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Circle
Kinds of Circle Terms modified by Circle Selected AbstractsUsing the SWAP-200 in a personality-disordered forensic population: is it valid, reliable and useful?CRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 1 2005Luisa E. Marin-Avellan Background Treatment and risk management of forensic patients relies heavily on diagnosing psychopathology, yet the reliability of clinical diagnoses of personality disorder has been found to be only fair to low. Structured instruments for the global assessment of personality disorder are infrequently used in clinical assessments possibly due to their limited validity and clinical utility. Aims/methods The Shedler-Westen Assessment Procedure-200 (SWAP-200) was developed in an effort to address these limitations. Although good reliability and validity in relation to clinicians' diagnosis of personality disorder has been reported, to date the validity of this instrument has not been assessed in relation to other standardized instruments or in a personality-disordered, forensic population. This study aims to establish the reliability and validity of the SWAP-200 against other diagnostic instruments and measures of interpersonal functioning in a personality disordered forensic population. Results This paper reports the results of 30 subjects from a high secure hospital in the UK who were assessed with the SWAP-200, the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II), the Adult Attachment Interview (AAI) and the Chart of Interpersonal Reactions in Closed Living Environments (CIRCLE). Preliminary results suggest that the SWAP-200 is a reliable instrument for the diagnosis of personality disorder in forensic patients. Conclusions Although the small sample size allows only preliminary conclusions about the validity of this instrument, early results show a reduction of the diagnosis of comorbidity compared with the SCID-II, together with an increased number of expected associations between independent measures of interpersonal functioning and categories of personality disorder. Copyright © 2005 Whurr Publishers Ltd. [source] REGARDING THE SPECTATORS OF THE BAYEUX TAPESTRY: BISHOP ODO AND HIS CIRCLEART HISTORY, Issue 2 2009T. A. HESLOP The entourage of Bishop Odo of Bayeux contained successful entrepreneurs and talented scholars. There was much to interest both groups in the Bayeux Tapestry which he commissioned. The Norman invasion of England is shown as a major logistical exercise for which the principal model was Caesar's invasion of 54 bce. Like the Romans, the Normans became successful colonists and farmed the land. The Tapestry also has epic qualities, recalling the poetic ,histories' of antiquity, especially Virgil's Aeneid, which provides parallels for episodes and incidents in the Tapestry also found in the written accounts of the Norman invasion. The rhetorical nature of history itself, ideally vivid, allusive and yet truthful, was receiving critical scrutiny at the time as part of a self-conscious revival of classical narrative styles [source] Are perceptions of parenting and interpersonal functioning related in those with personality disorder?CLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 3 2001Evidence from patients detained in a high secure setting We explored the widely-held assumption that dysfunctional interpersonal behaviour, a key characteristic of personality disorder, is associated with adverse experiences in childhood in a sample of patients detained in high secure care. We obtained Parental Bonding Inventory (PBI) and Chart of Interpersonal Relations in Closed Living Environment (CIRCLE) data from 79 patients detained at a high secure hospital. This comprised 48 with the legal classification (1983 Mental Health Act) of Psychopathic Disorder (PD) and 31 with the legal classification of Mental Illness (MI). On the PBI, the PD group had significantly lower care scores and increased protection scores compared with the MI group; the latter reported care and protection scores similar to those from published norms. The CIRCLE scores also demonstrated significantly different interpersonal functioning between the PD and MI groups, with each group typically plotted in opposing halves of the interpersonal circle (IPC). Although the PDs showed abnormalities in both the PBI and CIRCLE in the expected direction, there were no clear associations between aspects of abnormal parenting and adult dysfunctional interpersonal behaviour within this group. This finding did not confirm our hypothesis and we discuss possible explanations. Copyright © 2001 John Wiley & Sons, Ltd. [source] Broken Circle: The Isolation of Franklin D. Roosevelt in World War II*DIPLOMATIC HISTORY, Issue 5 2008Frank Costigliola First page of article [source] Closing the Circle: Travelling with ,The