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1
Biswas, Ranita, Sebastiano Cultrera di Montesano, Herbert Edelsbrunner, and Morteza Saghafian. "Continuous and Discrete Radius Functions on Voronoi Tessellations and Delaunay Mosaics." Discrete & Computational Geometry 67, no. 3 (February 7, 2022): 811–42. http://dx.doi.org/10.1007/s00454-022-00371-2.
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AbstractThe Voronoi tessellation in $${{{\mathbb {R}}}}^d$$ R d is defined by locally minimizing the power distance to given weighted points. Symmetrically, the Delaunay mosaic can be defined by locally maximizing the negative power distance to other such points. We prove that the average of the two piecewise quadratic functions is piecewise linear, and that all three functions have the same critical points and values. Discretizing the two piecewise quadratic functions, we get the alpha shapes as sublevel sets of the discrete function on the Delaunay mosaic, and analogous shapes as superlevel sets of the discrete function on the Voronoi tessellation. For the same non-critical value, the corresponding shapes are disjoint, separated by a narrow channel that contains no critical points but the entire level set of the piecewise linear function.
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Abo-elenein, Mohamed Hemdan, Salah Eldeen Ibrahim Hassab Elnaby, Amin Fahim Hassan, and Afaf Mahmoud Abd-Rabou. "Modeling for Generating Femtosecond Pulses in an Er-Doped Fiber Using Externally Controlled Spectral Broadening and Compression Mechanisms." Photonics 9, no. 4 (March 22, 2022): 205. http://dx.doi.org/10.3390/photonics9040205.
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A model for generating femtosecond laser pulses from a low-power mode-locked laser of moderate temporal half-width was proposed. This was achieved by injecting the pulse into a single-mode inverted-populated Er-doped fiber where self-focusing and absorption were avoided. To initiate spectral broadening, the pulse was phase-modulated by subjecting a part of the fiber to an electric field of suitable intensity and frequency generated into a circular capacitor. To stimulate temporal compression, the phase-modulated pulse was introduced into a combination of two prism sets located symmetrically with respect to the x-axis. After passing the pulse through the first prism set, its spectral components were spatially separated in the y-axis. The spectral phases were manipulated by redirecting the spectral components through a slab cross-section that was subjected to a spatially modulated DC electric field. After passing the slab, the pulse is directed into the second prism set, where the spectral components were spatially overlapped and propagated outside the compressor with the same slope and dimension as before entering the compressor. Constructive super positioning of the phase-manipulated spectral components gave maximum intensity only at a specified location.
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Becker, J., K. Rademann, and F. Hensel. "Electronic and Geometrical Structure of Se5, Se6, Se7, and Se8." Zeitschrift für Naturforschung A 46, no. 5 (May 1, 1991): 453–61. http://dx.doi.org/10.1515/zna-1991-0513.
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AbstractThe vacuum-UV-photoelectron spectra of Se2, Se5, Se6, Se7, and Se8 have been recorded at a photon energy of h ν= 10.0 eV. The isolated molecules are examined in a supersonic molecular beam employing a new photoelectron-photoion coincidence technique. The structure of the photoelectron spectra of selenium molecules with even and odd numbers of atoms differs in a characteristic manner. While the spectra of Se6 and Se8 show one single broad band, three separated bands with different intensities are observed for Se5 and two for Se7. The spectra are compared to molecular orbital energy calculations based on theoretically supposed geometries. The comparison indicates that Se6 and Se8 have Dnd-symmetrical ring structures, whereas Se5 and Se7 are C1h-symmetrical rings
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Kock, Guillaume, Philippe Combette, Marwan Tedjini, Markus Schneider, Caroline Gauthier-Blum, and Alain Giani. "Experimental and Numerical Study of a Thermal Expansion Gyroscope for Different Gases." Sensors 19, no. 2 (January 17, 2019): 360. http://dx.doi.org/10.3390/s19020360.
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A new single-axis gas thermal gyroscope without proof mass is presented in this paper. The device was designed, manufactured and experimentally characterized. The obtained results were compared to numerical simulation. The working principle of the gyroscope is based on the deflection of a laminar gas flow caused by the Coriolis effect. A bidirectional hot air flow is generated by alternating activation of two suspended resistive micro-heaters. The heated gas is encapsulated in a semi-open cavity and the gas expands primarily inside the cavity. The thermal expansion gyroscope has a simple structure. Indeed, the device is composed of a micromachined cavity on which three bridges are suspended. The central bridge is electrically separated into two segments enabling to set up two heaters which may be supplied independently from each other. The two other bridges, placed symmetrically on each side of the central bridge, are equipped with temperature detectors which measure variations in gas temperature. The differential temperature depends on the rotational velocity applied to the system. Various parameters such as the heating duty cycle, the type of the gas and the power injected into the heaters have been studied to define the optimal working conditions required to obtain the highest level of sensitivity over a measurement range of around 1000°/s. The robustness of the device has also been tested and validated for a shock resistance of 10,000 g for a duration of 400 µs.
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Moore, D. W., and D. I. Pullin. "Inviscid separated flow over a non-slender delta wing." Journal of Fluid Mechanics 305 (December 25, 1995): 307–45. http://dx.doi.org/10.1017/s0022112095004642.
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We consider inviscid incompressible flow about an infinite non-slender flat delta wing with leading-edge separation modeled by symmetrical conical vortex sheets. A similarity solution for the three dimensional steady velocity potential Φ is sought with boundary conditions to be satisfied on the line which is the intersection of the wing sheet surface with the surface of the unit sphere. A numerical approach is developed based on the construction of a special boundary element or ‘winglet’ which is effectively a Green function for the projection of ∇2Φ = 0 onto the spherical surface under the similarity ansatz. When the wing semi-apex angle γo is fixed satisfaction of the boundary conditions of zero normal velocity on the wing and zero normal velocity and pressure continuity across the vortex sheet then leads to a nonlinear eigenvalue problem. A method of ensuring a condition of zero lateral force on a lumped model of the inner part of the rolled-up vortex sheet gives a closed set of a equations which is solved numerically by Newton's method. We present and discuss the properties of solutions for γ0 in the range 1.30 < γ <89.50. The dependencies of these solutions on γ0 differs qualitatively from predictions of slender-body theory. In particular the velocity field is in general not conical and the similarity exponent must be calculated as part of the global eigenvalue problem. This exponent, together with the detailed flow field including the position and structure of the separated vortx sheet, depend only on γ0. In the limit of small γ0, a comparison with slender-body theory is made on the basis of an effective angle of incidence.
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HARDMAN, J. R., and P. E. HANCOCK. "Moderately three-dimensional separated and reattaching turbulent flow." Journal of Fluid Mechanics 649 (April 13, 2010): 341–70. http://dx.doi.org/10.1017/s0022112009993478.
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A fully three-dimensional turbulent separated flow was set up such that it had a systematic link to two-dimensional flow, as a way of investigating the more complicated nature of this flow type. The central region of the flow was fully three-dimensional, but was bounded on its sides by regions of ‘spanwise invariance’ in which the flow was invariant in the lateral direction, or very nearly so. A special case of spanwise invariance, which is statistically two-dimensional, is one in which the streamlines are also coplanar, or at least nominally so in numerous experimental studies. Another aspect of the present arrangement is that the side regions should ideally provide well-defined boundary conditions. The separation was formed downstream of a doubly swept normal flat plate, forming a ‘v’-shaped separation line, mounted on the front of a splitter plate, mounted in the centre of the wind tunnel working section. The predominantly inward flow to the central region implies a negative lateral strain rate (∂W/∂z), but all nine strain rates are non-zero. Measurements were made using pulsed-wire anemometry techniques for mean velocities, Reynolds stresses and wall shear stress. Even though the sweep angle is mild at ±10°, the effect is to increase the bubble height by over 50% in its centre to create a ‘bulge’, symmetrical about the centreline. The degree of three-dimensionality is described as moderate in that the peak inflow velocity from the side regions is less than 0.2 of the free-stream velocity, but comparable with the peak in the reverse-flow velocity. A larger sweep angle would give a larger inflow velocity. A separate study (Cao & Hancock, Eur. J. Mech. B/Fluids, vol. 23, 2004, p. 519) has shown that the bulge persists very far downstream, so that accurate physical modelling of the separated region is likely to be important in modelling the flow well downstream. An intermediate region exists between the invariant side region and the bulge, where all the stress levels are reduced, as would be expected from the effects of streamline convergence. Although overall there is a flow inward to the centre (streamline convergence), part of the overlying shear layer is subjected to diverging flow and an intensification of Reynolds stresses near the centre of the bulge.
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Savina, Lyudmila, Valeriy Savin, and Valentin Osadchy. "The rolls calibration development and caliber drawings preparation with the computer software for the bent profiles production and straight-through pipes formation for laser welding." MATEC Web of Conferences 224 (2018): 04029. http://dx.doi.org/10.1051/matecconf/201822404029.
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A computer program has been created for selecting the profiling route, calculating the rolls for the manufacture of bent symmetrical and asymmetric profiles of virtually any real configurations with the issuance of a complete set of drawings. The algorithm of the program is based on the mathematical model of the strip profiling process, which allows geometric and energy-strength parameters calculation. To create an algorithm for designing roll calibrations to produce curved profiles, a unified description of the shape of the profile was proposed. The left and right halves of the cross section of the profile are treated as separate sets of alternating straight sections and rounds. The configuration of each of them for one and the other profile half is entered separately, starting from the middle. For each point of conjugation (the beginning and end of the section), the coordinates, the rounding radius and the rotation angle are specified (or calculated in the future). The accepted profile shape description makes it possible to compile a general algorithm for calculating the roll calibrations of virtually any profiles, and not to develop an algorithm for each profile or group of profiles.
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Islam, Shahnoor, Sadruddin Al Masud, Nazmul Haider Chawdhary, M. Mozaffar Hossain, SM Shafiqul Alam, M. Abul Kalam, Asit Chandra Sarkar, et al. "Successful Separation of Conjoined Twins: Experience of a Tertiary Care Hospital." Bangladesh Journal of Child Health 42, no. 2 (July 31, 2018): 73–78. http://dx.doi.org/10.3329/bjch.v42i2.37762.
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Background: The separation of conjoined twins presents a unique challenge to many pediatric surgical specialties. Meticulous preoperative investigations, planning and multidisciplinary team approach led by pediatric surgeon contribute to the success of surgical separation. The aim of this study is to share our experiences of one hospital to enhance skill for treating conjoined twins regarding anatomic variations, investigations, surgical aspects, outcomes and rehabilitation.Methodology: All cases of symmetrical conjoined twins who were treated from July 2009 to February 2018 at the Pediatric Surgery Department of Dhaka Medical College Hospital, Dhaka, Bangladesh were included in this prospective type of study. All types of parasitic twins were excluded. Prenatal ultrasound diagnosis, gender, birth weight, anatomy of the twins, the age and weight at the time of the separation surgery, the length of surgery, the duration of anesthesia during the separation surgery, a detailed description of the separation surgery, the type of skin closure, postoperative complications and death were studied.Results: There were three sets of thoraco-omphalo-ischiopagus twins, one set of thoraco-omphalopagus twins, one set of pygopagus twins. Three sets had no prenatal visit or ultrasound evaluation. Two sets of conjoined twins were failed to separate due to the complexity of the organs that were shared by both twins and instability leading to death. Only one set of pygopagus twins was successfully separated. Emergency colostomies were done on pygopagus twins due to the presence of anorectal anomalies. The surgical survival rate was 100%. One set of twins who did not undergo separation due to refusal of treatment was currently alive. One set of twins was under evaluation and currently alive.Conclusion: The overall success of conjoined twin separation depends on the experience and preparedness of treating team led by pediatric surgeon and resources available at the hospital. No single discipline can expect to have all the necessary talents.Bangladesh J Child Health 2018; VOL 42 (2) :73-78
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Goja, Bojan. "Giovanni Vendramin i iluminacije u inkunabulama samostana Sv. Frane u Šibeniku." Ars Adriatica, no. 5 (January 1, 2015): 115. http://dx.doi.org/10.15291/ars.521.
