Group Of Plates Research Articles

A Decorated Ivory Belt from Tilla Bulak, Southern Uzbekistan

Abstract The ivory belt-plate, one of two found in a burial at the site of Tilla Bulak, Uzbekistan, shows a battle scene between two groups of mounted warriors. It belongs to a small group of figural belt plates from the region and is dated iconographically to the 1st century BC / 1st century AD. The elephant tooth from which it was worked was more than 2000 years old at the time.

The transient response of floating elastic plates to wavemaker forcing in two dimensions

The time-dependent linear motion of a group of floating thin elastic plates is considered in a two-dimensional fluid domain. Forcing is provided by a wavemaker and the waves that transmit through the group of plates are partially reflected by a beach. Fourier transforms are used to relate the solutions in the time- and frequency-domain, where a solution is found using a combination of eigenfunction matching and transfer matrices. This allows reflections from the wavemaker and the beach to be included or excluded in a simple manner. Numerical results show that the frequency response of a single plate is significantly affected by the resonances introduced by the presence of the lateral boundaries. For a two-plate system the relative flexural response is found to be strongly dependent on plate spacing.

Weld interference detection based on airborne acoustical monitoring of the MIG/MAG process

The sound of the welding process is a consequence of the modulation in amplitude of the current for the voltage of the electric arc. Previous experiments demonstrated that an experienced welder has an absolute dependence on the acoustics in the control of the welding process. In this work, a new technique for the detection of welding defects is presented, based on the stability of the airborne acoustics of the MIG/MAG process for the short-circuit transfer mode. Statistical parameters of the sound pressure and of the sound pressure level were determined for welding without defects from multiple tests; an algorithm was developed from these results for detecting defects based on a moving window that moves through the statistical signals calculated from the acoustical process. Finally, a group of test plates with and without defects was tested; the algorithm based on the airborne acoustics of the developed process showed satisfactory results for the detection of defects.

Experimental Study of Ultimate Bearing Capacity of Hinged Plates with Different Configuration Hinge Joints

To study the role of vertical shear stress on the ultimate bearing capacity of hinge plates under fatigue loading, and different configurations of hinge joints on ultimate bearing capacity of hinged plates, three groups of hinged plate experiments were studied. Two groups of hinge plates with shallow hinge joint configurations were tested with static loading and fatigue loading respective, a group of hinge plates with deep hinge joint configurations were tested with fatigue loading directly. The ultimate bearing capacity analysis of hinge plates was carried out through mid-span deflection differences of hinged plates on both sides of hinge joints and transverse strains on top and bottom of hinge joints. Shown from the experimental results, for the hinge plates with shallow hinge joints, the ultimate bearing capacity under static load was 342.9kN, and under fatigue load was 340kN, but the ultimate bearing capacity under fatigue load of hinge plate with deep hinge joints was 610kN. Therefore, the vertical shear stress is not the main factor which cause the hinge joints destruction of hinge plates; hinge joints configurations, especially the depth of the hinge joints have great impact of ultimate bearing capacity of hinge plates; in the strengthen checking of hinge joints while hinge plates design, checking the vertical shear strength only is not comprehensive, various factors should be taken into account.

Local buckling analysis of pultruded FRP structural shapes subjected to eccentric compression

An analytical stability model for the local buckling of pultruded fiber reinforced polymer (FRP) structural shapes subjected to eccentric compression is presented. The model is based on considering each of these shapes as being composed of a group of orthotropic plates that are linked together. The differential equations that describe the buckling behavior of each of the plates comprising the shape were defined and solved using the Levy's solution. The presented model was used to conduct a parametric study to investigate the effect of the main parameters governing the local buckling behavior of such shapes.

Measurements of neutron total cross-sections and resonance parameters of erbium at the Pohang Neutron Facility

We measured neutron total cross-sections of natural erbium in the neutron energy region from 0.2 to 120 eV by using the neutron time-of-flight method at the Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled tantalum target with a water moderator, and a 12-m-long time-of-flight path. A 6Li–ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm was used as a neutron detector, and a group of high-purity natural erbium metallic plates with various thickness was used for the neutron transmission measurements. The present measurement was compared with the existing experimental and the evaluated data. The resonance parameters of 166Er, 167Er, 168Er, and 170Er in the neutron energy region below 120 eV were extracted from the transmission by using the multilevel R-matrix SAMMY code and were compared with the evaluated data from ENDF/B VII.0 and other previous reported results.

