in the case when a probabilistic description of noise and errors is not available, but only bounds on them known. Such models are found in many applied areas ranged from engineering problems from physics to economics as well as to biological and ecological modeling when it occurs that a stochastic nature of the errors is questionable because of limited data or because of complexity and nonlinearity of the model. As alternative to a stochastic characterization, a so-called set-membership approach has been proposed and intensively developed in the last decades. The solution of many control and estimation problems under uncertainty involves constructing reachable sets and their analogs. For models with linear dynamics under such set-membership uncertainty, there are several constructive approaches, which allow finding effective estimates of reachable sets. Certainly, concrete problems are mostly nonlinear in their parameters and the set of feasible system states is usually non-convex or even non-connected. The key issue in nonlinear set-membership estimation is to find suitable techniques, which produce related bounds for the set of unknown system states without being too computationally demanding. Here the problem of estimating reachable sets of nonlinear dynamical control systems with combined bilinear and quadratic nonlinearity and with uncertainty in initial states is studied. Applying results of the theory of trajectory tubes of control systems and related techniques of differential inclusions theory we present approaches that allow finding the upper ellipsoidal estimates of reachable sets. The main new result consists in obtaining ellipsoidal estimates for reachable sets of nonlinear dynamical system with additional state constraint of ellipsoidal type. Related numerical algorithms, examples and results of computer simulations are included.

Ellipsoidal Neumann geodetic boundary-value problem based on surface gravity disturbances: case study of Iran

An ellipsoidal Neumann type geodetic boundary-value problem (GBVP) for the computation of disturbing potential on the surface of the Earth based on the surface gravity disturbance as the boundary data is formulated. The solution methodology of the GBVP can be algorithmically summarized as follows: (i) using global navigation satellite systems (GNSS) coordinates of the gravity stations, the surface gravity disturbances are generated as the boundary data. (ii) Applying the deflection correction to the gravity disturbances to arrive at the derivative of the surface disturbing potential along the ellipsoidal normal. (iii) Removing the low frequencies part of the gravity field using harmonic expansion to degree and order 110. (iv) Using the short wavelength part of the corrected gravity disturbances derived in the previous section as the boundary data within the constructed GBVP to derive the short wavelength disturbing potential over the Earth surface. (v) The computed shortwave length signals of disturbing potentials are converted to disturbing potential values by restoring the removed effects.

Spatial distribution of dinoflagellate resting cysts in Yellow Sea surface sediments

Yellow Sea surface sediment samples collected on October 15-31, 2003 were analyzed using the palynological process to investigate the spatial distribution of dinoflagellate resting cysts. The sampling areas comprised four latitudinal transects, the northernmost of which was located off the Shandong Peninsula, China and the southernmost off Jeju Island, Korea. Each transect line was composed of six to nine stations, spanning the distance between the Chinese and Korean coasts. Twenty-five different types of dinoflagellate cysts were identified. Gonyaulax scrippsae, Alexandrium spp. (ellipsoidal type), and G. spinifera were the most dominant at all stations surveyed. Dinoflagellate cysts belonging to the Gonyaulacales comprised over 50% of all cysts collected. The latitudinal distribution trend showed that cyst concentrations along the two middle transects were much higher than those along the two northern and southern transects. Cyst concentrations in the offshore central areas reached their highest values within each transect and gradually decreased toward the Chinese and Korean coasts. Overall, cyst concentrations were markedly elevated in the offshore central Yellow Sea areas and gradually decreased outward in all four directions. This concentric cyst distribution pattern was consistent with the hydrographic features of the Yellow Sea, such as circular current systems, sedimentary properties, and water depth.

Assessment of the Validity of the Double Superhelix Model for Reconstituted High Density Lipoproteins: A COMBINED COMPUTATIONAL-EXPERIMENTAL APPROACH

For several decades, the standard model for high density lipoprotein (HDL) particles reconstituted from apolipoprotein A-I (apoA-I) and phospholipid (apoA-I/HDL) has been a discoidal particle ∼100 Å in diameter and the thickness of a phospholipid bilayer. Recently, Wu et al. (Wu, Z., Gogonea, V., Lee, X., Wagner, M. A., Li, X. M., Huang, Y., Undurti, A., May, R. P., Haertlein, M., Moulin, M., Gutsche, I., Zaccai, G., Didonato, J. A., and Hazen, S. L. (2009) J. Biol. Chem. 284, 36605-36619) used small angle neutron scattering to develop a new model they termed double superhelix (DSH) apoA-I that is dramatically different from the standard model. Their model possesses an open helical shape that wraps around a prolate ellipsoidal type I hexagonal lyotropic liquid crystalline phase. Here, we used three independent approaches, molecular dynamics, EM tomography, and fluorescence resonance energy transfer spectroscopy (FRET) to assess the validity of the DSH model. (i) By using molecular dynamics, two different approaches, all-atom simulated annealing and coarse-grained simulation, show that initial ellipsoidal DSH particles rapidly collapse to discoidal bilayer structures. These results suggest that, compatible with current knowledge of lipid phase diagrams, apoA-I cannot stabilize hexagonal I phase particles of phospholipid. (ii) By using EM, two different approaches, negative stain and cryo-EM tomography, show that reconstituted apoA-I/HDL particles are discoidal in shape. (iii) By using FRET, reconstituted apoA-I/HDL particles show a 28-34-Å intermolecular separation between terminal domain residues 40 and 240, a distance that is incompatible with the dimensions of the DSH model. Therefore, we suggest that, although novel, the DSH model is energetically unfavorable and not likely to be correct. Rather, we conclude that all evidence supports the likelihood that reconstituted apoA-I/HDL particles, in general, are discoidal in shape.