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The article analyses the illuminations of two incunables which are housed in the monastery of St Francis at Šibenik. The front page of the incunable of John Duns Scotus’ Scriptum in quattuor libros Sententiarum Petri Lombardi (Johannes de Colonia et Johannes Manthen, Venice, 1477) is decorated with high-quality figural and phytomorphic illuminations. In the corners of the decorative frame in the upper margin are the figures of a heronand a monkey. Vertical sections of the frame are filled with flowers, leaves and berries in the colour blue, green and cyclamen pink and with numerous stylized golden burdock flowers (Arctium). The central part of the frame in the upper and lower margin is filled with dense, symmetrically placed thick leaves in the colour blue, green, purple and cyclamen pink with a stylized golden burdockflower (Arctium) appearing here and there. In the centre of the page is a crest composed of two fields separated by a horizontal line; the upper on is red and the lower one white. Two winged putti are set in the corners andthey hold red ribbons. Each wears a necklace made of red corals and classical sandals on their feet. They landscape around them is arid and there is only one tree, its bark dry, standing in it. The rocky ground with jagged edges is covered in small stones. The distinctly painted winged putti, the depiction of the landscape and the dense vegetal decoration filling the frame in the upper and lower margin demonstrate noticeable similarities with the works of Giovanni Vendramin, a prominent representative of Paduan Renaissance miniature. Thefront page of the aforementioned incunable at Šibenik can be attributed to him; he may well have been helped by his workshop and collaborators. First and foremost, it ought to be mentioned that the decorative frame on one of the opening pages (c. 4v) in an Antiphonary at Ferrara features identical type of leaf decoration as the one that fills the upper and lower margin in the incunable at Šibenik. Here too, the playful putti wear classical sandals and necklaces made of red coral. Furthermore, putti with identical physiohnomies – wearing coral necklaces and classical sandals while holding ribbons in their hands – can be found on fol. 2r in the incunable of Marcus Tullius Cicero’s Orationes (Venice, Christophorus Valdarfer, 1471, Philadelphia, The Rosenbach Museum and Library, Inc 471ci). The landscape in which the putti are depictedis also arid and marked by a single dry tree rising from the ground covered with small stones. Identical putti can be seen on the cover of the incunable of Marcus Tullius Cicero’s, Tusculanae Quaestiones (Venice, N. Jenson, 1472, London, British Library, C.1c.10, fol. 1). The landscape is also depicted in the same way. An excellent comparative example can be found in the winged putti standing on an all’antica structure on the cover of the manuscript of Jacopo Camphora’s, De immortalitate animae (London, Brittish Library, MS Add. 22325) which is decorated with architectural forms. The left and the upper margins of the opening pages of Book I and Book III of Gaius Julius Caesar’s Commentariorvm de bello Gallico (Milan, Antonius Zarotus, 1477) are decorated with frames filled with white vine scrolls on red, green and blue background with white dots. The decoration extends beyond the ornamental frames and reaches into the gold initials G and C. Although the decorative frames were not completely finished, it can be ascertained that they were made with great skill and are of high quality. This frame type was frequently used by Giovanni Vendramin and the examples from Šibenik are very close to some of his works, especially those made for Jacopo Zeno, the Bishop of Padua (Padua, Biblioteca Capitolare).
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Sun, Dong-Sheng, Fa-Lin Lu, Yuan You, Chang-Yuan Chen, and Shi-Hai Dong. "Parity inversion property of the double ring-shaped oscillator in cylindrical coordinates." Modern Physics Letters A 30, no. 39 (December 7, 2015): 1550200. http://dx.doi.org/10.1142/s0217732315502004.
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Using the functional analysis method, we present the exact solutions of the double ring-shaped oscillator (DRSO) potential with certain parity in the cylindrical coordinates. Such a quantum system is separated to two differential equations, i.e. a one-dimensional harmonic oscillator plus an inverse square term and a two-dimensional harmonic oscillator plus an inverse square term. The key point is how to find the adapted symmetrical solutions of the one-dimensional harmonic oscillator plus an inverse square term at the singular point [Formula: see text]. The obtained results are compared with those in the spherical coordinates. We also explore intimate connections [Formula: see text] and [Formula: see text] by substituting [Formula: see text] and [Formula: see text].
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Datta, Prasun K., Lynda K. Hawkins, and Ramesh Gupta. "Presence of an intron in elongator methionine-tRNA of Halobacterium volcanii." Canadian Journal of Microbiology 35, no. 1 (January 1, 1989): 189–94. http://dx.doi.org/10.1139/m89-029.
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The gene for the elongator (internal) methionine transfer RNA [Formula: see text] in the archaebacterium Halobacterium volcanii contains a 75 base pair intron (intervening sequence) and lacks the 3′-terminal CCA sequence of the mature tRNA. There is a single copy of this gene in the genome and it is expressed. Northern hybridization experiments indicate that the precursor is processed to produce mature tRNA and a free intron species. A secondary structure of the transcript can be formed in which the anticodon stem of the tRNA is extended. Two symmetrically placed three-base bulge loops separated by a 4 base pair stem are present in this extension. The cleavage sites for the removal of the intron are placed between the middle and 3′ residues of these loops.Key words: archaebacteria, methionine-tRNA, intron, splicing.
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Dallman, M., and C. G. Fathman. "Type II collagen-reactive T cell clones from mice with collagen-induced arthritis." Journal of Immunology 135, no. 2 (August 1, 1985): 1113–18. http://dx.doi.org/10.4049/jimmunol.135.2.1113.
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Abstract Certain strains of mice develop a symmetrical polyarthritis after immunization with type II collagen. The incidence of arthritis after such immunization is variable. To study the arthritogenic potential of T cells reactive with type II collagen, we isolated draining lymph node cells from mice that had developed arthritis after immunization with bovine type II collagen. From these immune lymph node cells we were able to clone T cells reactive with type II collagen. Two separate sets of T cell clones were isolated. The first set reacted with either native bovine or native chick type II collagen, but did not react with type I collagen. The second set of T cell clones reacted with bovine type II collagen, but did not respond to either native chick type II collagen or type I collagen. These clones will be tested for their influence on the development of arthritis in vivo.
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Wiebelt, Alexandra. "Do symmetrical letter pairs affect readability?" Written Language and Literacy 7, no. 2 (March 22, 2005): 275–303. http://dx.doi.org/10.1075/wll.7.2.07wie.
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Our everyday experience shows that we have problems in recognizing objects which only differ in their symmetry properties (street signs with two arrows in different directions or mathematical signs such as 〈 and 〉). Perception is closely correlated with an inner comparison: the perceived object with its surrounding, the perceived object with former experience and so on. The brain has evolved different constancy abilities (e.g. colour constancy) and one of them is object constancy. This object constancy makes it possible to perceive an object regardless of its orientation in space. Symmetric letter pairs with different sound representations (such as 〈b〉 and 〈d〉) are, due to object constancy, typically identified as one object. This deficiency of distinctiveness should affect their readability. The above hypothesis was examined in many scripts. The result was that mature scripts (which usually developed for a long time) avoid these symmetric letter pairs (called extrinsic symmetry) by adding distinctive features such as serifs or different stroke thickness. On the other hand, if a writer is allowed to invent letter shapes freely, he makes use of extrinsic symmetrical letter pairs. This is supposed to have aesthetic reasons — letters are often perceived as a standing object or even as a “body” on a plane. It is therefore possible to statistically separate mature scripts which show up no extrinsic symmetry from invented scripts full of extrinsic symmetry. The runes are a writing system which does not quite fit in this widely proved distinction. They have developed from the Latin writing system (or a close relative of it) and have therefore inherited the avoidance of extrinsic symmetry. The reduction of the character set from 24 signs in the Old Futhark to 16 characters in the Younger Futhark is accompanied by a simplification of runic signs. During this period the runes develop a high degree of extrinsic symmetry. Moreover, the letter shapes are often related to different sound representations. These irregularities in usage may be caused by interference from the Latin writing system. The resulting lesser readability could have been one reason for the decline of the runes. This paper shows in many figures and graphs how symmetry emerges and under what circumstances it is used to create new letter shapes.
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Garg, Amit Kumar, Rajendra Kumar Tewari, and Neha Agrawal. "Prevalence of Three-Rooted Mandibular First Molars among Indians Using SCT." International Journal of Dentistry 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/183869.
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Undetected extra roots or root canals are a major reason for failure of endodontic treatment. Failure to recognize an extra distolingual (DL) root in mandibular first molar may lead to incomplete debridement of the root canal system and eventually treatment failure. Therefore, it is crucial that atypical anatomy is identified before and during dental treatment. Spiral computed tomography (SCT) images can show 3D images, and therefore much detail can be used when traditional methods prevent adequate endodontic treatment. The overall incidence of DL roots on the mandibular first molars was 6.40% for all patients and 5.00% for all teeth, respectively. The occurrence of DL roots on the right side and on the left side showed a statistically significant difference. The bilateral incidence of symmetrical distribution of DL roots was 56.25%. The DL root canal orifice was separated from DB canal orifice by2.79±0.34 mm, from the MB canal orifice by4.23±0.81 mm, and from the ML canal orifice by3.29±0.52 mm. The high prevalence of the DL root in permanent mandibular first molars among the Indian population by using SCT and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments.
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Wang, Jyh-Lih, I.-Fei Tsu, X. Y. Cai, R. J. Kelley, M. D. Vaudin, S. E. Babcock, and D. C. Larbalestier. "Electromagnetic and microstructural investigations of a naturally grown 8° [001] tilt bicrystal of Bi2Sr2CaCu208 + x." Journal of Materials Research 11, no. 4 (April 1996): 868–77. http://dx.doi.org/10.1557/jmr.1996.0108.
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Electromagnetic characterization and high resolution transmission electron microscopy have been conducted on the same 8° [001] symmetrical (010) tilt boundary in a naturally grown, bulk-scale bicrystal of Bi2Sr2CaCu2O8 + x (BSCCO-2212). The resistive transition showed excess resistance above and below Tc, suggesting some weak coupling at the boundary, but the inter- and intragranular voltage-current characteristics, irreversibility fields, and critical current density (Jc) values were very similar and characteristic of strongly coupled grains and grain boundary. The misorientation was accommodated by a set of partial dislocations with the Frank spacing of 1.9 nm. The dislocation cores appeared to be separated by relatively undistorted regions of crystal. The Jc, values at 25 K exceeded 103 A/cm2 in fields of several tesla, more than two orders of magnitude larger than that found earlier in [001] twist boundaries of BSCCO-2212. This result is consistent with the view that low angle [001] till boundaries play an important role for current transport in polycrystalline BSCCO tapes.
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Mikhaylin, A., M. A. Bandurin, and I. R. Akhmet’yanov. "Strength analysis of a cutting kinked curve plate with clamped free edges of a chisel type deep tiller." IOP Conference Series: Earth and Environmental Science 954, no. 1 (January 1, 2022): 012048. http://dx.doi.org/10.1088/1755-1315/954/1/012048.