Railway Man'ENGLISH IN EDUCATION, Issue 2 2003Kevin Murphy No abstract is available for this article. [source] Matrix metalloproteinases 2 and 9 in human atherosclerotic and non-atherosclerotic cerebral aneurysmsEUROPEAN JOURNAL OF NEUROLOGY, Issue 10 2006J. Caird Matrix metalloproteinases 2 and 9 (MMP 2 and -9) have been implicated in the pathogenesis of atherosclerosis and aneurysm formation. The goal of the study was to establish the role of these metalloproteinases in both human atherosclerotic and non-atherosclerotic cerebral aneurysms. Eleven cerebral aneurysms (four atherosclerotic, seven non-atherosclerotic) were immunohistochemically stained for MMP 2 and -9. As controls, atherosclerotic and normal Circle of Willis arteries were similarly immunostained. All specimens were retrieved at autopsy and were paraffin-embedded. In order to evaluate the real MMP 2 and -9 activities, gelatin zymography was also performed in only two available specimens of non-atherosclerotic intracranial aneurysms, because of the relative unavailability of fresh intracranial aneurysm tissue (i.e. reluctance to excise the aneurysm fundus at surgery). Our data establish that MMP 2 and -9 were expressed minimally or not at all in normal Circle of Willis arteries but were strongly expressed in medial smooth muscle cells of atherosclerotic Circle of Willis arteries. In the aneurysm group, both MMP 2 and -9 were strongly expressed in the atherosclerotic aneurysms, but MMP 2 alone was detected in the non-atherosclerotic aneurysms. Zymography revealed a weak enzyme activity correlating to MMP 9 standard recombinant protein. MMP 2 activity was not demonstrated in either specimen. This study shows that the expression of MMP 2 and -9 is associated with atherosclerosis, be it in aneurysmal or non-aneurysmal cerebral vessels but MMP 2 appears to be specifically expressed in aneurysms devoid of atherosclerosis perhaps suggesting a pathogenic role for MMP 2 in the alteration of the extracellular matrix of cerebral arteries during aneurysm formation. [source] Quantitative Human Geography: Are We Turning Full Circle?GEOGRAPHICAL ANALYSIS, Issue 3 2008Ron Johnston First page of article [source] On the Nationalist Reconstruction of Hölderlin in the George CircleGERMAN LIFE AND LETTERS, Issue 4 2002Joseph Suglia The George Circle was primarily concerned with Hölderlin's representative character. The critics who served as the official voices of the Circle (Norbert von Hellingrath, Friedrich Gundolf, Friedrich Wolters) saw Hölderlin exclusively in national,sacrificial terms: according to their interpretations, he anticipated a Germany in which nature would be purified and in which the impact of too much ,Westernisation' would be overcome. They claimed that the poet offered a founding figure with which the German people could identify and that the sacrifices evidenced in his work reflected upon a national sacrifice that was central to the founding of the state. In their accounts, Hölderlin was conflated with his poetic figures , in particular, with Hyperion and Empedokles , and viewed entirely from the perspective of the nation that he allegedly forecast in his poetry. [source] Molecular investigations into a globally important carbon pool: permafrost-protected carbon in Alaskan soilsGLOBAL CHANGE BIOLOGY, Issue 9 2010M. P. WALDROP Abstract The fate of carbon (C) contained within permafrost in boreal forest environments is an important consideration for the current and future carbon cycle as soils warm in northern latitudes. Currently, little is known about the microbiology or chemistry of permafrost soils that may affect its decomposition once soils thaw. We tested the hypothesis that low microbial abundances and activities in permafrost soils limit decomposition rates compared with active layer soils. We examined active layer and permafrost soils near Fairbanks, AK, the Yukon River, and the Arctic Circle. Soils were incubated in the lab under aerobic and anaerobic conditions. Gas fluxes at ,5 and 5 °C were measured to calculate temperature response quotients (Q10). The Q10 was lower in permafrost soils (average 2.7) compared with active layer soils (average 7.5). Soil nutrients, leachable dissolved organic C (DOC) quality and quantity, and nuclear magnetic resonance spectroscopy of the soils revealed that the organic matter within permafrost soils is as labile, or even more so, than surface soils. Microbial abundances (fungi, bacteria, and subgroups: methanogens and Basidiomycetes) and exoenzyme activities involved in decomposition were lower in permafrost soils compared with active layer soils, which, together with the chemical data, supports the reduced Q10 values. CH4 fluxes were correlated with methanogen abundance and the highest CH4 production came from active layer soils. These results suggest that permafrost soils have high inherent decomposability, but low microbial abundances and activities reduce the temperature sensitivity of C fluxes. Despite these inherent limitations, however, respiration per unit soil C was higher in permafrost soils compared with active layer soils, suggesting that decomposition and heterotrophic respiration may contribute to a positive feedback to warming of this eco region. [source] Catheter Ablation for Atrial Fibrillation: Have We Come the Full Circle?