Redescription of Parotocinclus bahiensis (Miranda-Ribeiro, 1918) (Pisces, Ostariophysi, Loricariidae)

Microlepidogaster bahiensis Miranda-Ribeiro (1918), assigned to Parotocinclus Eigenmann & Eigenmann, 1889, by Garavello (1977), was described in a short and uninformative way which does not allow for its distinction from other species of Parotocinclus; besides, the two syntypes of the species are regarded as lost. For these reasons a neotype is herein designated and a detailed description of the species is presented based on topotypes. The species is characterized by the combination of the following features: scapular bridge almost completely exposed ventrally, arrector fossae, when present, small or very reduced; abdomen covered by 5–7 wide lateral plates on each side and very small platelets in between, leaving abundant naked areas surrounding them; a small group of larger plates in front of anus; caudal peduncle ellipsoid in cross section; total plates in median series 21–23; longitudinal series with 23–26 plates; 18–29 teeth on premaxillary and 12–24 on dentary; it can also be distinguished by its characteristic caudal-fin color pattern. Features that allow us to assign the species to Parotocinclus and a hypothesis about its relationships with other species of the genus are also presented.

Detección de perturbaciones en soldadura basado en el monitoreo de la acústica aerotransportada del proceso MIG / MAG

El sonido del proceso de soldadura es una consecuencia de la modulación en amplitud de la corriente por la tensión del arco. Experimentaciones pasadas demostraron que un soldador experimentado tiene una dependencia absoluta de la acústica en el control del proceso de soldadura. En este trabajo se presenta una nueva técnica de detección de defectos de soldadura basada en la estabilidad de la acústica aerotransportada del proceso MIG/MAG para el modo de transferencia por corto-circuito. Se determinaron parámetros estadísticos de la presión acústica generada por el arco eléctrico del proceso de soldadura MIG/MAG en el modo de transferencia por corto-circuito a partir de múltiples soldaduras en posición plana sobre cuerpos de ensayo libres de defectos. Con estos resultados se desarrollo un algoritmo de detección de defectos basado en una ventana móvil que se desplaza a través de las señales estadísticas calculadas a partir de la acústica del proceso. Finalmente sobre un conjunto de cuerpos de prueba con y sin defectos fueron hechas soldaduras en posición plana para la evaluación del desempeño de la técnica de detección de defectos propuesta. El algoritmo de detección de defectos basado en la acústica aerotransportada del proceso, mostró resultados satisfactorios.

G.J.R. Cook, M.N. Maisey, K.E. Britton and V. Chengazi, (eds.): Clinical nuclear medicine, 4th edition.

Developments over recent years have forced workers in the field of nuclear medicine to update approaches, guidelines and clinical applications for PET and other aspects of molecular imaging regularly. In the fourth edition of Clinical Nuclear Medicine, the editors have done a great job, as the book presents topics of current importance that are relevant to the practising clinician with a problem-oriented approach. This book contains 21 chapters, 879 pages and a well-organised index and is subdivided into three large sections. All chapters are written by highly esteemed colleagues, which is reflected in the excellent quality of the presentations and illustrations. Section A is dedicated to clinical topics, such as molecular imaging, principles of radionuclide therapy, imaging of infection and inflammation, paediatric imaging and sentinel node imaging. In addition to basic principles, each chapter nicely presents protocols and clinical studies. Furthermore, the tables are complete and provide a clear overview of imaging and treatment-related aspects, such as causes of false interpretations on PET scans, response criteria, biological applications of tracers, etc. Section B is dedicated to clinical systems, such as diseases of the head and neck, diseases of the cardiovascular system, diseases of the gastrointestinal tract and endocrine disorders. Most of the chapters are richly illustrated with black and white images or figures, while colour plates are provided for some topics. The position of these colour plates in the book is somewhat surprising, as the first group of plates is right in the middle of the chapter on cardiovascular diseases (between pp. 168 and 169) and the second group of plates, between salivary pathology and endocrine diseases (between pp. 487 and 488). It would have been more sophisticated to put these plates immediately before or after the index. Nevertheless, the quality of these illustrations is excellent. In the third section, some technical topics are discussed, as is nowadays inevitable in books dedicated to nuclear medicine. The first chapter in this part is related to pitfalls and artefacts in PET imaging, and the second addresses diagnostic accuracy and cost-effectiveness; the author has provided an informative description ranging from basic statistical and epidemiological aspects to cost-benefit analysis. In chapter 20, the authors present a complete overview on radionuclides, with emphasis on interactions and reactions and the development of new radiopharmaceuticals for SPECT and PET. In the last chapter, technology and instrumentation are clearly described. Solid state and other detectors are summarised, and image registration and reconstruction techniques are presented and illustrated with good-quality figures. The editors have stated that this book will be invaluable not only to practising and trainee nuclear medicine physicians and radiologists, but also to other groups of clinicians using nuclear medicine methods to investigate their patients, particularly cardiologists and oncologists. In my opinion, they have succeeded in their aim by combining easily readable chapters, high-quality figures and images and complete tables and reference lists. Therefore, this book is highly recommended, especially as a textbook for those who are involved in clinical nuclear medicine. Congratulations are due to the editors of and contributors to this work.