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Abstract Currently existing chisel type deep tillers have a number of disadvantages. The authors propose a research of the strength of a deformer system element of an experimental chisel type deep tiller in the form of kinked plates with clamped-free edges. The present paper analyses the possibility of lengthening of the horizontal elements of the deep tiller shank deformer system without loss of their strength and significant change in their thickness. A mathematical model of a thin elastic homogeneous isotropic plate with clamped-free edges was used. A modified model of the kinked plate is proposed, which has not been investigated earlier. The presented problem is solved numerically. Calculation is performed in the first approximation for the stress-strain state of two isotropic fixed kinked plates with clamped medial edges, symmetrically fixed on a vertical shank, set obliquely to the vertical axis, having equal stiffness and constant cross-section along the entire length (volume objective). It is found that the reduction of the actual plate thickness by more than 1/3 of the design thickness is the most dangerous case. This result leads to failure of a separate fragment of the kinked plate. The proposed thickness of 2 mm does not immediately result in failure of a separate fragment of the part. The plate of the investigated form, made of C255 grade steel, will not provide sufficient strength of the part and its fixing on the deep tiller’s shank. The paper proves the possibility of using kinked plates of the given shape having a variable thickness profile.
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Iandiorio, C., and P. Salvini. "On the Formulation of an Elastic-Plastic Beam Model: the Pre-Integration Idea." IOP Conference Series: Materials Science and Engineering 1214, no. 1 (January 1, 2022): 012026. http://dx.doi.org/10.1088/1757-899x/1214/1/012026.
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Abstract This paper provides a formulation of an elastic-plastic beam model. The constitutive behaviour of material after elasticity limit is considered perfect plastic. Although this is not a general plastic behaviour, it allows to minimize mathematical difficulties to fulfil the idea: pre-integration trough the thickness extended to material non-linearity. Three types of deformation mechanisms are found: fully elastic, plasticization over only one side or both of sides. The complete kinematic set of equations are obtained, together with the analytical stress trends. Yield stress-continuity equations are used to separate the elastic and plastic domains. These domains define a quasi-state diagram; Allowing to associate the normal force and bending moment acting on the section to the elastic-plastic state within the section. Note that in the case of a rectangular section, the solution is given in a fully analytical form, otherwise the domains are solved numerical solutions. But these last, may be obtained once for all, for any one-symmetrical section.
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Wang, De-Yuan, Jia-Qin Liu, Xing Chen, Jian Yan, and Yu-Cheng Wu. "α-MnO2 Nanowires and Amino-Modified Reduced Graphene Oxide Hybrid Films for Constructing the Flexible High-Performance Symmetrical Supercapacitors." Nano 16, no. 07 (June 30, 2021): 2150080. http://dx.doi.org/10.1142/s1793292021500806.
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Graphene or its derivates are used as an electrode material for the fabrication of supercapacitors (SCs). However, graphene or its composites readily agglomerate or stack in water, which seriously imparts SC energy efficiency. Presently, we used a new composite using [Formula: see text]-MnO2 nanowires and nitrogen-doped reduced graphene oxide ([Formula: see text]-MnO2/NRGO) for the fabrication of electrodes required in symmetric SCs. Hydrothermally synthesized [Formula: see text]-MnO2 nanowires have a smooth surface, good dispersion, and a high length-to-width ratio. The formation of stable and densely networked structures and the synergy between NRGO and [Formula: see text]-MnO2 nanowires enable the [Formula: see text]-MnO2/NRGO film electrode to show a large area-specific capacitance (386.8[Formula: see text]mF[Formula: see text]cm[Formula: see text]) at 1[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] current density; the capacity retention is 62.4% when the current density increases from 1[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] to 10[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]. The flexible and symmetrical [Formula: see text]-MnO2/NRGO SC was assembled using [Formula: see text]-MnO2/NRGO film electrodes in 1 M Na2SO4 electrolyte with a cellulose paper separator, has good capacitance retention (94%), excellent Coulombic efficiency (99%) after 3000 cycles, and high energy density (28.22[Formula: see text][Formula: see text]Wh[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]) at 0.8[Formula: see text]mW[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] power density. The [Formula: see text]-MnO2 nanowires/NRGO hybrid film flexible and symmetrical SCs are characterized by high energy storage, good cycle life and Columbic efficiency, which offer promising applications in the portable and wearable electronics industry.
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Wang, Guangxue, Shengye Wang, Hao Li, Xiang Fu, and Wei Liu. "Comparative assessment of SAS, IDDES and hybrid filtering RANS/LES models based on second-moment closure." Advances in Mechanical Engineering 13, no. 6 (June 2021): 168781402110284. http://dx.doi.org/10.1177/16878140211028447.
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The question of which turbulence model is better for a given class of applications is always confusing for the CFD researchers and users. Comparative assessments of scale-adaptive simulation (SAS), improved delay detached-eddy simulation (IDDES) and other hybrid RANS/LES models based on eddy-viscosity models (EVMs) are thoroughly investigated. But how well they perform based on a second-moment closure needs to be answered. In this paper, a widely acclaimed Reynolds-stress model (RSM) in aeronautical engineering, SSG/LRR-[Formula: see text] model, is carried out. The relevant test cases include the NACA0012 airfoil stalled flows and turret separated flow. In order to make a more reasonable comparison, a seventh-order scheme WCNS-E8T7 is adopted to reduce the influence of the numerical dissipation and a symmetrical conservative metric method is used to ensure the robustness. By comparing with the relevant experimental data and the solutions by original SSG/LRR-[Formula: see text] model (etc. URANS), it shows that all of the three hybrid methods (SAS, IDDES and hybrid filtering methods) based on the SSG/LRR-[Formula: see text] model have a good ability to simulate unsteady turbulence. Among them, the IDDES correction has the most potential.
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Allum, J. H. J., and T. Ledin. "Recovery of vestibulo-ocular reflex-function in subjects with an acute unilateral peripheral vestibular deficit." Journal of Vestibular Research 9, no. 2 (April 1, 1999): 135–44. http://dx.doi.org/10.3233/ves-1999-9208.
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The centrally controlled compensation for a reduced horizontal vestibulo-ocular reflex (VOR) gain caused by a unilateral afferent deficit is usually studied following a selective surgical procedure which completely lesions the vestibular nerve or blocks the horizontal semicircular canal. The more common, unilateral, vestibular deficit encountered clinically, is a partial loss of peripheral vestibular function, following which peripheral recovery and/or central compensation may occur. We investigated changes of the VOR gain in response to a sudden, idiopathic, unilateral vestibular deficit in 64 subjects by examining the responses to low-frequency, whole-body, rotations about an earth vertical axis with different accelerations (5, 20 and 40 deg / sec 2 ) during in- and out-patient visits separated by 4 months in an attempt to identify changes brought about by peripheral recovery and by central compensation processes. Peripheral function was assumed to be measured by the response to caloric irrigation. It improved some 30% between the two visits. VOR responses for rotations towards the deficit side also improved between the two visits. Most improvement occurred for 20 deg / sec 2 accelerations. However, the correlation coefficient between rotation and caloric responses was always less than 0.6. Unlike caloric responses which improved over time, responses for rotations to the intact side did not change between the visits. For this reason, the majority of observed VOR rotation responses were nearly symmetrical at the time of the second visit, despite being below normal levels. These findings suggest that both peripheral recovery and central compensation processes help restore symmetrical VOR function for head rotations after a partial unilateral vestibular deficit. However the improvement of VOR response symmetry, particularly to slow ( < 40 deg / sec 2 ) accelerations, is largely independent of the recovery of peripheral sensitivity.
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Jones, G. H., J. A. F. Whitehorn, and S. M. Albini. "Ultrastructure of meiotic pairing in B chromosomes of Crepis capillaris. I. One-B and two-B pollen mother cells." Genome 32, no. 4 (August 1, 1989): 611–21. http://dx.doi.org/10.1139/g89-489.
Full textAbstract:
Chromosome pairing of a small metacentric B chromosome in Crepis capillaris has been studied by synaptonemal complex surface spreading of pollen mother cells containing either one or two B chromosomes. The B-chromosome axis, on average, represents about 8.7% of the axis length of the standard A-chromosome set, which is less than the corresponding values for DNA content (10.6%) and mitotic chromosome volume (13.6%). Single B chromosomes commonly undergo fold-back pairing to give a symmetrical hairpin loop, which supports earlier suggestions that this B chromosome is an isochromosome. Two B chromosomes may show interarm pairing, exclusively, or interchromosome pairing, exclusively, or combinations of the two. Near the centromeres pairing occurs preferentially between arms of the same chromosome, but chromosome ends show random association. Some B chromosomes show anomalous pairing configurations, which may reflect further orders of reverse repeats within arms or, alternatively, nonhomologous pairing. The period of B-chromosome pairing is confined almost exclusively to zygotene, when the standard A chromosomes are pairing, but within this period their pairing is delayed relative to the A set. Individual B chromosomes at zygotene contain from one to three separate synaptonemal complex segments. These are widely distributed within the chromosomes, mainly in distal and interstitial regions; pairing is delayed around the centromere.Key words: B chromosomes, isochromosomes, synaptonemal complex.
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Tang, Chaofei, Nurbol Luktarhan, and Yuxin Zhao. "An Efficient Intrusion Detection Method Based on LightGBM and Autoencoder." Symmetry 12, no. 9 (September 4, 2020): 1458. http://dx.doi.org/10.3390/sym12091458.
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Due to the insidious characteristics of network intrusion behaviors, developing an efficient intrusion detection system is still a big challenge, especially in the era of big data where the number of traffic and the dimension of each traffic feature are high. Because of the shortcomings of traditional common machine learning algorithms in network intrusion detection, such as insufficient accuracy, a network intrusion detection system based on LightGBM and autoencoder (AE) is proposed. The LightGBM-AE model proposed in this paper includes three steps: data preprocessing, feature selection, and classification. The LightGBM-AE model adopts the LightGBM algorithm for feature selection, and then uses an autoencoder for training and detection. When a set of data containing network intrusion behaviors are inputted into an autoencoder, there is a large reconstruction error between the original input data and the reconstructed data obtained by the autoencoder, which provides a basis for intrusion detection. According to the reconstruction error, an appropriate threshold is set to distinguish symmetrically between normal behavior and attack behavior. The experiment is carried out on the NSL-KDD dataset and implemented using Pytorch. In addition to autoencoder, variational autoencoder (VAE) and denoising autoencoder (DAE) are also used for intrusion detection and are compared with existing machine learning algorithms such as Decision Tree, Random Forest, KNN, GBDT, and XGBoost. The evaluation is carried out through classification evaluation indexes such as accuracy, precision, recall, F1-score. The experimental results show that the method can efficiently separate the attack behavior from normal behavior according to the reconstruction error. Compared with other methods, the effectiveness and superiority of this method are verified.
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Allagwail, Saad, Osman Gedik, and Javad Rahebi. "Face Recognition with Symmetrical Face Training Samples Based on Local Binary Patterns and the Gabor Filter." Symmetry 11, no. 2 (January 31, 2019): 157. http://dx.doi.org/10.3390/sym11020157.
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In the practical reality of face recognition applications, the human face can have only a limited number of training images. However, it is known that, in general, increasing the number of training images also increases the performance of face recognition systems. In this case, a new set of training samples can be generated from the original samples, using the symmetry property of the face. Although many face recognition methods have been proposed in the literature, a robust face recognition system is still a challenging task. In this paper, recognition performance was improved by using the property of face symmetry. Moreover, the effects of illumination and pose variations were reduced. A Two-Dimensional Discrete Wavelet Transform, based on the Local Binary Pattern, which is a new approach for face recognition using symmetry, has been presented. The method has three main stages, preprocessing, feature extraction, and classification. A Two-Dimensional Discrete Wavelet Transform with Single-Level and Gaussian Low-Pass Filter were used, separately, for preprocessing. The Local Binary Pattern, Gray Level Co-Occurrence Matrix, and the Gabor filter were used for feature extraction, and the Euclidean Distance was used for classification. The proposed method was implemented and evaluated using the Olivetti Research Laboratory (ORL) and Yale datasets. This study also examined the importance of the preprocessing stage in a face recognition system. The experimental results showed that the proposed method had a recognition accuracy of 100%, for both the ORL and Yale datasets, and these recognition rates were higher than the methods in the literature.