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2008HARIS M. HAQQANI M.B.B.S. No abstract is available for this article. [source] Painless Shock Therapy: More Than Just an Attempt to Square the Circle?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2007GIUSEPPE BORIANI No abstract is available for this article. [source] Honoring children, mending the circle: cultural adaptation of trauma-focused cognitive-behavioral therapy for American Indian and Alaska Native childrenJOURNAL OF CLINICAL PSYCHOLOGY, Issue 8 2010Dolores Subia BigFoot Abstract American Indians and Alaska Natives are vulnerable populations with significant levels of trauma exposure. The Indian Country Child Trauma Center developed an American Indian and Alaska Native (AI/AN) adaptation of the evidence-based child trauma treatment, trauma-focused cognitive-behavioral therapy. Honoring Children, Mending the Circle (HC-MC) guides the therapeutic process through a blending of AI/AN traditional teachings with cognitive-behavioral methods. The authors introduced the HC-MC treatment and illustrated its therapeutic tools by way of a case illustration. © 2010 Wiley Periodicals, Inc. J Clin Psychol: In Session 66:1,10, 2010. [source] Variations in the Understanding of Interpersonal Behavior: Adherence to the Interpersonal Circle as a Moderator of the Rigidity,Psychological Well-Being RelationJOURNAL OF PERSONALITY, Issue 2 2010Terence J. G. Tracey ABSTRACT The idiothetic structure of interpersonal trait perceptions was examined as it moderated the interpersonal rigidity,psychological well-being relation. The focus was on the extent to which individuals' perceptions of the similarity of interpersonal behavior fits (i.e., adhered to) the normative interpersonal circle. In two samples of college students, individual differences in adherence to the interpersonal circle moderated the relation of interpersonal rigidity with various indices of psychological well-being. We found that those individuals whose perceptions of interpersonal traits were better represented by the interpersonal circle had negative relations between interpersonal rigidity and satisfaction with life, self-confidence, self-liking, and complementarity and positive relations with interpersonal problems. The results suggest that adherence to the interpersonal circle may be a new means of viewing traitedness and that cognitive interpretation of traits may have an important moderating function. [source] The Islamic Republic and the"Green Movement": Coming Full CircleMIDDLE EAST POLICY, Issue 4 2009Mahmood Monshipouri [source] Orbit characteristics of the tristatic EISCAT UHF meteorsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008C. Szasz ABSTRACT The tristatic EISCAT 930-MHz UHF system is used to determine the absolute geocentric velocities of meteors detected with all three receivers simultaneously at 96 km, the height of the common radar volume. The data used in this study were taken between 2002 and 2005, during four 24-h runs at summer/winter solstice and vernal/autumnal equinox to observe the largest seasonal difference. The observed velocities of 410 tristatic meteors are integrated back through the Earth atmosphere to find their atmospheric entry velocities using an ablation model. Orbit calculations are performed by taking zenith attraction, Earth rotation as well as obliquity of the ecliptic into account. The results are presented in the form of different orbital characteristics. None of the observed meteors appears to be of extrasolar or asteroidal origin; comets, particularly short-period (<200 yr) ones, may be the dominant source for the particles observed. About 40 per cent of the radiants can be associated with the north apex sporadic meteor source and 58 per cent of the orbits are retrograde. There is evidence of resonance gaps at semimajor axis values corresponding to commensurabilities with Jupiter, which may be the first convincing evidence of Jupiter's gravitational influence on the population of small sporadic meteoroids surveyed by radar. The geocentric velocity distribution is bimodal with a prograde population centred around 38 km s,1 and a retrograde population peaking at 59 km s,1. The EISCAT radar system is located close to the Arctic Circle, which means that the North Ecliptic Pole (NEP) is near zenith once every 24 h, i.e. during each observational