bluuebunny/crossref_metadata_2025_split huggingface dataset:
On The Projective Invariant Representation of Conies in Computer Graphics
Authors: Herman Ivan 
Published: October 2007

AbstractA general formulation for conies and conic arcs for the purpose of computer graphics is given, based on principles and theorems of projective geometry. This approach allows the approximation of these curves by line segments to be postponed in the graphics output pipeline; it results in a more compact storage, faster approximation algorithms and smoother outlook of the curves.
Faster Phong Shading via Angular Interpolation
Authors: Kuijk AAM. , Blake E.H. 
Published: October 2007

AbstractOne of the most successful algorithms that brought realism to the world of 3D image generation is Phong shading. It is an algorithm for smooth shading meshes of planar polygons used to represent curved surfaces. The level of realism and depth perception that can be obtained by Phong shading is attractive for 3D CAD applications and related areas. However, per pixel computation costs which were too high and/or artifacts, introduced by some of the more efficient evaluation methods and apparent only when displaying moving objects, are major factors mat blocked the common usage of Phong shading in highly interactive applications.In this paper we present angular interpolation for Phong shading planar polygons. Angular interpolation was a method especially designed to meet requirements as imposed by special purpose hardware we developed1, but turned out to be generally applicable. The angular interpolation method appears to be very efficient and reduces artifacts when displaying moving objects. Ideally a shading algorithm imposes no need for subdivision of patches as presented by the solid modelling system. Shading calculation via angular interpolation yields such an ideal algorithm. We will describe two alternative evaluation methods that trade off evaluation cost against level of accuracy. They both can handle light source and view point at arbitrary distances, but differ in level of accuracy. As a consequence these alternative evaluation methods do impose restrictions on the topology of patches and light sources. However, generally, the limitations imposed by these alternative shading methods are much more liberal than the limitations on patch size imposed by the geometry.The most economic evaluation method we present can incrementally compute the colour intensity along a scanline by two additions per pixel. The methods presented are generally applicable and can easily be implemented in hardware.
Anti‐aliased Ray Tracing with Covers
Authors: Thomas D. , Netravali Arun N. , Fox D.S. 
Published: October 2007

AbstractA fast and effective object space method for antialiasing ray‐traced pictures is introduced. Traditionally, anti‐aliasing has been done using super‐sampling. However, this is costly since it requires casting large numbers of rays to obtain sample densities above the displayed pixel density. It is also wasteful since much of the information in these samples is discarded when they are filtered to yield the anti‐aliased pixels. We avoid these problems by performing the filtering in the object space using the geometry of ray‐surface intersections rather than by casting extra rays. In addition, we only perform filtering at a pixel if edges are nearby. We detect these edges by observing the order in which the pixel's rays pass through cover surfaces constructed just inside and outside the surface of each object. Shadows, reflections and refractions can be anti‐aliased using this method and a variety of object types can be handled including ellipsoids, polyhedra, and objects formed using set operations.Our anti‐aliasing gives a high image quality that can only be approached by using super‐sampling densities at least four times the display pixel density. Moreover, since the overhead of our method is small, it would take three to four times as long to render an anti‐aliased image using super‐sampling than it would with our method. Furthermore, covers allow sampling densities less than the displayed pixel density. When this is done, anti‐aliased images can be rendered twice as fast as with no anti‐aliasing and six to eight times as fast as when super‐sampling is used for anti‐aliasing.
Top Draw: A Structure Network Visualiser for PHIGS
Authors: Howard T.W. 
Published: October 2007

AbstractThe Programmer's Hierarchical Interactive Graphics System (PHIGS) is an International Standard for computer graphics. PHIGS provides a flexible mechanism for creating hierarchical models from collections of directed acyclic graphs known as ‘structure networks’. In practice, the combination of powerful data structuring facilities and the ability to dynamically edit structure networks can lead to a potential complexity which makes models difficult to manage and maintain reliably.This paper presents TopDraw, a portable programming tool for visualising PHIGS structure networks, by automatically documenting their topology using diagrams. Drawing tidy representations of graphs algorithmically is a difficult problem, and most existing systems are large, complex and speciallsed The alternative approach taken in TopDraw is to use a fast, straightforward algorithm supplemented when necessary by an interactive 'tidief. A novel feature of TopDraw is that the diagrams it produces are themselves PHIGS structures, which the application may edit and manipdate as required. TopDraw is a component of the PHIGS Toolkit, an emerging set of portable integrated tools for PHIGS environments.
Combining Graphics and Windowing Standards in the XGKS System
Authors: Rogers Greg , Sung Kelvin , Kubitz William 
Published: October 2007