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Zhang, Xin, Huaxing Li, Kwing So Choi, and Longfei Song. "Coherent structures induced by dielectric barrier discharge plasma actuator." Modern Physics Letters B 31, no. 32 (November 19, 2017): 1850038. http://dx.doi.org/10.1142/s0217984918500380.
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The structures of a flow field induced by a plasma actuator were investigated experimentally in quiescent air using high-speed Particle Image Velocimetry (PIV) technology. The motivation behind was to figure out the flow control mechanism of the plasma technique. A symmetrical Dielectric Barrier Discharge (DBD) plasma actuator was mounted on the suction side of the SC (2)-0714 supercritical airfoil. The results demonstrated that the plasma jet had some coherent structures in the separated shear layer and these structures were linked to a dominant frequency of [Formula: see text] = 39 Hz when the peak-to-peak voltage of plasma actuator was 9.8 kV. The high speed PIV measurement of the induced airflow suggested that the plasma actuator could excite the flow instabilities which lead to production of the roll-up vortex. Analysis of transient results indicated that the roll-up vortices had the process of formation, movement, merging and breakdown. This could promote the entrainment effect of plasma actuator between the outside airflow and boundary layer flow, which is very important for flow control applications.
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Cui, Kaixuan, Hongmiao Pan, Jianwei Chen, Jia Liu, Yicong Zhao, Si Chen, Wenyan Zhang, Tian Xiao, and Long-Fei Wu. "A Novel Isolate of Spherical Multicellular Magnetotactic Prokaryotes Has Two Magnetosome Gene Clusters and Synthesizes Both Magnetite and Greigite Crystals." Microorganisms 10, no. 5 (April 28, 2022): 925. http://dx.doi.org/10.3390/microorganisms10050925.
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Multicellular magnetotactic prokaryotes (MMPs) are a unique group of magnetotactic bacteria that are composed of 10–100 individual cells and show coordinated swimming along magnetic field lines. MMPs produce nanometer-sized magnetite (Fe3O4) and/or greigite (Fe3S4) crystals—termed magnetosomes. Two types of magnetosome gene cluster (MGC) that regulate biomineralization of magnetite and greigite have been found. Here, we describe a dominant spherical MMP (sMMP) species collected from the intertidal sediments of Jinsha Bay, in the South China Sea. The sMMPs were 4.78 ± 0.67 μm in diameter, comprised 14–40 cells helical symmetrically, and contained bullet-shaped magnetite and irregularly shaped greigite magnetosomes. Two sets of MGCs, one putatively related to magnetite biomineralization and the other to greigite biomineralization, were identified in the genome of the sMMP, and two sets of paralogous proteins (Mam and Mad) that may function separately and independently in magnetosome biomineralization were found. Phylogenetic analysis indicated that the sMMPs were affiliated with Deltaproteobacteria. This is the first direct report of two types of magnetosomes and two sets of MGCs being detected in the same sMMP. The study provides new insights into the mechanism of biomineralization of magnetosomes in MMPs, and the evolutionary origin of MGCs.
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Lu, Bei, Nurbol Luktarhan, Chao Ding, and Wenhui Zhang. "ICLSTM: Encrypted Traffic Service Identification Based on Inception-LSTM Neural Network." Symmetry 13, no. 6 (June 17, 2021): 1080. http://dx.doi.org/10.3390/sym13061080.
Full textAbstract:
The wide application of encryption technology has made traffic classification gradually become a major challenge in the field of network security. Traditional methods such as machine learning, which rely heavily on feature engineering and others, can no longer fully meet the needs of encrypted traffic classification. Therefore, we propose an Inception-LSTM(ICLSTM) traffic classification method in this paper to achieve encrypted traffic service identification. This method converts traffic data into common gray images, and then uses the constructed ICLSTM neural network to extract key features and perform effective traffic classification. To alleviate the problem of category imbalance, different weight parameters are set for each category separately in the training phase to make it more symmetrical for different categories of encrypted traffic, and the identification effect is more balanced and reasonable. The method is validated on the public ISCX 2016 dataset, and the results of five classification experiments show that the accuracy of the method exceeds 98% for both regular encrypted traffic service identification and VPN encrypted traffic service identification. At the same time, this deep learning-based classification method also greatly simplifies the difficulty of traffic feature extraction work.
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Ghafur, Ala A., and Dana A. Hasan. "Petrophysical Properties of the Upper Qamchuqa Carbonate Reservoir through Well Log Evaluation in the Khabbaz Oilfield." UKH Journal of Science and Engineering 1, no. 1 (December 27, 2017): 72–88. http://dx.doi.org/10.25079/ukhjse.v1n1y2017.pp72-88.
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Khabbaz oilfield has a symmetrical subsurface anticline with a length of 20 km and a width of 4 km. Despite the fact that Khabbaz oilfield has a small size structure, it is known as one of the massive Oilfields in Iraq. The reservoirs of Khabbaz oilfield are produced by both Cretaceous and Tertiary rocks. The Upper Qamchuqa reservoir is the most productive reservoir of the Khabbaz oilfield with thickness ranges between 138 to 170 m. This formation is subdivided into two units, from the top is Unit A with a thickness of 67 m and from the bottom is Unit B with a thickness of 84.5 m. From a full set of log data of three wells (Kz-1, Kz-13 and Kz-14), the petrophysical properties of Khabbaz oilfield has been evaluated. The wireline log data includes gamma-ray log, sonic log, neutron log, density log and resistivity logs, both Rxo and Rt logs. This study revealed that Unit A represents the best reservoir characteristics where Unit A is subdivided into six reservoir subunits named (1-A, 2-A, 3-A, 4-A, 5-A and 6-A). They are separated by five non-reservoir subunits named 1-N, 2-N, 3-N, 4-N and 5-N. In addition to a less porous reservoir unit that is called Unit B, which has been divided into four reservoir subunits named 1-B, 2-B, 3-B and 4-B. These are separated by five non-reservoir units named 1-N, 2-N, 3-N, 4-N and 5-N. It has been recognized that both reservoir units A and B are clean formations and have minimum shale volume with high porosity in limestone and dolomite to dolomitic limestone lithology with high oil saturation and low water saturation. Based on the above reservoir characteristics it can be concluded that the reservoir units of the Khabbaz oilfield contain a massive commercial hydrocarbon accumulation.
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Winbow, Graham A. "Compressional and shear arrivals in a multipole sonic log." GEOPHYSICS 50, no. 7 (July 1985): 1119–26. http://dx.doi.org/10.1190/1.1441985.
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A sound source in a liquid‐filled borehole generates, among other excitations, compressional and shear waves in the rock which are detected in the fluid as refractions. It is practical to be able to separate the latter components. I show that this can always be achieved in principle by appropriately choosing the properties of the source. Solutions of the acoustic wave equation in the “far field” of the source are analyzed in detail. Suppose the source radiation depends upon the azimuthal angle η through some function F(η). The refracted waves are analyzed conveniently in terms of Fourier components [Formula: see text], where n and η are Fourier conjugates. For a source symmetrical about the axis of the borehole, as conventional sources are, [Formula: see text] vanishes except for n = 0. Our principal results concern the z dependence of the pressure radiation field in the drilling mud p (r, η, z) (using cylindrical polar coordinates). For a fixed n, as z → ∞, the refracted P‐wave is proportional to [Formula: see text] for n = 0, 1, … . The refracted S‐wave signal is proportional to [Formula: see text]. Thus, for an axially symmetric source, the P‐wave refraction generally dominates the S‐wave refraction as z → ∞. For an axially asymmetric source the S‐wave dominates the P‐wave. An example of an n = 1 source is a horizontally pointing dipole on the borehole axis. Higher order multipole sources also effectively produce nearly pure S‐wave signals in a borehole.
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Ye, Yu Ling. "Buoyancy Control for Low-Speed Under-Actuated AUVs." Applied Mechanics and Materials 644-650 (September 2014): 735–40. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.735.
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An engineering buoyancy control scheme was proposed to compensate the change of residual buoyancy for low-speed under-actuated AUVs. The buoyancy control system is made up of buoyancy controller and two sets of buoyancy control devices include: water tank, sea water pump, valve grouping, pipeline etc. Buoyancy control devices were configured to both head and tail part of the AUV symmetrical to its buoyant center. Depth control algorithm and buoyancy control algorithm were proposed separately. In the process of voyage at a constant depth, the real time speed, pitch angle and depth error were detected to evaluate the residual buoyancy indirectly, and then the real time buoyancy control was executed by pumping the water into or out of the tanks. The buoyancy control scheme was applied to the type of low-speed under-actuated AUV and simulation and experiments results show that the buoyancy control approach and the control laws are feasible and effective.
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Brandano, Marco, Laura Corda, Laura Tomassetti, and Davide Testa. "On the peritidal cycles and their diagenetic evolution in the Lower Jurassic carbonates of the Calcare Massiccio Formation (Central Apennines)." Geologica Carpathica 66, no. 5 (October 1, 2015): 393–407. http://dx.doi.org/10.1515/geoca-2015-0033.
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Abstract This paper shows the environmental changes and high-frequency cyclicity recorded by Lower Jurassic shallow-water carbonates known as the Calcare Massiccio Formation which crop out in the central Apennines of Italy. Three types of sedimentary cycle bounded by subaerial erosion have been recognized: Type I consists of a shallowing upward cycle with oncoidal floatstones to rudstones passing gradationally up into peloidal packstone alternating with cryptoalgal laminites and often bounded by desiccation cracks and pisolitic-peloidal wackestones indicating a period of subaerial exposure. Type II shows a symmetrical trend in terms of facies arrangement with peloidal packstones and cryptoalgal laminites present both at the base and in the upper portion of the cycle, separated by oncoidal floatstones to rudstones. Type III displays a shallowing upward trend with an initial erosion surface overlain by oncoidal floatstones to rudstones that, in turn, are capped by pisolitic-peloidal wackestones and desiccation sheet cracks. Sheet cracks at the top of cycles formed during the initial phase of subaerial exposure were successively enlarged by dissolution during prolonged subaerial exposure. The following sea-level fall produced dissolution cavities in subtidal facies, while the successive sea-level rise resulted in the precipitation of marine cements in dissolution cavities. Spectral analysis revealed six peaks, five of which are consistent with orbital cycles. While a tectonic control cannot be disregarded, the main signal recorded by the sedimentary succession points toward a main control related to orbital forcing. High frequency sea-level fluctuations also controlled diagenetic processes.
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Mackie, G. O. "Giant axons and control of jetting in the squid Loligo and the jellyfish Aglantha." Canadian Journal of Zoology 68, no. 4 (April 1, 1990): 799–805. http://dx.doi.org/10.1139/z90-115.
Full textAbstract:
Both Loligo and Aglantha have sets of giant axons arranged in a cascading series, which transmit impulses at high velocity and with short synaptic delays to the swimming muscles. The layout of the axons is such as to guarantee symmetrical, near-simultaneous contractions of all parts of the swimming muscles, necessary for effective jetting. The giant axons in both animals are multinucleate, syncytial structures. In both animals, the first-order giants receive a rich afferent innervation. Despite these similarities in the layout and properties of their giant axon systems, Loligo and Aglantha control their swimming muscles in very different ways. The most striking difference is that Loligo has separate fast and slow innervations as well as fast and slow muscles, whereas Aglantha has only one innervation and one set of muscles, but can produce two types of contraction by switching between rapidly propagated sodium spikes and slowly propagated calcium spikes in its giant motor axons. A second major difference emerging from recent investigations is that whereas Aglantha uses its fast impulse propagation system for a conventional, short-latency escape response, squid appear (at least in laboratory studies) to use their fast pathway merely to augment the power of contractions brought about by their slow innervation, making no use of the potential the giant fibres hold for short-latency, reflex escape behaviour.