REDUCTION OF SCOUR AROUND A BRIDGE PIER BY MULTIPLE COLLAR PLATES

ABSTRACT Scour around a bridge pier is one of the major possible causes of the hydraulic failures of a bridge. A typical sediment-water-structure interaction at the upstream junction of the bridge pier initiates a vortex system, the primary vortex of which is responsible for local scour around the pier. The growth of the primary vortex can be arrested by retaining it on a rigid surface as on a collar plate. A number of experiments covering various sizes of collar plates were carried out in an effort to minimize scour around a bridge pier. A collar plate of size three times the diameter of the circular pier, D or larger when placed at the average bed level assures 100% scour reduction while a collar plate of size 2D placed 0.1D below the bed does not allow scour depth to go beyond it. Anticipating degradation of general bed level, a group of multiple collar plates of smaller size were employed at the laboratory scale to reduce the scour considerably. A group of three collar plates of size 1,5D having an inter-plate spacing Cs of D/6 with the middle plate placed at the average bed level reduces scour by 83% in comparison to the scour depth of an unprotected pier. The composite device, apart from being axis symmetric, is highly suited to degrading river beds.

Storage Phosphor Plates: How Durable are they as a Digital Dental Radiographic System?

The aim of this in vitro investigation was to evaluate the durability of storage phosphor plates (SPPs) as a digital dental imaging system and to detect the factors that may contribute to possible reduced durability. A total of 140 new SPPs were divided into groups and exposed to the effects of the various handling steps during the image acquisition. An additional group of plates joined the existing plates in the Radiology Clinic and tested the additive effect of all these factors plus the effect of positioning the plates in a patient's mouth. The images resulting from these SPPs were regularly evaluated for the appearance of scratches as a sign of wear and rated by an oral radiologist using a 6 point scale. Although the manufacturer claims the SPPs can be used indefinitely, we found 95% of our plates were rendered non-diagnostic after only 50 uses. The manufacturer's claim for indefinite use of the SPPs seems to be questionable.

Multilayer Primary Epithelial Cell Culture from Bovine Conjunctiva as a Model for in vitro Toxicity Tests

Objective: The purpose of this study was to obtain a primary cell culture of bovine origin similar to the conjunctiva in terms of morphology and cell types, which could be of use for in vitro toxicity studies. Methods: After separation from the stroma by enzymatic treatment, conjunctival epithelial cells were dissociated and plated onto collagen-coated Transwell^® filters (1.13 cm² area). One group of plates was maintained in immersion and another was cultured under air-lifted conditions. Anti-epithelial keratin antibodies (AE1/AE3, K4) and antidesmoplakin 1 and 2 were used to characterize the cells by indirect immunofluorescence. The cell layer was examined after histological processing of the Transwell filter. Ultrastructural analysis was carried out by scanning electron microscopy (SEM). The bioelectric parameters transepithelial electrical resistance (TEER), potential difference (PD), short circuit current and paracellular permeability profile of carboxyfluorescein were monitored as indices of the functional characteristics of these cultures. Cytotoxicity was evaluated on morphological and functional (TEER) grounds after treating the cultures with several test substances. Results: Morphological studies showed pure and homogeneous cell cultures. In the SEM analysis, we observed contiguous polygonal cells with numerous short microvilli, a characteristic proportion of light, medium and dark cells and a sparse population of rounded PAS-positive cells, i.e. resembling goblet cells. Air-lifted cultures also showed a tissue-like cellular organization (8–9 layers). Immersion cultures reached a maximum TEER value of around 2.95 kΩ·cm² 7 days after plating while in air-lifted cultures TEER peaked up to 5.59 kΩ·cm² 11 days after plating. With regard to the use of bovine conjunctival epithelial cells (BCECs) for cytotoxicity screening, the system responded finely to the insults and yielded morphological and functional results in accordance with data obtained in vivo. Conclusions: BCECs reproduce cell morphology and differentiation of the original tissue and should prove a useful tool for initial studies of drug toxicity.