황해 남동부 해역 저질 내 와편모조류 휴면포자의 분포

To gain a greater understanding of the potential for future harmful algal bloom (HAB) outbreaks and to trace the dispersal paths of dinoflagellates, sediment samples were collected from 13 stations in the southeastern Yellow Sea. 23 different types of dinoflagellate resting cysts were identified from the samples. Protoceratium reticulatum (1-391 cells/g dry weight), Gonyaulax scrippsae (0-254 cells/g dry weight), G. spinifera (0-301 cells/g dry weight) and Alexandrium spp. (ellipsoidal type) (0-76 cells/g dry weight) were the dominant species at all surveyed stations. The overall distribution pattern demonstrated that the resting cyst densities were highest in the offshore area and decreased gradually toward the Korean coast. On the other hand, the composition rate of resting cysts of the heterotrophic dinoflagellate species to the total dinoflagellates was higher in the Korean coast region than in the offshore area. We supposed that this distribution pattern of dinoflagellate resting cysts appeared to be influenced by the hydrographic features and environmental conditions of the Yellow Sea.

Pulse control problems under ellipsoidal constraints: Constraint parameters sensitivity

Consideration is given to pulse control problems for the tube of trajectories of the linear differential system under incomplete information on the initial data. Apart from the ordinary requirement for boundedness of variation, a special constraint of the ellipsoidal type is imposed on control actions; at this constraint, vectors of jumps of generalized controls belong to the specified ellipsoid of the corresponding finite-dimensional space. The dependence of the variation of optimal pulse control that solves the control problem for the tube of trajectories on parameters of the ellipsoidal constraint on admissible controls is studied.

Comparison principle for equations of the Hamilton-Jacobi type in control theory

This paper deals with the comparison principle for the first-order ODEs of the Hamilton-Jacobi-Bellman and Hamilton-Jacobi-Bellman-Isaacs type which describe solutions to the problems of reachability and control synthesis under complete as well as under limited information on the system disturbances. Since the exact solutions require fairly complicated calculation, this paper presents the upper and lower bounds to these solutions, which in some cases may suffice for solving such problems as the investigation of safety zones in motion planning, verification of control strategies or of conditions for the nonintersection of reachability tubes, etc. For systems with original linear structure it is indicated that present among the suggested estimates are those of ellipsoidal type, which ensure tight approximations of the convex reachability sets as well as of the solvability sets for the problem of control synthesis.

External ellipsoidal estimates of the attainability sets of differential impulse systems

The problems of estimating a tube of solutions of dynamic systems described by differential equations containing generalized (impulse) control functions are considered. It is supposed that a special constraint of an ellipsoidal type is imposed on the control, and, in particular, that the vectors of jumps of generalized equations are to belong to a specified ellipsoid of the appropriate finite-dimensional space. To obtain external estimates of the attainability sets of the system, the results of ellipsoidal calculus, which is well developed nowadays, are applied. A new method for constructing estimates based on the external ellipsoidal approximation of the convex set of a union of ellipsoids is also proposed. Particular examples of constructing estimates of the attainability set are considered based on the proposed methods.

Ellipsoidal geoidal undulations (ellipsoidal Bruns formula): case studies

The Bruns formula is presented in its nonlinear form for any type of reference fields and reference equipotential surfaces. The classical Bruns formula is derived from the reference field of the first term of spherical harmonic expansion (w=gm/r) based on the reference equipotential sphere Sr02 of radius r0=gm/W0. W0 is the potential value of the Gauss–Listing geoid. Four reference fields of ellipsoidal type, namely (1) the first term of ellipsoidal (spheroidal) harmonic expansion of the external gravitational field of the Earth, (2) the first term of ellipsoidal harmonic expansion of the external gravitational potential field of the Earth plus the centrifugal field, (3) the Somigliana–Pizzetti gravity potential field, and (4) the ellipsoidal harmonic expansion of the external gravitational field of the Earth to degree/order 50/50 plus the centrifugal field are considered. Based on each of the aforementioned ellipsoidal fields, the corresponding Bruns formula up to second-order nonlinear terms is computed. The ellipsoidal Bruns formula has been applied for a geoid computation in the state of Baden–Wurttemberg (Germany). More specifically, the geoidal undulations computed based on the first three reference ellipsoidal fields of choice are compared with the geoidal undulation computed based on the fourth reference field of ellipsoidal harmonic expansion up to degree/order 50/50 plus the centrifugal field. The results indicate that the Bruns formula computed based on the first two reference ellipsoidal fields does not provide centimetre accuracy unless the nonlinear terms of the Bruns formula up to degree 3 in terms of disturbing potential values are incorporated. However, the Bruns formula computed based on the Somigliana–Pizzetti reference field offers millimetre accuracy even for the linear part of the ellipsoidal Bruns formula. Owing to the fact that the ellipsoidal Bruns formula based on the Somigliana–Pizzetti field has the advantage of fulfilling the Gauss criterion of zero value for the global mean of geoidal undulations over the reference equipotential surface, the ellipsoidal Bruns formula based on the Somigliana–Pizzetti reference field is recommended for up-to-date geoid computations with sub-millimetre accuracies.