AbstractIn the past few years we have seen the acceptance of standards for both two and three dimensional computer graphics. Also during this time, the workstation community has converged on a common windowing system. This paper discusses the problems encountered in implementing graphics standards such as GKS and PHIGS PLUS within the X Window System environment.
GosiP: A GKS3D Shell for PHIGS
Authors: French Michael 
Published: October 2007

AbstractGosip is an implementation of a GKS‐3D level 2c interface to PHIGS. It allows GKS applications to run on PHIGS platforms, offering performance and portability across a wide range of high‐performance 3D workstations. Compatibility of the standards is reviewed. A selection of design solutions is given for the problems of error processing, non‐retained primitives and attribute management. The concepts of Workstation Display Session and atmbute state are introduced. Some comments are made on implementation dependencies, performance and portability.
Dürer, Gaskets and Barnsley's Chaos Game
Authors: Jones Huw 
Published: October 2007

AbstractMichael Barnsley has generated the Sierpinski triangle or gasket using his “Chaos Game”, a technique for generating random points within a fractal object. Extensions of the method are discussed to generate fractal “gaskets” based on other regular polygons. One such figure resembles a tiling pattern based on pentagons known to Albrecht Dürer almost 500 years ago.
RECENT ECONOMIC TRENDS
Authors: LESER C. E. V. 
Published: October 2007

Summary

The gross reproduction rates for Scottish cities and counties have come much closer to each other between 1930‐32 and 1950‐52. This process has taken the form of spectacular increases in some counties with small populations and decreases by smaller amounts in cities and counties with large populations.
To a considerable extent this has been due to reductions in the differences in the proportions of married women in the reproductive age‐groups. This may be due not only to greater uniformity in marriage habits but also to less migration of single women to a few areas traditionally employing women.
Local variations in legitimate and illegitimate fertility have also diminished, but the pattern of regional differentials has persisted more than in the field of nuptiality.
UK EXCESS SHARE RETURNS: FIRM SIZE AND VOLATILITY
Authors: Fraser Patricia 
Published: October 2007

AbstractUsing the family of GARCH‐M(p, q) models and UK data comprising of the market portfolio and a portfolio of smaller company shares over the period January 1970 through June 1994, this paper provides support for the notion that the degree of market capitalisation is an important factor in the analysis of risk‐return relationships. The evidence reported supports the view that, although both portfolios appear to be driven by the persistence of volatility shocks, there exist significant differences in risk‐return behaviour.
SUNK COSTS AND PROFIT TAXATION: A SOURCE OF TAX NON‐NEUTRALITY
Authors: Panteghim Paolo M. 
Published: October 2007

AbstractThis Paper uses a two‐period Von Stackelberg model to study the effects of profit taxation on the behaviour of a monopolist, when the entry of a potential competitor is threatened. A barrier to entry, consisting of a sunk cost, is assumed. If the potential competitor decides to enter, thus making a loss, deduction is allowed in the following period. This model shows that these tax deductions can make profit taxation be distortive.
A CONTINGENT VALUATION STUDY OF UNCERTAIN ENVIRONMENTAL GAINS
Authors: Macmillan Douglas , Hanley Nick , Buckland Steve 
Published: October 2007

AbstractAcid deposition in a present and future cause of biodiversity losses in vulnerable upland areas of Scotland important for nature conservation. However, the exact nature of damages under the status quo, and both the timing and extent of recovery of upland ecosystems if deposition is reduced, are subject to uncertainty. this uncertainty complicates damages cost estimation. In this paper, we have explored the use of CVM to measure the willingness to pay (WTP) of the Scottish population for uncertain recovery/damage scenarios from reduced acid rain deposition. An optimally‐designed referendum format was used utilising the distribution of open‐ended bids from a pilot study to determine bid amounts and sampling size for each bid amount. Eight explanatory variables, including future damage level were selected in a non‐linear step‐wise regression analysis. Average household WTP for abatement of acid rain was £247 and £351 per year when faced with low and high future damage levels respectively. Recovery level and recovery time did not significantly influence WTP. When faced with risky outcomes regarding future damage and recovery level, respondent were found to be risk averse to both environmental gains and losses.
NIDA522131, a new radioligand for imaging extrathalamic nicotinic acetylcholine receptors: in vitro and in vivo evaluation
Authors: Chefer Svetlana I. , Pavlova Olga A. , Zhang Yi , Vaupel D. Bruce , Kimes Alane S. , Horti Andrew G. , Stein Elliot , Mukhin Alexey G. 
Published: September 2007