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Smith, Martin R. "Mouthparts of the Burgess Shale fossils Odontogriphus and Wiwaxia : implications for the ancestral molluscan radula." Proceedings of the Royal Society B: Biological Sciences 279, no. 1745 (August 22, 2012): 4287–95. http://dx.doi.org/10.1098/rspb.2012.1577.
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The Middle Cambrian lophotrochozoans Odontogriphus omalus and Wiwaxia corrugata have been interpreted as stem-group members of either the Mollusca, the Annelida, or a group containing Mollusca + Annelida. The case for each classification rests on the organisms' unusual mouthparts, whose two to three tooth-rows resemble both the molluscan radula and the jaws of certain annelid worms. Despite their potential significance, these mouthparts have not previously been described in detail. This study examined the feeding apparatuses of over 300 specimens from the 505-million-year-old Burgess Shale, many of which were studied for the first time. Rather than denticulate plates, each tooth row comprises a single axial tooth that is flanked on each side by eight to 16 separate shoehorn-shaped teeth. Tooth rows sat on a grooved basal tongue, and two large lobes flanked the apparatus. New observations—the shape, distribution and articulation of the individual teeth, and the mouthparts' mode of growth—are incompatible with an annelid interpretation, instead supporting a classification in Mollusca. The ancestral molluscan radula is best reconstructed as unipartite with a symmetrical medial tooth, and Odontogriphus and Wiwaxia as grazing deposit-feeders.
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Rosmarion, Kerstin, Robert Tokhunts, and Robert Rothchild. "Diels-Alder Adducts of 3,6-Dibromophencyclone with Symmetrical 1,4-Disubstituted-Cis-2-Butenes: Comparisons with the Adduct of Phencyclone and N-Benzylmaleimide, and One-Dimensional and Two-Dimensional Nuclear Magnetic Resonance Studies and Ab Initio Structure Calculations." Applied Spectroscopy 59, no. 3 (March 2005): 366–75. http://dx.doi.org/10.1366/0003702053585408.
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Hindered Diels-Alder adducts have been prepared from 3,6-dibromophencyclone, 2, with cis-1,4-diacetoxy-2-butene, 3; cis-2-butene-1,4-diol, 4; and N-benzylmaleimide, 5. The adduct from the parent phencyclone, 1, with N-benzylmaleimide was prepared for comparison. One- and two-dimensional (1D and 2D) proton and carbon-13 NMR studies (at 7.05 tesla, ambient temperatures), including high-resolution COSY45 and HETCOR (XHCORR) chemical shift correlation spectra, were performed, allowing extensive rigorous assignments for protons and protonated carbons. Substantial anisotropic shielding was seen for the ortho protons of the N-benzyl group in the adducts of 5 with 1 or 2, with these aryl protons resonating at 6.25 ppm (CDCl3) for each adduct. The unsubstituted bridgehead phenyls of all four adducts showed slow exchange limit (SEL) 1H and 13C spectra. Greater shift dispersions for the bridgehead phenyl protons in the adducts from 5 relative to those from 3 or 4 suggested the role of the imide carbonyls for anisotropic contributions or for influences on adduct geometry. Ab initio geometry optimizations were performed at the Hartree-Fock level with the 6–31G* basis set (or the LACVP* basis set for the bromine-containing compounds) for each of the adducts. For the two adducts from benzylmaleimide, separate minima were located corresponding to conformers in which the benzyl group was directed into the adduct cavity ( syn) or out of the adduct cavity ( anti). Calculated energies and geometric parameters for the adducts are presented, and these suggested a significantly different structure for the dibromo diacetate adduct, in terms of general symmetry and bridgehead phenyl geometries, compared to the other adducts.
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Galvis, Daniel, Wei Wu, Richard L. Hyson, Frank Johnson, and Richard Bertram. "Interhemispheric dominance switching in a neural network model for birdsong." Journal of Neurophysiology 120, no. 3 (September 1, 2018): 1186–97. http://dx.doi.org/10.1152/jn.00153.2018.
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Male zebra finches produce a sequence-invariant set of syllables, separated by short inspiratory gaps. These songs are learned from an adult tutor and maintained throughout life, making them a tractable model system for learned, sequentially ordered behaviors, particularly speech production. Moreover, much is known about the cortical, thalamic, and brain stem areas involved in producing this behavior, with the premotor cortical nucleus HVC (proper name) being of primary importance. In a previous study, our group developed a behavioral neural network model for birdsong constrained by the structural connectivity of the song system, the signaling properties of individual neurons and circuits, and circuit-breaking behavioral studies. Here we describe a more computationally tractable model and use it to explain the behavioral effects of unilateral cooling and electrical stimulations of HVC on song production. The model demonstrates that interhemispheric switching of song control is sufficient to explain these results, consistent with the hypotheses proposed when the experiments were initially conducted. Finally, we use the model to make testable predictions that can be used to validate the model framework and explain the effects of other perturbations of the song system, such as unilateral ablations of the primary input and output nuclei of HVC. NEW & NOTEWORTHY In this report, we propose a two-hemisphere neural network model for the bilaterally symmetrical song system underlying birdsong in the male zebra finch. This model captures the behavioral effects of unilateral cooling and electrical stimulations of the premotor cortical nucleus HVC during song production, supporting the hypothesis of interhemispheric switching of song control. We use the model to make testable predictions regarding the behavioral effects of other unilateral perturbations to the song system.
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Sharin, Valery I. "Reciprocity in Intergenerational Mutual Aid: Students' Opinion." Vestnik Tomskogo gosudarstvennogo universiteta, no. 470 (2021): 108–15. http://dx.doi.org/10.17223/15617793/470/13.
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The article examines family social assistance relations. Researchers give ambiguous assessments of the nature of intergenerational relationships of mutual assistance between parents and their adult children who are students. Therefore, the research aim is to determine the nature of the relationship of family-related assistance in families with student children and the impact on family assistance of the type of (joint or separate) residence of children with parents. The methodological basis of the research was the developments of the theory of reciprocity by B. Malinovsky and K. Polanyi, the concept of social assistance by N. Luhmann, as well as works of leading foreign and Russian scholars. The research was conducted on the basis of a set of general scientific methods of systems analysis, generalization and systematization, comparison, and a questionnaire. The empirical basis of the research is a survey of 300 students and 12 individual semi-structured interviews of students of the Ural State University of Economics, held in 2020. The survey and interview data were analyzed to identify the nature and motivations of family assistance in families with student children, as well as the influence of the factor of joint or separate residence of children with parents. The study shows that the relationship of family assistance in families with student children is interdependent, symmetrical, and nonequivalent, that is, based on the principle of reciprocity. A person's motivation for family assistance forms under the influence of a situation objectively perceived as requiring the support of a family member and the potential helper's readiness to assist and the person helped to be assisted. Students' support for their parents is based on non-economic motives that reflect family solidarity, feelings of reciprocity and commitment. The factor of separate or joint residence of parents and student children affects the relationship of family assistance. Thus, in families where student children live together with their parents, a higher level of intergenerational mutual assistance is established. In these families, parents and student children are much more likely to help each other on a regular, permanent basis; children are more likely to provide parents with financial assistance, emotional and psychological support, assistance in caring for parents and in household management. Material, emotional and psychological support from parents is at a high level, regardless of the type of residence.
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Păvăloaia, Vasile-Daniel, Ionuț-Daniel Anastasiei, and Doina Fotache. "Social Media and E-mail Marketing Campaigns: Symmetry versus Convergence." Symmetry 12, no. 12 (November 25, 2020): 1940. http://dx.doi.org/10.3390/sym12121940.
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Companies use social business intelligence (SBI) to identify and collect strategically significant information from a wide range of publicly available data sources, such as social media (SM). This study is an SBI-driven analysis of a company operating in the insurance sector. It underlines the contribution of SBI technology to sustainable profitability of a company by using an optimized marketing campaign on Facebook, in symmetry with a traditional e-mail campaign. Starting from a campaign on SM, the study identified a client portfolio, processed data, and applied a set of statistical methods, such as the index and the statistical significance (T-test), which later enabled the authors to validate research hypotheses (RH), and led to relevant business decisions. The study outlines the preferences of the selected group of companies for the manner in which they run a marketing campaign on SM in symmetry with an e-mail-run campaign. Although the study focused on the practical field of insurance, the suggested model can be used by any company of any industry proving that BI technologies is the nexus of collecting and interpreting results that are essential, globally applicable, and lead to sustainable development of companies operating in the age of globalization. The results of the study prove that symmetrical unfolding (time and opportunity symmetry) of SM marketing campaigns, and using email, could lead to better results compared to two separate marketing campaigns. Moreover, the outcomes of both campaigns showed convergence on SBI platforms, which led to higher efficiency of management of preferences of campaign beneficiaries in the insurance sector.
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Neville, Helen, Janet L. Nicol, Andrew Barss, Kenneth I. Forster, and Merrill F. Garrett. "Syntactically Based Sentence Processing Classes: Evidence from Event-Related Brain Potentials." Journal of Cognitive Neuroscience 3, no. 2 (April 1991): 151–65. http://dx.doi.org/10.1162/jocn.1991.3.2.151.
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Theoretical considerations and diverse empirical data from clinical, psycholinguistic, and developmental studies suggest that language comprehension processes are decomposable into separate subsystems, including distinct systems for semantic and grammatical processing. Here we report that event-related potentials (ERPs) to syntactically well-formed but semantically anomalous sentences produced a pattern of brain activity that is distinct in timing and distribution from the patterns elicited by syntactically deviant sentences, and further, that different types of syntactic deviance produced distinct ERP patterns. Forty right-handed young adults read sentences presented at 2 words/sec while ERPs were recorded from over several positions between and within the hemispheres. Half of the sentences were semantically and grammatically acceptable and were controls for the remainder, which contained sentence medial words that violated (1) semantic expectations, (2) phrase structure rules, or (3) WH-movement constraints on Specificity and (4) Subjacency. As in prior research, the semantic anomalies produced a negative potential, N400, that was bilaterally distributed and was largest over posterior regions. The phrase structure violations enhanced the N125 response over anterior regions of the left hemisphere, and elicited a negative response (300-500 msec) over temporal and parietal regions of the left hemisphere. Violations of Specificity constraints produced a slow negative potential, evident by 125 msec, that was also largest over anterior regions of the left hemisphere. Violations of Subjacency constraints elicited a broadly and symmetrically distributed positivity that onset around 200 msec. The distinct timing and distribution of these effects provide biological support for theories that distinguish between these types of grammatical rules and constraints and more generally for the proposal that semantic and grammatical processes are distinct subsystems within the language faculty.
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Stephens, R. E., S. Oleszko-Szuts, and R. W. Linck. "Retention of ciliary ninefold structure after removal of microtubules." Journal of Cell Science 92, no. 3 (March 1, 1989): 391–402. http://dx.doi.org/10.1242/jcs.92.3.391.