Mixed cylindric map projections of the ellipsoid of revolution

The mixed spherical map projections of equiareal, cylindric type are based upon the Lambert projection and the sinusoidal Sanson–Flamsteed projection. These cylindric and pseudo-cylindric map projections of the sphere are generalized to the ellipsoid of revolution (biaxial ellipsoid). They are used in consequence by two lemmas to generate a horizontal and a vertical weighted mean of equiareal cylindric map projections of the ellipsoid of revolution. Its left–right deformation analysis via further results leads to the left–right principal stretches/eigenvalues and left–right eigenvectors/eigenspace, as well as the maximal left–right angular distortion for these new mixed cylindric map projections of ellipsoidal type. Detailed illustrations document the cartographic synergy of mixed cylindric map projections.

Design for nonsymmetrical statistical distributions

This paper presents a method for approximation of the constraint region and design centering for statistically distributed design parameters. Arbitrary uncorrelated probability density functions (p.d.f.'s) are considered, including truncated ones. The approximation problem is formulated deterministically and solved by optimization. The constraint region is approximated by a family of second-order ellipsoidal type functions. Formulation of the approximation problem takes into account statistical distributions of parameters, to be used in subsequent design centering. A special metric replaces evaluation of a multidimensional (yield) integral over the constraint region by simple integrals over fixed intervals. An additional outcome of the approximation process is location of a nominal design that increases yield.

Helical tubulate inclusion compounds

Abstract The inclusion properties of the first helical tubuland diol hosts 1–5 have been surveyed and are reported. Bicyclic diol 1 forms helical tubulate inclusion compounds with most small solvent molecules, but with certain phenols hydrogen bonded co-crystalline materials are produced instead. Diol 2 yields helical tubulates with larger guest molecules, but if smaller solvents are used then an alternative host system is obtained. This has the guests trapped in ellipsoidal cavities located along constricted canals and is termed the ellipsoidal clathrate type. In some cases both inclusion types can be produced from 2 by varying the experimental conditions. The free volume present in the helical tubuland lattices of 3 and 5 is insufficient for guest inclusion. Diol 4 has the largest void space and can form inclusion compounds with large molecules such as ferrocene and squalene. X-ray crystal structures of representative examples of these compounds are discussed.

Guest control of diol inclusion host lattices

A survey of the multimolecular inclusion compounds formed bysyn-2,syn-7-dihydroxy-2,7-dimethyltricyclo[4.3.1.13,8]undecane1 and 34 guest molecules shows that two inclusion crystal structures are commonly obtained, namely the helical tubulate inclusion lattice and the ellipsoidal clathrate structure type. Interactions between host and guest are necessarily weak since the host surface is hydrocarbon. Small differences in the guest molecules can tip the balance between alternative inclusion lattices, one of which is chiral. For the first time precise guest locations in the helical tubulate structure have been obtained by X-ray diffraction analysis. Crystal data:1·CCl4: space groupP3121,a=13.2812(2),c=6.904(1) A, unit cell contents 3(C13H22O2) + 1.2CCl4,R=0.044;1·BrCH2CH2CH2Br: space groupP3121,a=13.206(2),c=6.915(2) A, unit cell contents 3(C13H22O2)+ BrCH2CH2CH2Br,R=0.042;1.0- xylene: space groupP3121,a=13.380(2),c=6.905(1) A, unit cell contents 3(C13H22O2) + 1.2 C8H10,R=0.042.

Algorithmic insights and a convergence analysis for a Karmarkar-type of algorithm for linear programming problems

This paper is concerned with a modification of a recently proposed variant of Karmarkar's algorithm for solving linear programming problems. In analyzing this variant, we exhibit interesting and useful relationships of these types of algorithms with barrier function methods, and subgradient optimization procedures involving space dilation techniques, which subsume the well-known ellipsoidal type of algorithms. Convergence of this variant is established under certain regularity conditions. We also provide remarks on how to obtain dual variables or Lagrange multipliers at optimality.