period. In this particular geometry, the local horizon coincides with the ecliptic plane. The meteoroid influx should therefore be directly comparable throughout the year. [source] In the Circle of the Dance: Notes of an Outsider in Nepal/ An Anthropologist in Japan: Glimpses of Life in the FieldAMERICAN ETHNOLOGIST, Issue 3 2000Janet K. Fair In the Circle of the Dance: Notes of an Outsider in Nepal. Katharine Bjork Guneratne. Ithaca, NY: Cornell University Press, 1999. viii. 225 pp., map, photographs, glossary. An Anthropologist in Japan: Glimpses of Life in the Field. Joy Hendry. London: Routledge, 1999. vii +167 pp., photographs, index. [source] Proinflammatory phenotype with imbalance of KLF2 and RelA: Risk of childhood stroke with sickle cell anemia,AMERICAN JOURNAL OF HEMATOLOGY, Issue 1 2010Judy Enenstein Altered inflammation signaling within the cerebral vasculature may be an important risk factor for stroke in children with sickle cell anemia (SCA). This study examines how differential expression of NF,B/p65 (RelA), KLF2, and other transcription factors may act as switches in inflammation signaling leading to observed differences between non-SCA (NS) African Americans and African Americans with SCA who are either at risk (AR) or not at risk (NAR) of childhood stroke based on occurrence of Circle of Willis disease. Clover/Transfac analysis was used to identify overrepresented transcription factor binding motifs on genes associated with inflammation. Transcription factor binding motifs for the NF,B family and RFX1 were overrepresented on inflammation signaling gene set analysis. Variations in protein expression were determined by flow cytometry of blood outgrowth endothelial cells (BOECs) from NS, AR, and NAR donors and Western blots of protein extracts from both unstimulated and TNF,/IL1,-stimulated BOECs. BOECs from patients with SCA had more cytoplasmic-derived RelA compared with NS BOECs. Sickle BOECs also had heightened responses to inflammatory stimuli compared with NS BOECs, as shown by increased nuclear RelA, and intracellular adhesion molecule (ICAM) response to TNF,/IL1, stimulation. Multiple control points in RelA signaling were associated with risk of childhood stroke. The ratio of proinflammatory factor RelA to anti-inflammatory factor KLF2 was greater in BOECs from AR donors than NS donors. Group risk of childhood stroke with SCA was greatest among individuals who exhibited increased expression of proinflammatory transcription factors and decreased expression of transcription factors that suppress inflammation. Am. J. Hematol. 2010. © 2009 Wiley-Liss, Inc. [source] Didymus the Blind and His Circle in Late-Antique Alexandria: Virtue and Narrative in Biblical Scholarship By Richard A. LaytonTHE HEYTHROP JOURNAL, Issue 4 2006Augustine Casiday No abstract is available for this article. [source] Clio's Circle: Entering the Imaginal World of Historians by Meyer, RuthTHE JOURNAL OF ANALYTICAL PSYCHOLOGY, Issue 5 2008Kevin Lu No abstract is available for this article. [source] Topography of Arterial Circle of the Brain in Egyptian Spiny Mouse (Acomys cahirinus, Desmarest)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2007A. Szczurkowski Summary Using stained acryl latex-injected techniques, the arterial circle of the brain in Acomys cahirinus Desmarest was studied. Results revealed an important individual variability of investigated structure. Three morphological variants were found: (1) the lack of typical arterial circle , opened in front and the back side, (2) partial opened at the back side, (3) completely closed arterial circle. This finding is opposed to many species of mammals, including rodents, and especially laboratory mouse. In our point of view, it seems to be a specific character. [source] Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009Susanna Piovano Abstract 1.A known fishing hot spot for loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea is in the waters of the Strait of Sicily where interactions with fish hooks and branchlines are believed to be a major cause of mortality for sea turtles. 2.Hooks with different shapes but a similar gape width (circle hook size 16/0 vs J hook size 2) were tested in order to determine the potential effectiveness of the hook design to both reduce sea turtle capture as well as to maintain acceptable levels of target species capture rates in a shallow-set longline swordfish fishery in the Mediterranean. 3.Seven experimental fishing trips, 30,000 hooks total, were conducted on a single commercial fishing vessel (18,m in length) in the Strait of Sicily during the months of July through October over a period of three years from 2005 to 2007. Circle and J hooks were alternated along the mainline. 