Full textAbstract:
When axonemes of isolated gill cilia from the bay scallop Aequipecten irradians are heated at 45 degrees C for a minimum of 8 min in a 10 mM-Tris-HCl (pH 8), 1 mM-EDTA solution, nearly 80% of the tubulin is solubilized but most minor structural proteins are retained in a ninefold symmetrical configuration. This remnant consists of the junctional protofilaments, derived from outer doublet tubules, interconnected by nexin linkages, with radial spoke components still directed inwards. The remnant is of the same length as the original cilium, with the junctional protofilaments attached at the distal end to the ciliary tip and at the proximal end to the basal plate. Virtually identical fractionations can be achieved with blastula cilia isolated from both arctic and tropical sea-urchin embryos. The remnant is resistant to salt up to at least 1 M concentration, judged by the constancy of protein composition. Immunoblotting with antibodies against sea-urchin sperm flagellar tektins indicates that the tektins remain within the ciliary remnant, supporting their location within the junctional protofilament domain. The fractionation is inhibited by low pH, by magnesium or calcium ions in the millimolar range, and by monovalent ions at 10-fold higher concentrations. About a quarter of the total ciliary calmodulin is bound to the axoneme at micromolar calcium levels but most is released upon thermal fractionation. Polymerization of tubulin in the presence of the remnant results in singlet microtubules, separate from the remnant proper, suggesting that doublet formation may require coordinate co-assembly of tubulin with skeletal proteins. These observations demonstrate the existence of a fibrous skeleton in the axoneme, composed largely of ciliary tektins, nexin linkages, and other structural proteins.
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Musa, Abubakr E. S., Madyan A. Al-Shugaa, and Amin Al-Fakih. "Free–Free Beam Resting on Tensionless Elastic Foundation Subjected to Patch Load." Mathematics 10, no. 18 (September 9, 2022): 3271. http://dx.doi.org/10.3390/math10183271.
Full textAbstract:
Despite the popularity of a completely free beam resting on a tensionless foundation in the construction industry, the existing bending analysis solutions are limited to certain types of loads (mostly point and uniformly distributed loads); these are also quite complex for practicing engineers to handle. To overcome the associated complexity, a simple iterative procedure is developed in this study, which uses the Ritz method for the bending analysis of a free–free beam on a tensionless foundation subjected to a patched load. The Ritz method formulation is first presented with polynomials being used to approximate the beam deflection with unknown constants to be determined through minimization of the potential energy. To account for the tensionless action, the subgrade reaction is set to zero when the deflection is negative. The non-zero subgrade reaction zone is defined by αlL/2<x<αrL/2 where the coefficients αl and αr are to be determined iteratively. A numerical example is presented to illustrate the applicability of the proposed procedure for symmetrical and asymmetrical problems. The obtained results show high negative deflection, which proves the occurrence of separation between the beam and the supporting tensionless foundation. This location of negative deflection is called the lifted zone, while the point that separates between the negative and positive deflection is called the lift-off point. A parametric study is then performed to study the effect of the amount of load, stiffness of the beam, and the subgrade reaction on the length of the lifted zone. The results of the parametric study indicate that for the same beam stiffness to subgrade reaction modulus ratio (EI/k), the lift-off point remains the same and beams with lower stiffnesses or higher loads deflect more.
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PARMAN, Setyamartana, Affiani MACHMUDAH, and Vu Trieu MINH. "Comparative study on two-constant-amplitude input shapers to maneuver flexible satellite in small structural deflection." INCAS BULLETIN 14, no. 3 (September 9, 2022): 47–60. http://dx.doi.org/10.13111/2066-8201.2022.14.3.5.
Full textAbstract:
The satellite attitude maneuver using thrusters is studied in this paper. The satellite consists of a rigid main body and two symmetrical solar panels that are so large that their flexibility cannot be neglected. The finite element method is used to discretize the elastic motion of the solar panels. The solar panels are modeled as a set of rectangular plate elements and only out-of-plane displacement is taken into account. The satellite is controlled by a thruster in its main body, while there are no other control inputs on the solar panels. For the attitude maneuver, the roll, pitch and yaw torques generated by the on-off thruster are used and here can produce two different constant amplitudes. Then two types of fuel-efficient input shaping are formulated and applied to perform satellite attitude correction. The first type of input LHHL is preceded by the use of a small amplitude torque followed by a large amplitude one, while the sequence of torque applied to the second type of input HLLH is the opposite of the first input. The two types of inputs are applied separately to the same satellite. They managed to dampen the residual vibrations after reaching the desired attitude, but in achieving this condition the solar panels experienced considerable deflection during the transient response. Due to this, the effectiveness of the shaped inputs for maneuvering the satellites at small structural deflections of the solar panels during their transient responses is compared. The simulation results show that the use of the LHHL input shaper can minimize the structural deflection that occurs in the transient response during the satellite attitude maneuvering process.
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Yang, Jiayan, and Terrence M. Joyce. "Local and Equatorial Forcing of Seasonal Variations of the North Equatorial Countercurrent in the Atlantic Ocean." Journal of Physical Oceanography 36, no. 2 (February 1, 2006): 238–54. http://dx.doi.org/10.1175/jpo2848.1.
Full textAbstract:
Abstract The seasonal variation of the North Equatorial Countercurrent (NECC) in the tropical Atlantic Ocean is investigated by using a linear, one-layer reduced-gravity ocean model and by analyzing sea surface height (SSH) data from Ocean Topography Experiment (TOPEX)/Poseidon (T/P) altimeters. The T/P data indicate that the seasonal variability of the NECC geostrophic transport, between 3° and 10°N, is dominated by SSH changes in the southern flank of the current. Since the southern boundary of the NECC is located partially within the equatorial waveguide, the SSH variation there can be influenced considerably by the equatorial dynamics. Therefore, it is hypothesized that the wind stress forcing along the equator is the leading driver for the seasonal cycle of the NECC transport. The wind stress curl in the NECC region is an important but smaller contributor. This hypothesis is tested by several sensitivity experiments that are designed to separate the two forcing mechanisms. In the first sensitivity run, a wind stress field that has a zero curl is used to force the ocean model. The result shows that the NECC geostrophic transport retains most of its seasonal variability. The same happens in another experiment in which the seasonal wind stress is applied only within a narrow band along the equator outside the NECC range. To further demonstrate the role of equatorial waves, another experiment was run in which the wind stress in the Southern Hemisphere is altered so that the model excludes hemispherically symmetrical waves (Kelvin waves and odd-numbered meridional modes of equatorial Rossby waves) and instead excites only the antisymmetrical equatorial Rossby modes. The circulation in the northern tropical ocean, including the NECC, is affected considerably even though the local wind stress there remains unchanged. All these appear to support the hypothesis presented in this paper.
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Khanaychenko, A. N., and V. E. Giragosov. "Morphological features of the Black Sea turbot (Scophthalmus maeoticus) during the period of embryonic development." Marine Biological Journal 4, no. 4 (December 30, 2019): 62–81. http://dx.doi.org/10.21072/mbj.2019.04.4.06.
Full textAbstract:
Black Sea turbot (hereinafter BST), Scophthalmus maeoticus (Pallas, 1814), is a valuable fish for commercial fishery and promising object of industrial mariculture. Potential fecundity of BST is very high, 3–13 million eggs; however, survival of its progenies during early development in the sea is unpredictable and low (mortality is up to 90 %). In nature fertilized pelagic BST eggs rise to the sea surface in 2–3 hours; BST develop in upper waters being part of neuston till hatching. BST on its early stages of development could be considered the most vulnerable as the embryo is exposed to diverse adverse effects. The survival and physiological state of the larvae at hatching till exogenous feeding depend on the norm of morphological characteristics of the embryos during their development. Our aim was to study the norm of the changes in BST morphological characteristics during embryogenesis. Morphological analysis of the BST embryogenesis stages from fertilization till hatching on the basis of detailed study of intact embryos (> 2000 eggs) sampled from different experimental batches incubated under experimental conditions is presented. Digital photos and videos of alive eggs were taken with Canon PowerShot A720 using binocular microscope MBS-10 at magnification 8×4 and under light inverted microscope Nikon Eclipse TS100, equipped with analog camera, at magnification ×4, ×10, and ×40. The morphological features of embryogenesis in BST before and after fertilization, cleavage, blastulation, gastrulation, epiboly, and neurulation and until hatching are presented by photos with detailed description of transforming embryological structures. Fertilized pelagic BST eggs covered by transparent shell vary from (1.26 ± 0.14) to (1.31 ± 0.15) mm in diameter, have homogenously distributed yolk and a single round transparent oil drop of 0.20–0.21 mm, positioned at the top of the yolk. Scale of timing of morphological changes is presented in relative time units (as a time interval from fertilization until the emergence of morphological structure in percentage of the total duration of embryogenesis, % RT). Cleavage starts at 2.5 % RT. Cell division desynchronizes between the 6th and 7th cleavage, at 128 blastomeres. Yolk syncytial layer controlling processes of epiboly, cells differentiation, and morphogenesis is formed during the 10th–11th mitotic cycle (12 % RT, about 512–1024 cells). From the germ ring registered at 21 % RT, the embryonic shield develops (at 25 % RT), and organize formation of embryonic axis from 20 to 50 % epiboly (31 % RT). During 70–75 % epiboly (40–45 % RT), the neural keel is formed; notochord and optical primordia become visible; Kupffer’s vesicle emerges at the start of segmentation. Optic cups develop, and more than 20 somites are observed at the end of epiboly (49 % RT). By 60 % RT the Kupffer’s vesicle disappears in tail bud formed; lens placodes are formed in optic cups. Notochord vacuolization, myotomes formation, and tail growth are observed by 65 % RT. The caudal part of the body separates from the yolk by 70–75 % RT. About 80 % RT neuromuscular activity starts; heart beating initiates; free tail covers more than 60 % of the yolk; differentiating xantophores give a pinkish hue to the embryo. By 90–95 % RT eye cups with lenses; three symmetric otic capsules with otoliths, melanophores, and xantophores present in the embryo with 33–38 body somites; it performs jerky movements. Prior hatching, the egg shell becomes elastic, stretches, and breaks in the head area. Hatching occurs 114–94 hours after fertilization at +14…+16 °С. By hatching, all organs are formed in bilateral symmetrical BST larva (standard length is (2.53 ± 0.13) to (2.91 ± 0.10) mm), three auditory chambers with otoliths exist, eyes are non-pigmented, intestinal tract is closed; within 3–5 days it develops at the expense of yolk. Description of morphological changes in the BST embryo at norm of development could be used for elaboration of criteria of developing BST eggs both in natural environment and under cultivation conditions.
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Berezka, K. M., and O. M. Berezsky. "SYNTHESIS OF IMAGES-ORNAMENTS." Ukrainian Journal of Information Technology 3, no. 1 (2021): 56–62. http://dx.doi.org/10.23939/ujit2021.03.056.
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The article developed the mathematical model for the synthesis of ornamental images and implemented the software editor of ornamental images, based on symmetry theory. The paper shows the fundamental role of symmetry. It is analyzed that the symmetry theory methods are used in physics, chemistry, biology, and engineering. It was found that symmetry is based on transformation and storage. In addition, the symmetrical system is based on a set of invariants that are built according to certain rules. It is shown that the symmetry of borders and the symmetry of mesh ornaments are used in ornaments. The synthesis of ornamental images is considered on the example of Ukrainian folk embroidery. The contribution of foreign and domestic scientists to the development of the symmetry theory and synthesis of images is analyzed. It is indicated that Ukrainian folk embroidery is the valuable property of the cultural and material heritage of people and an important source of research. It is analyzed that there are more than 100 types of different embroidery techniques. The role of famous Ukrainian artists in the popularization and organization of Ukrainian folk embroidery museums is presented. It is investigated that embroidery is built from separate motives or from ornaments. Ornaments consist of sub-ornaments. A sub-ornament is a pattern consisting of rhythmically ordered identical elements (built on one group transformation). Subornaments are divided into reports. The report is called the minimum for the area of the area that can cover the sub-ornament, using only transfers. The report, in turn, is divided into even smaller particles: motive or elementary picture. It is found that in embroidery ornaments there are 7 groups of stripe and 12 - plan. Mathematical models of images-ornaments synthesis for groups of a strip and plan groups are developed. Mathematical models are given for ideal ornaments. If offsets of axes or centers of symmetries, it is necessary to adjust the coefficients of transformation matrices displacement. Samples of embroidered ornaments of the corresponding plane and stripe groups are provided. Editor of image-ornaments has been developed, which allows the synthesis of complex ornamental images based on analytical formulas of elementary picture, sub-ornament, and ornament. Examples of real and synthesized samples of Ukrainian folk embroidery are provided. The scientific novelty of the work lies in the development of mathematical models of ornaments on the basis of symmetry groups on the strip and the plane. The practical value of the work lies in the development of an image editor-ornaments.