AbstractA novel radioligand, 6‐chloro‐3‐((2‐(S)‐azetidinyl)methoxy)‐5‐(2‐fluoropyridin‐4‐yl)pyridine (NIDA522131), for imaging extrathalamic nicotinic acetylcholine receptors (nAChRs) was characterized in vitro and in vivo using positron emission tomography. The Kd and T1/2 of dissociation of NIDA522131 binding measured at 37°C in vitro were 4.9 ± 0.4 pmol/L and 81 ± 5 min, respectively. The patterns of radioactivity distribution in monkey brain in vivo was similar to that of 2‐[18F]fluoro‐3‐(2(S)‐azetidinylmethoxy)pyridine (2FA), a radioligand that has been successfully used in humans, and matched the α4β2* nAChRs distribution. Comparison between [18F]NIDA522131 and 2FA demonstrated better in vivo binding properties of the new radioligand and substantially greater radioactivity accumulation in brain. Consistent with [18F]NIDA522131 elevated affinity for nAChRs and its increased lipophilicity, both, the total and non‐displaceable distribution volumes were substantially higher than those of 2FA. Estimated binding potential values in different brain regions, characterizing the specificity of receptor binding, were 3–4 fold higher for [18F]NIDA522131 than those of 2FA. Pharmacological evaluation in mice demonstrated a toxicity that was comparable to 2FA and is in agreement with a 2300 fold higher affinity at α4β2* versus α3β4* nAChRs. These results suggest that [18F]NIDA522131 is a promising positron emission tomography radioligand for studying extrathalamic nAChR in humans.
FROM LEEDS TO LEADS
Authors: Thomas P. R. 
Published: October 2007

Abstract The paper outlines the author's background and continuing education in photogrammetry. The potential of low cost instruments for non‐specialists is examined from her viewpoint as a research student and as an employee of Leica UK Ltd. Résumé Ľarticle retrace les compétences acquises par ľauteur en photogrammétrie et lew prolongement en formation continue. Ľauteur présente également les possibilityé des appareils à bas prix pour les non‐spécialistes en so plaçant à un double point de vue, en tant qu'tudiant faisant de la recherche et en tant qu'employee de la Société Leica Ltd. (RU). Zusammenfassung In dem Artikel werden die Ausbildung und die fortwährende Weiter‐bildung der Autorin in Photogrammetrie skizziert. Der Nutzen preiswerter Gerdte für Nichtspezialisten wird unter ihrem Blickwinkel als Forschungs‐student und Mitarbeiterin der Leica UK Ltd. beleuchtet.
XVIIth INTERNATIONAL CONGRESS OF PHOTOGRAMMETRY AND REMOTE SENSING
Authors: Atkinson K. B. , Dowman I. J. , Farrow J. E. , Newby P. R. T. , Newton I. , Smith M. J. , Stirling D. M. 
Published: October 2007

Abstract The XVIIth International Congress of Photogrammetry and Remote Sensing was held in the Washington Convention Center, Washington, DC, USA from 2nd to 14th August, 1992. Reports on the Technical Commission activities, on the Congress Exhibition and on the General Assembly were given at a meeting of the Photogrammetric Society on 20th October 1992. Papers from the Congress were published in the International Archives of Photogrammetry and Remote Sensing 29.Resume Le XVIPème Congrès de la Société Internationale de Photogrammétrie et de Télédétection s'est tenu an Washington Convention Center, Washington D.C., Etats‐Unis. du 2 au 14 août 1992. La Société britannique de Photogrammétrie a organisé une réunion le 20 octobre 1992 au cours de laquelle des rapports sur les activités des Commissions Techniques, et sur ľexposition et ľAssemblée Générate du Congrès ont été présentés. Les communications déposées au Congrès ont été publicées dans les Archives internationales de Photogrammétrie et de Télédetéction, n° 29.Zusammenfassung Der XVII. Internationale Kongreβ für Photogrammetrie und Fernerkundung wurde vom 2. bis 14. August 1992 in den USA im Washington Convention Center in Washington, D.C. durchgeführt. Berichte über die Tätigkeit der Technischen Kommissionen, die Kongreβ‐Ausstellung und di Generalversammlung wurden am 20. Oktober 1992 auf einer Versammlung der Photogrammetric Society gegeben. Beiträge vom Kongreβ wurden im Internationalen Archiv für Photogrammetrie und Fernerkundung, Bd. 29 veröffentlicht.
RELATIVE ORIENTATION FOR TWO‐MEDIA PHOTOGRAMMETRY
Authors: Shan Jie 
Published: October 2007