4.A total of 26 sea turtles were hooked, all immature-size Caretta caretta. Turtles were caught at a statistically greater frequency on J hooks than on circle hooks. The capture rate, weight, and upper jaw fork length of the target species were not significantly different between the two types of hooks employed. 5.Five sea turtles swallowed the hook and in all such cases these were J type. Circle hooks tended to be located externally and were more easily detected by fishermen, and could be removed with the correct dehooking action before returning the turtle to the sea. 6.These findings suggest that 16/0 circle hooks can effectively reduce the incidental capture of immature loggerhead sea turtles in a Mediterranean swordfish longline fishery without affecting the catch size of the target species. Copyright © 2009 John Wiley & Sons, Ltd. [source] The Troughton & Simms transit circle of Coimbra Astronomical Observatory from the 1850s: An example of the dissemination of technological developmentsASTRONOMISCHE NACHRICHTEN, Issue 6 2009V. Bonifácio Abstract Yesterday, as today, technological developments led by large and expensive instrumental projects are later on disseminated to smaller and more affordable devices. In 1847, Airy requested a new transit circle for the Greenwich Observatory. When the first observation was performed, on 4 January 1851, Airy's Greenwich Transit Circle (ATC) was the largest instrument of its class in the world. The construction of the ATC implied solving several technical difficulties, for example, the maintenance of the instrument rigidity and the illumination of the graduated circle and telescope field of view. After the ATC completion Troughton & Simms stand at the 1851 Great London Exhibition included two small transit instruments which were praised for their telescope field of view/eyepiece wires illumination. One of which, was based upon the design implemented beforehand on the ATC. In this paper we will discuss the field and eyepiece wire illumination innovations introduced on the ATC and the Simms transit instruments exhibited in 1851. We will also describe the small Troughton & Simms transit circle currently belonging to Coimbra Astronomical Observatory collection that is, we believe, one of the earliest implementation of this ATC lead development (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Speciation mirrors geomorphology and palaeoclimatic history in African laminate-toothed rats (Muridae: Otomyini) of the Otomys denti and Otomys lacustris species-complexes in the ,Montane Circle' of East AfricaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009PETER J. TAYLOR We adopted an integrated systematic approach to delimit evolutionary species and describe phylogeographic, morphometric and ecological relationships in Otomys denti (from the Albertine Rift, Southern Rift in Malawi and the northern Eastern Arc Mountains) and Otomys lacustris (from the Southern Rift in Tanzania and Zambia, and the southern Eastern Arc Mountains). Molecular [cytochrome (cyt) b sequences, 1143 bp, N = 18], craniometric (classical, N = 100 and geometric, N = 60) and ecological (Partial Least Squares regression of shape and ecogeographic variables) approaches show a profound, parallel disjunction between two groups: (1) Eastern Arc and Southern Rift (including the Malawi Rift) (O. lacustris and Otomys denti sungae) and (2) Albertine Rift (Otomys denti denti and Otomys denti kempi) taxa. Within both groups, cyt b sequences or craniometric analysis provided evidence for the differentiation of both southern and northern Eastern Arc from Southern Rift lineages (across the so-called Makambako Gap). Within the Albertine Rift (denti,kempi) lineage, populations from individual mountain ranges differed significantly in skull shape (but not size), but were similar genetically. Over-reliance in the past on very few morphological characters (e.g. number of molar laminae) and a polytypic species concept has obscured phylogenetic relationships and species discrimination in this group. We recognize at least three species in this group, and distinct lineages within two of these species. Each species or lineage was endemic to one of three regions: the Albertine Rift, the Malawi Rift or the Eastern Arc. Our result echo conclusions of recent studies of other mammalian and bird taxa and reflect the geomorphology and palaeoclimatic history of the region. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 913,941. [source] Using Quality Circles to Enhance Student Involvement and Course Quality in a Large Undergraduate Food Science and Human Nutrition CourseJOURNAL OF FOOD SCIENCE EDUCATION, Issue 1 2005S.J. Schmidt ABSTRACT: Large undergraduate classes are a challenge to manage, to engage, and to assess, yet such formidable classes can flourish when student participation is facilitated. One method of generating authentic student involvement is implementation of quality circles by means of a Student Feedback Committee (SFC), which is a volunteer problem-solving and decision-making group that communicates student-generated input to the teaching team for the purpose of improving the course content, structure, and environment in the present and redesigning it for the future. Our objective was to implement a SFC in a large introductory Food Science and Human Nutrition (FSHN 101) course to enhance student involvement and course quality. Overall, the SFC provided a continuous and dynamic feedback mechanism for the teaching team, a beneficial experience for the SFC members, and an opportunity for class members to confidentially share their input to enhance the quality of the course throughout the semester. This article includes a brief introduction of the use of quality circles in higher education classrooms, as well as our methods of implementation and assessment after using the SFC for 3 semesters (Spring 2003, Fall 2003, and Spring 2004). [source] Cobble Circles and Standing Stones: Archaeology at the Rivas Site, Costa RicaJOURNAL OF LATIN AMERICAN & CARIBBEAN ANTHROPOLOGY, Issue 2 2004Kira Blaisdell-Sloan Cobble Circles and Standing Stones: Archaeology at the Rivas Site, Costa Rica. Jeffrey Quilter, Iowa City: University of Iowa Press, 2004. 218 pp. [source] Lives in Motion: Composing Circles of Self and Community in JapanAMERICAN ETHNOLOGIST, Issue 3 2001Jan Zeserson Lives in Motion: Composing Circles of Self and Community in Japan. Susan Orpett Long. ed. Ithaca, NY: Cornell University Press, 1999. vii. 295 pp., tables, photographs, index. [source] Farbskalen,Farbkreise,Farbsysteme (Color Scales, Color Circles, Color Systems), by Werner Spillmann, reprint available from Applica, Grindelstrasse 2, 8304 Wallisellen, Switzerland, 23 pp/SFr.COLOR RESEARCH & APPLICATION, Issue 5 2003No abstract is available for this article. [source] ,Concentric Circles' at the Periphery of the European UnionAUSTRALIAN JOURNAL OF POLITICS AND HISTORY, Issue 3 2000Karis Muller After World War II when the governments of several European states attempted to form supranational groupings, colonial obligations posed problems that persist to this day. The article traces immediate postwar history, outlining the present relationship between the EC institutions and what remain of member-state Empires, before proceeding to two case studies. The first concerns the ramifications of ,Euroland' in present or past dependencies after European Monetary Union. The second considers the role of European dependencies in military alliances and analyses how one of the founding Treaties was used in the mid-1990s after the discovery that it applied extra-territorially. The conclusion is that the external border of multi-speed Europe is even more variable than it might otherwise be because of the attachments some member states retain to colonial remnants. [source] Digital simulation of the transformation of plane stressCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2009Wei-Pin Lee Abstract In this study, we developed a computer program to simulate the transformation of plane stress by using Visual Basic.NET. We applied the equations of stress transformation to plane stress problems to calculate the stresses with respect to the 1,2 axes, which are rotated counterclockwise through an angle , about the x,y origin, and showed the visual results on the screen. In addition, we used animation to observe the change of plane stress. This program was then used in teaching courses, such as Mechanics of Materials and Linear Algebra. Use of the software may help students to understand principal stresses, principal axes, Mohr's circle, eigenvalues, eigenvectors, similar matrices, and invariants. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 25,33, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20180 [source] The Perspective Silhouette of a Canal SurfaceCOMPUTER GRAPHICS FORUM, Issue 1 2003Ku-Jin Kim We present an efficient and robust algorithm for parameterizing the perspective silhouette of a canal surface and detecting each connected component of the silhouette. A canal surface is the envelope of a moving sphere with varying radius, defined by the trajectoryC(t)of its center and a radius functionr(t). This moving sphere,S(t), touches the canal surface at a characteristic circleK(t). We decompose the canal surface into a set of characteristic circles, compute the silhouette points on each characteristic circle, and then parameterize the silhouette curve. The perspective silhouette of the sphereS(t)from a given viewpoint consists of a circleQ(t); by identifying the values oftat whichK(t)andQ(t)touch, we can find all the connected components of the silhouette curve of the canal surface. ACM CSS: I.3.7 Computer Graphics,Three Dimensional Graphics and Realism [source] | |||||||||||||||||||||||||||||||||||||||||||