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Sušanj Protić, Tea. "Renesansna kuća Moise u Cresu - rezultati konzervatorskih istraživanja 2011. godne." Ars Adriatica, no. 4 (January 1, 2014): 283. http://dx.doi.org/10.15291/ars.501.
Full textAbstract:
The Renaissance residential architecture in the town of Cres is represented by a small number of preserved houses (palazzetti) of the local nobility which are attributed to the established stone-cutting workshop grouped around master Francesco Marangonich, a Lombard stone-cutter who arrived at Cres from the building sites of Venice and introduced Renaissance stylistic elements on the Quarnero islands. The best-known Renaissance residential building at Cres is the Marcello-Petris house which was built in the 1510s for the Minister Provincial and Bishop, Friar Antun Marcello-Petris. The Renaissance houses of the Cres nobility are characterized by their relatively large size, ashlar masonry, and the strict rhythm of the decorated openings on the representative facades. One of such buildings is the Moise house, situated in the medieval centre of the town, at a prominent site where the two main streets of the time crossed. Documents from the archive of the Franciscan monastery at Cres witness that in 1441, “Ser Andrea Moisenich” exchanged a garden for the house of “Nobilis Ser Stefano de Petris”, who had the Petris palace built before 1405, meaning that the present-day Moise house might be identified with the old Petris palace. It features the coats of arms of these two families from the same period, and, therefore, it could have functioned as a shared residence of both families, which was frequently the case in Venice, for example, when it came to large palaces with two residential floors and two courtyards, which are both elements of the Moise house. The Moise house is the largest residential building of Renaissance Cres and, through its size, it can be compared to prominent examples of large palaces in Dalmatian towns. It has not been the subject of scholarly and expert research because of its many alterations, the relatively poor preservation of its original features, and the loss of its representative appearance, all of which means that its basic characteristics remained unknown. Conservation works revealed the layout of its ground plan and established that it was conceived as an emulation of the Venetian model, with a central hall and four lateral chambers. These features set the Moise house apart from other Renaissance residential buildings at Cres as the only one which adopted and displayed the high Renaissance symmetry of ground plan, which is also reflected on the representative facade. Analysis of the plaster samples taken from the walls has resulted in their stratigraphy, which confirms the hypothesis that all the walls of the central salone were painted a secco in the seventeenth century.The conservation works carried out on the representative facade unveiled the position of the Renaissance windows, which indicates that the articulating rhythm was two single-light windows – a double-light window – two single-light windows, which was corroborated by the discovery of the dressed inner window splays. Such an arrangement was common practice in Venetian Gothic residential architecture but, in the territory of present-day Croatia, it gained prominence only in the Renaissance, and the Moise house is the only example of this at Cres. The second floor of the Moise house repeated the plan of the first, which implies that originally there would have been two sumptuous storeys. The vaulted rooms on the ground floor did not communicate with one another but formed separate units in a direct relationship with the street or courtyards and it is likely that they had a utilitarian function as shops or storage spaces, having no vertical communication inside the house with the residential floors, which were connected by means of a single flight staircase. The building had two representative courtyards; the west one gave way to subsequent additions but it was recorded in the Land Registry as early as 1821. On the ground floor, the courtyard had a porch with two arches above which was a gallery with a balustrade, traces of which were discovered through test-probes in the floor. In the small east courtyard, the remains of the Renaissance porch, supported by the excellently carved pillars have been preserved, while in the floor under the staircase vault, a circular, finely-dressed stone opening belonging to a well was found; its well head is today located on the ground floor of the house. The two representative courtyards are an exception in the densely-knit urban texture of Cres, which places the Moise house in a wider context of Renaissance residential architecture in the Adriatic. Its local variety would be the positioning of the well under the vault of the staircase, which is characteristic of the vernacular architecture in medieval Cres. In comparison to other similar buildings at Cres, the Moise house is unique in that it is the only Renaissance house of the nobility with a regular plan; other Renaissance houses are of a mostly irregular quadrangular plan, including the most representative example of the palazzetto of the Cres nobility, the Marcello-Petris house. The Moise house is also the only building to have a symmetrical interior layout, which resonates with the symmetrical articulation of the representative facade, while in the case of the Marcello-Petris house, the consistent rhythm of the richly decorated windows in the south facade are a screen of sorts placed before the asymmetrically-arranged interior space.The construction of such a large building, at a dominant position in the medieval core can be explained by the role of the original commissioners, the Petris family, as the most prominent noble family at Cres, while the credit for the contemporary Renaissance organization of the interior – with the only extant example of a central representative hall in the Renaissance residential architecture at Cres – belongs to the builders, who had already demonstrated knowledge of contemporary Venetian models on the well-known portal of the collegiate church at Cres.The Moise house was marginalized in previous overviews of the Renaissance residential architecture because of the modest state of preservation of its Renaissance stone sculpture. The results of the conservation works, and the analysis of the spatial organization, ground plan, and location of this building, but also the analysis of historical records, should contribute to a clearer perception of the Moise house in the context of the fifteenth- and sixteenth-century residential architecture on the east Adriatic coast, and to a re-assessment of its diminished representative importance, the value which is hidden in the architectural structure, concept and context, within the frame of the urban texture of medieval Cres.
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Ebbesen, Klaus. "En højgruppe ved Kvindvad, Vestjylland." Kuml 53, no. 53 (October 24, 2004): 79–127. http://dx.doi.org/10.7146/kuml.v53i53.97371.
Full textAbstract:
A group of mounds near Kvindvad in Western Jutland The group of mounds in question is situated near Kvindvad in Western Jutland, a little more than ten kilometres from the town of Herning (Figs. 1-3). It is the only known group of mounds from the late Neolithic Age in Denmark. It consists of four mounds situated close together on the western side of a ridge. All the graves are dagger graves, and two of them are tiered graves.In mound no.1 (Figs. 4-6), a rectangular east-west orientated tiered grave was identified. It had been dug 0.6 metres into the subsoil and had a filling of earth and stones. The grave structure was covered by a stone paving. Grave A, which contained a flint dagger of type IA, was dug 0.4 metres into the subsoil. Grave B, also containing a flint dagger of type IA, was found at the bottom of grave A. This grave had faint traces of a wooden coffin.Mound 2 (Figs. 7-8) had been built over just one burial. This grave had a northeast-southwest orientation and was filled with stones. Colouring of the earth showed that the grave had contained a wooden coffin. The grave contained a flint for striking fire, recycled from a flint dagger of type Ix.Mound 3 (Figs. 9-10) had a diameter of 8 to 10 metres and a height of 0.25 to 0.30 metres. It had been constructed above a deep dagger grave with the faint remains of a wooden coffin. The grave was filled in with earth and stones. In the southwestern corner of the grave, a small heap of cremated bones and a pottery sherd were found a little above the bottom of the grave.Mound 4 (Figs. 11-15) had a diameter of 10 metres and a height of 0.25 to 3.0 metres. It had been constructed over a stone paving, which covered a tiered grave. The grave had a northwest-southeast orientation and was filled with stones. At a depth of 0.4 metres were the faint remains of a wooden coffin (grave A). It contained a flint dagger of type IA/B and a slate whetstone pendant. At the bottom of the grave (grave B) was a carefully made stone paving, on top of which yet another coffin had been resting. Two arrowheads with a concave base belong to this grave. The construction of the mounds corresponds to the older mounds known from the single grave culture. All four mounds contained so-called “deep dagger graves,” i.e. graves dug at least 1 metre into the subsoil. Almost all deep dagger graves are found in Northern and Central Jutland, with a marked concentration in Northwestern Jutland. Almost all deep dagger graves date from the late Neolithic Age A, with just a few dating from the late Neolithic Age B.The structures in two of the mounds are so-called tiered graves, which are characterized by having two burials in the same hole, one on top of the other. This is a very special burial custom, which occurs sporadically in the early and the late Neolithic Age across large parts of North and Central Europe.As is the case in the mounds at Kvindvad (Figs. 16-18), flint daggers are in general the most common grave goods in late Neolithic male graves. Slate pendants, on the other hand, occur only sporadically. The arrowheads with a concave base probably represent yet another weapon, i.e. the bow and arrow. These arrowheads are defined by a length not exceeding 8 cm, and by their concave base. This type occurs at the beginning of the late Neolithic Age and continues until period V of the Bronze Age (2400-600BC). So far, no one has succeeded in creating a typological and chronological classification of them. Generally, the arrows have a length of 2 to 6 cm and a thickness of 5 mm.Arrowheads with a concave base often occur in graves (some may even be the cause of death). Their numbers vary from one to twelve (Fig. 21). They occur in at least 57 late Neolithic closed graves. In 31 cases they occur together with flint daggers of type I, in seven cases in combination with daggers of type II.The burial custom of sending the dead to the grave with a bow and arrows thus seems to be primarily from the late Neolithic period A, but it continues into period B. In the later periods, the arrows occur more sporadically as grave goods. Graves containing arrows with a concave base show a clear concentration in Northern Jutland, where they occur mainly in the area surrounding the western Limfjord (Figs. 19-20).Ebbe Lomborg (1973 – cf. 1959 and 1968) divided the country into two geographic zones. Zone I comprised Northern Jutland and the islands, zone II comprised Southern Jutland and Schleswig-Holstein. The boundary between the two areas ran across Central Jutland.The grave types and burial customs described here occur across this boundary and in both zones. Moreover, neither the distribution nor the use of late Neolithic jewellery provides any evidence to support the traditional zone division.The same applies to grave forms and burial customs.The most frequently found burial custom in the late Neolithic Age is the burial of the dead in the old megalith graves. This burial custom is known from all over the country and throughout the age.Stone cists can be divided into at least two different types, which can be separated chronologically and geographically: 1. Small, north-south oriented stone cists (“stenkister” in Danish), which occur only in Northern Jutland during the early part of the late Neolithic Age. They probably originate from the early Neolithic stone cists, and were also built during the late Neolithic Age. 2. The so-called “Zealandic stone cists”, which are known only from Eastern Denmark, with a marked concentration in Northern Zealand. Almost all date from period C of the late Neolithic Age. These stone cists should be regarded as part of a larger context including Western Sweden and other areas of the Scandinavian Peninsula. They are connected to the late Western European megalith tradition, which became widespread in Western Sweden primarily during the end of the late Neolithic Age, but which also involved nearby parts of Denmark. It is noteworthy that these Western European contacts passed directly from Western Europe to Western Sweden – for the most part without passing through Denmark.Late Neolithic burial mounds are almost exclusively a Jutland phenomenon, although primary mound graves are rare. Among these, the deep dagger graves have an important position, as shown above.Among the “secondary” mound graves, the so-called “upper graves” are the most frequent form. In these, the coffin is surrounded by stone packing and is placed in the upper part of an old burial mound, usually an old single grave mound. The type is therefore almost exclusively found in the area where single grave mounds occur.Flat burials occur sporadically all over the country, with a characteristic concentration in Eastern Zealand.Late Neolithic cremation graves occur only randomly in Northern Jutland, and in an early part of the age.As neither the grave types nor the burial customs support Ebbe Lomborg’s zone grouping, this has to be rejected as regards the late Neolithic Age. As regards the early Bronze Age, the division of Denmark into zones has been justified by the fact that Southern Jutland had connections with the Sögel-Wohlde-circle and the western mound grave culture, whereas the rest of the country had direct contacts to Central Europe. The regional differences known from Northern Germany, as recognized from the bronze objects, thus applied in Denmark as well during the Bronze Age. In relation to the period prior to this they must be rejected.During the late Neolithic Age, Denmark consisted of small geographical areas, each with its own characteristics, just as was the case during the early and middle Neolithic Age. By the beginning of the late Neolithic Age, the area surrounding the Limfjord was the most important of these local areas. This is mainly expressed in the pottery, which is decorated in the Myrhøj style. It is possible that important elements of the late Neolithic culture came into existence in the area by the beginning of this age.The late Neolithic Age spans a very long period of time with a very rich and versatile source material. According to the C-14 datings, this age lasted for approximately 700 years, from c.2400 to c.1700 BC.The flint daggers which appear at the beginning of this age dominate. They are used as a stabbing weapon, as a stone for striking fire, and as a knife. The spearheads also represent a new weapon type. Other new items by the beginning of the age are spoon-shaped scrapers, and food knives. Crescent-shaped flint sickles (type I is symmetrical, type II is asymmetrical, i.e. they have their widest point near one of the tips) replace flint flake sickles. An important novelty by the early Neolithic Age is also the vertical loom and a general change in style of dress. By and large, the early Neolithic houses are unknown, and so it is impossible to determine whether the large longhouses from the late Neolithic Age also represent a novelty.The evidence suggests that the changes at the beginning of the late Neolithic Age happened very quickly, probably within a generation. After that, late Neolithic society was marked by conservatism that was extreme, even in the context of Stone Age peasant society. The changes during the nearly 700 year long period are few and insignificant.Denmark in the late Neolithic Age must be characterized as a tribal society. No decisive social differences are recognizable. The basic occupation was farming, primarily animal husbandry. Apart from this, a small late-Neolithic element known from the old kitchen middens from the Ertebølle culture provides indications of some sea hunting and fishing. The very large late-Neolithic houses indicate that all inhabitants of a settlement lived under the same roof.Most likely, power within the society lay in the hands of the old men, which would explain the extreme conservatism. Development was slow and kept within the framework already created during period A of the late Neolithic Age. Bronze Age phenomena from Western and Central Europe were adopted with huge delays and adapted to local traditions.These conditions only changed slowly during C/Per I of the late Neolithic Age. It was not until Bronze Age period II that the old pattern was broken and Danish society developed into a new society ruled by chieftains.Klaus EbbesenHørsholmTranslated by Annette Lerche Trolle
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Bogdan, Adrian Ionuț. "The Black Sea: A Geopolitical Space of Russian Thalassocratic Ambitions." Analele Universității din Oradea. Seria: Relații Internaționale și Studii Europene 14 (2022). http://dx.doi.org/10.58603/fcdh1903.