Atomic force microscope study of stress-induced martensite formation and its reverse transformation in a thermomechanically treated Fe–Mn–Si–Cr–Ni alloy

Consecutive observations of the stress-induced martensite formation and its reversion by atomic force microscopy have been carried out for the fcc/hcp transformation in the thermomechanically treated sample of an Fe–Mn–Si–Cr–Ni shape memory alloy. It is found that thin martensite plates of 0.1–0.2 μm thickness, which are the same martensite variant on the same habit plane, are formed one after another at the immediate neighbor of the existing martensite plate. These martensite plates make a group of several plates within the width of 1–2 μm. This formation mode of martensite is compared with those martensite plates observed by high resolution microscopy and optical microscopy and it is concluded that the basic mode of the stress-induced transformation is that each martensite plate is induced to relieve the shape strain of the existing martensite plate for all the observed magnifications ranging from several hundreds to several millions. The first martensite plate formation is presumed to occur at the pre-existing stacking fault in austenite. In the reverse transformation on heating, it is likely that each martensite plate is reverse-transformed one after another by reverse movement of the Shockley partial dislocations residing at the tip of the plate. This seems to be true for every range of the observable magnification from namometres to microns. Such a reverse transformation mode ensures a good shape memory effect in Fe–Mn–Si-based shape memory alloys.

押し剥離作用を考慮した合成梁の実用式について

Some composite beam problem requires the different boundary conditions in each beam. The degree of freedom in each node becomes three by permitting split-off action, and it becomes possible to treat the boundary conditions independently for the each beam terminal. The author develops new composite beam theory permitted this action and shows the effectivity of this theory by applying it to the problem of the composite floor slab smeared with the flexural cracks in the tension zone of the concrete portion. The solution of this illustrative problem also gives the explanation of the phenomenon of the observed poor composite action when we use some group of steel deck plates.

Plate Anchor Groups Pulled Vertically in Sand

Results are presented of model-scale vertical pulling tests carried out on groups of square anchor plates in row and square configurations. The tests were carried out at a single depth of embedment, which ensured shallow anchor behavior in the sand placed at a constant dry density. It is shown that the load-displacement relationships for all groups may be reduced to a common curve. The load-carrying capacity of a group of anchor plates increases with the spacing between the individual plates up to a limiting critical value, and it is demonstrated how the results of pulling tests with different numbers of plates in a group may be described in a simple unifying manner. A possible means of predicting the effect of interaction on the uplift capacity of both modeland full-scale anchors in row configurations is suggested. For laboratory tests on a linear group of five anchors, it is shown that the end anchors attain the highest loads but all loads converge to an equal value as the spacing increases to the critical value.

Three Shakespearean Prints

A RMADO'S PHRASE IN LOVE'S LABOR'S LOST (5.1.89),' twice repeated by Holofernes (11. 91 and 119-20), is taken by most commentators to be a deliberate joke, underlined, as Eric Partridge points out, by the schoolmaster's admiration of the expression as well cull'd (1. 93).2 Partridge goes on to suggest that there is, perhaps, an allusion to afternoon dalliance, which to many readers probably seems rather strained, even if they remember Malvolio's preposterous fantasy about a daybed. But Armado's mind is running on more than shows and pageants, and I can perhaps offer some support for Partridge's intuition. Holofernes's answer to Armado's request is the show of the Nine Worthies, a subject that was a favorite theme not only for pageants, street shows, and entries from the Middle Ages onward but also for wall paintings, tapestries, and-from an early date following their invention-mechanically reproduced prints. As a motif, the Nine Worthies-with their matching Nine Women Worthies or Nine Modern Worthies-formed part of a popular genre of series prints, in which several related subjects were presented in a numbered group of cuts or plates, often symbolically presenting the passage of time. Typical secular themes were the Four Seasons, the Four Elements, the Five Senses, the Seven Planets, the Seven Liberal Arts and Sciences, the Seven (or Three, Four, Nine, Ten, or Twelve) Ages of Man, the Nine Muses, the Twelve Months (or the twelve celestial signs [5.2.797]), and so on. The series to which Armado alludes is the Four Parts of the Day: Morning, Noon, Evening, and Night. I believe that Shakespeare would have known this visual tradition;3 Figure 1 represents this