Abstract This paper discusses analytical relative orientation for two‐media photogrammetry. After a brief introduction concerning the collinearity condition, the coplanarity equation is derived, which is similar inform to the conventional expression. By considering the differences from one‐medium photogrammetry, the computational strategy of relative orientation for two‐media photogrammetry is studied, including linearization of the equation, the correction for refraction and, especially, the determination of the boundary between the two media. Simulated test results verify the theoretical analysis. Résumé On étudie dans cet article ľ orientation relative analytique dans la photogrammétrie à deux milieux. Après une brève introduction relative à la condition de colinéarité, on en dérive les équations de coplanarité dont la forme est tout à fait semblable à celle du cas classique. On dégage ensuite une stratégie de calcul de ľ orientation relative pour la photogrammétrie à deux milieux, en s'attachant aux différences avec celle à un seul milieu, et en mentionnant la linéarisation des équations, la correction de la réfraction et, plus particulièrement, la détermination de la limite entre les deux milieux. Les résultats obtenus sur des simulations sont conformes àľ‘analyse théorique. Zusammenfassung ImArtikelwirddie analytische relative Orientierung für die Zweimedien‐Photogrammetrie diskutiert. Nach einer kurzen Einführung, die sich mit der Kollinearitätsbedingung befaβt, weden Komplanaritätsgleichungen ähnlich der konventionellen Form abgeleitet. Unter Beachtung der Unterschiede zur Einmedium‐Photogrammetrie wird die rechnerische Strategic der relativen Orientierung für die Zweimedien‐Photogrammetrie studiert. Das schließt die Linearisierung der Gleichungen, die Refraktionskorrektur und besonders die Bestimmung der Grenze zwischen den beiden Medien ein. Simulierte Testergebnisse bestdtigen die theoretische Analyse.
DP+1: Another Simple Endpoint for Atrial Flutter Ablation
Authors: ZAMBITO PETER E. , PALMA EUGEN C. 
Published: October 2007

Background: When double potentials (DP) on the line of block are difficult to see, we propose another simple method to verify complete bidirectional block (CBDB) at the end of an atrial flutter ablation. We measured the interval between the electrograms immediately on either side of the line of block on a multipole catheter spanning the isthmus. We called this interval “DP+1” because it is one pair of electrodes away from the DP on the line of block. Methods: Fifty consecutive patients (age 62 ± 13 years, LVEF 54 ± 11%, mean cycle length 241 ± 34 ms) underwent an atrial flutter ablation using a duodecapolar catheter with 2–10 mm spacing with the distal tip inserted into the mid‐coronary sinus and the rest of the poles spanning the isthmus and the low lateral right atrium. Radiofrequency ablation was performed using a 10‐mm tip electrode (EP Technologies). The ablation endpoint was the creation of a craniocaudal activation pattern of the opposite wall to the pacing site (septal and lateral of the line of block). Results: The ablation endpoint was achieved in 48 of 50 (96%) patients with 8 ± 2 RF applications. Adequate DP were found in only 22 of 50 patients (44%), but the DP+1 interval was measurable in all patients. When no block was present, the DP+1 interval was 81 ± 10 ms, and 160 ± 18 ms when complete bidirectional block was present (P < 0.001). A DP+1 interval of >140 ms had 100% specificity, 96% sensitivity, 100% positive predictive value for verifying complete bidirectional block. After a follow‐up of 528 ± 253 days, there were no recurrences of AFL, but there were four recurrences of AF (8%). Conclusion: When DP cannot be seen, another simple method for verifying CBDB in ablation of typical atrial flutter is a DP+1 interval > 140 ms.
Early Recurrence of Ventricular Fibrillation After Successful Defibrillation During Prolonged Global Ischemia in Isolated Rabbit Hearts
Authors: WU TSU‐JUEY , LIN SHIEN‐FONG , HSIEH YU‐CHENG , CHEN PENG‐SHENG , TING CHIH‐TAI 
Published: October 2007