Full textAbstract:
Rarely has a maritime space played such an important role in geopolitics and the regional and international balance of power. The last twenty years have brought dramatic changes to the international system and demonstrated that the end of history predicted by Fukuyama in the 1990s has not come true. Although separated by almost 8000 km, the Seas around China and the Black Sea have reached a symmetrical position in the new confrontation between the Euro-Atlantic allies and the new Sino-Russian axis. Just as the seas in the east and south of China represent a front in the struggle to change the international system between Communist China and the US together with its Asian allies (Taiwan, Japan, and South Korea), so the Black Sea has become a geopolitical space of confrontation between Russia on one side and Europe and the US on the other. The research "The Black Sea: A Geopolitical Space of Russian Thalassocratic Ambitions" wants to analytically present how Moscow tried to achieve thalassocratic ambitions through its expansionist policy in the case of the Invasion of Georgia in 2008, the Annexation of Crimea in 2014, and with the Attack on Ukraine this year. In the center of these expansionist policies there have always been reasons such as the expansion of the Russian sphere of influence, and the blocking of the Euro-Atlantic enlargement, but to all this was also added, in a complementary way, a historical thalassocratic ambition of the Russian Federation.
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Harrow, Gabrielle L., John A. Lees, William P. Hanage, Marc Lipsitch, Jukka Corander, Caroline Colijn, and Nicholas J. Croucher. "Negative frequency-dependent selection and asymmetrical transformation stabilise multi-strain bacterial population structures." ISME Journal, January 6, 2021. http://dx.doi.org/10.1038/s41396-020-00867-w.
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AbstractStreptococcus pneumoniae can be divided into many strains, each a distinct set of isolates sharing similar core and accessory genomes, which co-circulate within the same hosts. Previous analyses suggested the short-term vaccine-associated dynamics of S. pneumoniae strains may be mediated through multi-locus negative frequency-dependent selection (NFDS), which maintains accessory loci at equilibrium frequencies. Long-term simulations demonstrated NFDS stabilised clonally-evolving multi-strain populations through preventing the loss of variation through drift, based on polymorphism frequencies, pairwise genetic distances and phylogenies. However, allowing symmetrical recombination between isolates evolving under multi-locus NFDS generated unstructured populations of diverse genotypes. Replication of the observed data improved when multi-locus NFDS was combined with recombination that was instead asymmetrical, favouring deletion of accessory loci over insertion. This combination separated populations into strains through outbreeding depression, resulting from recombinants with reduced accessory genomes having lower fitness than their parental genotypes. Although simplistic modelling of recombination likely limited these simulations’ ability to maintain some properties of genomic data as accurately as those lacking recombination, the combination of asymmetrical recombination and multi-locus NFDS could restore multi-strain population structures from randomised initial populations. As many bacteria inhibit insertions into their chromosomes, this combination may commonly underlie the co-existence of strains within a niche.
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Hassanine, Reda. "Trematodes from Red Sea fishes: Proneohelicometra aegyptensis gen. nov., sp. nov. (Opecoelidae Ozaki, 1925) and Neohypocreadium gibsoni sp. nov. (Lepocreadiidae Odhner, 1905)." Acta Parasitologica 51, no. 4 (January 1, 2006). http://dx.doi.org/10.2478/s11686-006-0038-0.
Full textAbstract:
AbstractSpecimens of the fishes Pterois volitans Linnaeus (Scorpaenidae) and Chaetodon auriga Forsskål (Chaetodontidae) were caught in the Red Sea off the coast of Sharm El-Sheikh, South Sinai, Egypt. Five (20%) and 20 (44%) of these fishes, respectively, were found to harbour intestinal trematodes. P. volitans was parasitised by Proneohelicometra aegyptensis gen. nov., sp. nov. (Opecoelidae) and C. auriga by Neohypocreadium gibsoni sp. nov. (Lepocreadiidae). Proneohelicometra gen. nov. is similar to Neohelicometra Siddiqi et Cable, 1960 which is the only opecoelid genus having caeca opening with separate ani and eggs with unipolar filaments, but differs significantly from it in having two lateral folds of body wall extending along the posterior third of body, an oral sucker smaller than the ventral sucker, a median cirrus sac not reaching the ventral sucker posteriorly and a median genital pore situating immediately posterior to the intestinal bifurcation. Neohypocreadium gibsoni sp. nov. is similar to the other four species of the genus, but is unique in having a distinctly pear-shaped body and a much smaller egg size, and differs significantly from each in several other characters: from N. longisaccatum, it differs in having a cirrus sac not reaching the testes and a pretesticular ovary; from N. dorsoporum in having an external seminal vesicle much shorter than the cirrus sac, a longer cirrus sac extending posteriorly to the level of the posterior margin of the ventral sucker and a pretesticular ovary; from N. chaetodoni in having a smaller body size, symmetrical testes, a longer cirrus sac extending posteriorly to the level of the posterior margin of the ventral sucker and a trilobed ovary; and from N. aegyptense in having a smaller body size, symmetrical testes, a longer cirrus sac extending posteriorly to the level of the posterior margin of the ventral sucker, a trilobed ovary and vitelline follicles terminating anteriorly at the level of oesophagus. Neohypocreadium Machida et Uchida, 1987 is briefly reviewed.
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Clayton, Alan M., and Thomas A. Duffey. "Protection Against Local Failure for Impulsively Loaded Vessels." Journal of Pressure Vessel Technology 137, no. 1 (September 15, 2014). http://dx.doi.org/10.1115/1.4027307.
Full textAbstract:
Significant changes have been incorporated in design limits for pressurized vessels in Section VIII, Division 3 of the ASME Code, starting in 2007. There is now a local damage-mechanics based strain-exhaustion limit as well as a separate global plastic collapse limit. In addition, Code Case 2564 (Sec. VIII, Div 3) has recently been approved to address impulsively loaded vessels. Recent studies (Nakamura, T., Kaguchi, H., and Kubo, S., 2000, “Failure Strain of Thin Cylindrical Vessel Subjected to Dynamic Internal Pressure,” Design and Analysis of Pressure Vessels and Piping, Vol. 399, R. Baliga, ed., pp. 47–54 and Duffey, T. A., 2011, “Plastic Instabilities in Spherical Vessels for Static and Dynamic Loading,” ASME J. Pressure Vessel Technol., 133(5), p. 051210) have shown that local strain limits play a particularly important role for these impulsively loaded vessels. In this paper, the new local strain-exhaustion procedure, originally intended for static-pressure-loaded vessels, is evaluated for adequacy in conservatively predicting failure for impulsively loaded vessels. Based upon symmetrically loaded cylindrical shell geometry, it is found that direct extension of the new local failure rules in the ASME Code to impulsively loaded vessels is unconservative. However, a hoop-strain local failure criterion predicts failures reasonably well.
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Mueller, Nadiya, Vanessa Trentzsch, Roland Grassme, Orlando Guntinas-Lichius, Gerd Fabian Volk, and Christoph Anders. "High-resolution surface electromyographic activities of facial muscles during mimic movements in healthy adults: A prospective observational study." Frontiers in Human Neuroscience 16 (December 12, 2022). http://dx.doi.org/10.3389/fnhum.2022.1029415.
Full textAbstract:
ObjectivesSurface electromyography (sEMG) is a standard tool in clinical routine and clinical or psychosocial experiments also including speech research and orthodontics to measure the activity of selected facial muscles to objectify facial movements during specific facial exercises or experiments with emotional expressions. Such muscle-specific approaches neglect that facial muscles act more as an interconnected network than as single facial muscles for specific movements. What is missing is an optimal sEMG setting allowing a synchronous measurement of the activity of all facial muscles as a whole.MethodsA total of 36 healthy adult participants (53% women, 18–67 years) were included. Electromyograms were recorded from both sides of the face using an arrangement of electrodes oriented by the underlying topography of the facial muscles (Fridlund scheme) and simultaneously by a geometric and symmetrical arrangement on the face (Kuramoto scheme). The participants performed a standard set of different facial movement tasks. Linear mixed-effects models and adjustment for multiple comparisons were used to evaluate differences between the facial movement tasks, separately for both applied schemes. Data analysis utilized sEMG amplitudes and also their maximum-normalized values to account for amplitude differences between the different facial movements.ResultsSurface electromyography activation characteristics showed systematic regional distribution patterns of facial muscle activation for both schemes with very low interindividual variability. The statistical significance to discriminate between the different sEMG patterns was good for both schemes (significant comparisons for sEMG amplitudes: 87.3%, both schemes, normalized values: 90.9%, Fridlund scheme, 94.5% Kuramoto scheme), but the Kuramoto scheme performed considerably superior.ConclusionFacial movement tasks evoke specific patterns in the complex network of facial muscles rather than activating single muscles. A geometric and symmetrical sEMG recording from the entire face seems to allow more specific detection of facial muscle activity patterns during facial movement tasks. Such sEMG patterns should be explored in more clinical and psychological experiments in the future.