Tethys reconstructed : plates, continental fragments and their Boundaries since 260 Ma from Central America to South-eastern Asia.

This paper describes the evolution of the former Tethys ocean in terms of successive positions of the involved plates, their boundaries, and the oceanic and continental elements they bore. Most of the past positions for the major continents are obtained from published data on the kinematics of the Atlantic and Indian oceans. As they do not cover the complete time span and area under study, additional solutions for the missing parts are proposed on the basis of paleomagnetic and geologic data. A revised reconstruction of Eastern Gondwana and a reappraisal of the early history of the Indian ocean is presented, as well as a discussion of the Pangea megashear concept which applies to the relations between Gondawa and Laurussia during latest Palaeozoic to Mid-Triassic times. Past positions of continental blocks, basins and associated plate boundaries within the now disappeared Tethys ocean, are determined through the kinematic inversion of the Alpine chains interpreted in terms of break-up, oceanic spreading and drift, subduction and collision. A quantitative solution is obtained by associating Eulerian rotation parameters to any relative displacement, computing their combination, then adjusting until a complete coherency through time and space is obtained. Our method puts emphasis on the former positions of the plate boundaries in the Tethys, and stresses the drastically different organisation of Tethys west and east of a fundamental triple junction located in its Mediterranean part. A symmetric Atlantic part of Tethys, governed by a mid-ocean diverging boundary, was thus linked eastwards to an asymmetric “Transit” part of Tethys where southern diverging boundaries and northern converging boundaries defined a Transit plate (or group of plates). Besides several reorganisations through southward shift of these boundaries, the successive (or coeval) transit plates systematically exhibited the same north-south asymmetry responsible for the northward migration of the various continental blocks they carried, which were successively detached from Gondwana to become accreted to Eurasia. The transit process, while an essential element of the Tethyan tectonic pattern, was not restricted to lifetime of Tethys, as it is still active nowadays and was already active during the Palaeozoic. Nevertheless, its association with the Atlantic Tethys diverging boundary is typical for the lifetime of Tethys, both constituting a “Tethys plate pattern”, in opposition to the present-day and to Hercynian “Anti-Tethys plate pattern” where a converging boundary is and was associated with the transit plate system. Two pre-eminent tectonic events, the Late Triassic switchover from the Anti-Tethys pattern to the Tethys pattern, and the Late Cretaceous switchover back to the Anti-Tethys pattern, decided birth and death of the Tethys ocean.