Introduction: The mechanisms that lower the efficacy of electrical defibrillation during prolonged global ischemia remain unclear. Methods and Results: Epicardial activation patterns during attempted electrical defibrillation were studied in 18 Langendorff‐perfused rabbit hearts at baseline, after 5‐minute no‐flow global ischemia and after 10‐minute reperfusion. DFT50 (voltage required to achieve 50% probability of successful defibrillation) was determined at each stage. Defibrillation was considered successful if postshock sinus/idioventricular rhythm was present. Prolonged global ischemia converted type 1 VF (multiple wandering wavelets) into type 2 VF (repetitive epicardial breakthroughs, REBs). The mean DFT50 after 5‐minute ischemia (96 ± 39 V) was significantly lower when compared with that at baseline (154 ± 47 V, P < 0.0001) and after 10‐minute reperfusion (145 ± 47 V, P < 0.001). However, the incidence of early (within 10 seconds) VF recurrence after successful shock during prolonged global ischemia (23 of 78, 29.5%) was much higher than that at baseline (2 of 60, 3.3%) and after 10‐minute reperfusion (5 of 63, 7.9%; P < 0.0001). Mapping data showed that the VF wavefronts during prolonged global ischemia were initially halted by the shock, followed by one to five ventricular escape beats. These beats then triggered REBs and early VF recurrence. In eight out of 11 episodes, the REBs before and after successful shock arose from the same location near the interventricular septum. Conclusions: There is a significant reduction of DFT50 during prolonged global ischemia. However, defibrillation appears to fail when the preexisting REBs near the interventricular septum induce early VF recurrence. Shock per se cannot eliminate the substrates of these REBs.
Plasma MMP‐2‐TIMP‐2 complex levels measured during follow‐up predict a risk of relapse in patients with malignant lymphoma
Authors: Pennanen Heli , Kuittinen Outi , Turpeenniemi‐Hujanen Taina 
Published: October 2007

AbstractObjectives:  Circulating gelatinases and their tissue inhibitors measured at diagnosis have been shown to exhibit prognostic relevance in several solid tumours. The clinical data concerning their role in follow‐up of cancer are still very preliminary. The aim of this study was to find out whether the concentrations of these circulating markers could be used as follow‐up markers predicting the risk of lymphoma relapse.Methods:  Here, we investigated these circulating molecules in a large (n = 126) follow‐up material of lymphoma patients and in healthy controls (n = 44). The plasma samples of patients with Hodgkin’s lymphoma (n = 31), non‐Hodgkin’s lymphoma (n = 95), and healthy controls were analysed by enzyme‐linked immunosorbent assay for matrix metalloproteinase‐9 (MMP‐9), proMMP‐2, matrix metalloproteinase‐2‐tissue inhibitor of metalloproteinase‐2 (MMP‐2‐TIMP‐2) complex, TIMP‐1, and TIMP‐2.Results:  The patients with the highest plasma levels of MMP‐2‐TIMP‐2 complex had a 3‐fold risk of relapse when compared to the patients with lower levels (P = 0.036). Plasma levels of proMMP‐2 and MMP‐2‐TIMP‐2 complex as well as the proMMP‐2/TIMP‐2 ratio were significantly higher in patients with active lymphoma and those in remission when compared to healthy controls. On the contrary, the values of TIMP‐2 were significantly lower in lymphoma patients than in controls.Conclusions:  This study shows that lymphoma patients with the highest levels of MMP‐2‐TIMP‐2 complex are at a marked risk of relapse. Moreover, plasma levels of MMP‐2‐TIMP‐2 complex, proMMP‐2, TIMP‐2, and proMMP‐2/TIMP‐2 ratio are at abnormal level in patients with newly diagnosed lymphoma and those in remission when compared to healthy controls. They remain abnormal even after successful lymphoma treatments.
Association between recipient ICAM‐1 K469 allele and renal allograft acute rejection
Authors: Tajik N. , Salari F. , Ghods A. J. , Hajilooi M. , Radjabzadeh M. F. , Mousavi T. 
Published: October 2007

SummaryIntercellular adhesion molecule 1 (ICAM‐1) genetic polymorphisms (G241R and K469E) have been implicated in several autoimmune and inflammatory conditions. Investigating a sample of living‐unrelated donor (LURD) kidney transplant pairs, we revealed an association between recipient K469 allele (P = 0.013) and K/K genotype (P = 0.042) with renal allograft acute rejection.
Preservation of basophils in dapsone‐induced agranulocytosis suggests a possible pathogenetic role for leucocyte peroxidases
Authors: BESSER M. , VERA J. , CLARK J. , CHITNAVIS D. , BEATTY C. , VASSILIOU G. 
Published: October 2007

SummaryWe describe a hitherto unreported laboratory observation, namely the selective preservation of basophils, in a case of severe dapsone‐induced agranulocytosis. Dapsone is known to be metabolised by peroxidases to nitroso derivatives in non‐hemopoietic cells where these can in turn act as haptens. Our observation that basophils are selectively spared in this syndrome supports the hypothesis that leucocyte peroxidases function in a similar way to facilitate the pathogenesis of this form of agranulocytosis in susceptible individuals.