Science and the Past ed. by Sheridan Bowman

TECHNOLOGY AND CULTURE Book Reviews 413 traces the professionalization of the sciences as it affected, and was affected by, the establishment and growth of early museums. The professionalization of the sciences is central to Orosz’s argument as it becomes the barometer for understanding the tension between pop­ ular education and elite scholarship. The first museums after the revolution organized around a scientific theme to gain legitimacy as public institutions of education and announce the pride of a free nation. During the subsequent periods discussed, the sciences were used as bastions against the masses, or mediums to outreach to the public. Orosz’s vast use of primary sources and tireless discussion of individuals offer historians of science and technology a refreshing view of the shift from amateurism to professionalism in the sciences during the first half of the 19th century. Although the importance of the book is not diminished, Curators and Culture suffers from several lapses of analysis. Orosz’s periodiza­ tion is too simplistic and glosses over the subtleties of cultural change and the effects of that change on museums. His conclusion that by 1870 the form of the modern museum was in place seems precocious. As scholars such as Arthur Molella and Neil Harris have shown, the modern, cosmopolitan museum was far from complete in 1870. The conclusion is faulty because of Orosz’s preoccupation with the tension between popular education and scientific research. His own evidence seems to support a contradictory argument that popular education and research did not gain predominance over one another at different periods of time but were coexistent with one another at all times. Finally, Orosz’s refutation of the democratic criticism and the professional criticism is not completely convincing. Indeed, his evi­ dence shows that early museums deserve these derogatory labels as much as they should he studied as serious institutions. This kind of complex analysis is what is missing in Curators and Culture. Neverthe­ less, Orosz has written an important book that will challenge histori­ ans of American museums to look more carefully at early institutions, their proprietors, and the culture that created them. Michael FitzGibbon Mr. FitzGibbon is a doctoral candidate in the Social Policy, History and Museum Studies Program at Case Western Reserve University. Science and the Past. Edited by Sheridan Bowman. Toronto: University of Toronto Press, 1991. Pp. 192; illustrations, glossary, references, index. $40.00. The title of this book is at once too broad and too narrow, but an attempt to repair it would lead to a 19th-century-style subtitle on the order of “Being an account of the application of science and technol­ 414 Book Reviews TECHNOLOGY AND CULTURE ogy to the analysis, conservation, and management of the collections in the British Museum, with especial reference to the provenance, production, and cultural context of sundry classes of artifact.” Those who have enjoyed Cyril Stanley Smith’s essays will find Science and the Past equally evocative, though the book’s broader focus includes ceramics and glass in addition to metal objects and metallurgy. The essays are of consistently high quality and go beyond the straightfor­ ward description of methods and results to comment and speculate about the artifacts and artisans themselves. Copious, pertinent, and well-labeled black-and-white illustrations complement the text, and a group of color plates further enhances both the educational and aesthetic content. An informative glossary provides clear, concise descriptions of the analytical tools, from atomic absorption spectro­ photometry to X-ray radiography. Each essay closes with suggestions for further reading and a full scholarly apparatus of references. Readers of this journal will be struck by the fact that the questions asked by the British Museum’s Department of Scientific Research are those of interest to historians of technology: How were these things made? Where did the materials come from? Who were the artificers, and what were their motives? What was their place, and the place of their product, in the fabric of their societies? That these questions are asked in the context of art history reminds us of the close relationship between art and technology, so evident in much 20th-century work and here once again shown to extend seamlessly into...

Shape memory alloys: from high-resolution thermal analysis to predictive modelling and simulation

Using high-resolution automatised equipment (close to 0.001 N, 0.1 μm and 0.005 K), detailed observations can be made of the surfaces stress, strain and temperature (σ, ϵ, T) of Cu-Zn-Al shape memory alloys. The analysis of the experimental curves allows a model of the behaviour of the alloy to be formulated. The model deals with a group of independent plates with a limited maximum growth and it separates the total friction into two parts: the nucleation of the domains of martensite or austenite (parent phase) and the friction of the movement of the interphases (the martensite growing-shrinking process). It is based on the existence of thermoelasticity/pseudo-elasticity. For local changes of composition and/or atomic order, the local temperature of transformation of the parent phase is assumed to be slightly different. The equation of Clausius-Clapeyron regulates the relationship between the external fields (temperature and stress). The results of the model with respect to changes in temperature and external stress, are consistent with the experimental measurements.

Europa and the Nereids: Wedding or Funeral?

Depictions of the abduction of Europa by the bull appear on a small group of Attic red-figure fish plates found in the Black Sea area. These plates are unusual in that they appear to be the only fish plates to bear a mythological theme, they were nearly all found in funerary contexts within a small region, and unlike most depictions of Europa and the bull, the scenes on the fish plates include Nereids among the sea creatures that accompany Europa on her journey to Crete.The presence of Nereids in these depictions helps explain the meaning of the Europa myth, and its use in these funeral sites. This article explores the meaning of Nereids as they appear in this myth and on these particular plates by analogy with their meaning elsewhere.Additionally, the many similarities between Greek perceptions of death and marriage are examined in an effort to explain the use of the Europa myth in a funerary context. It is proposed that the Nereids appear in these depictions as protectresses of Europa on her journeys: her literal sea voyage and her journey from maiden to woman, a journey that was conceived of as a metaphorical passage from life to death to rebirth.