bluuebunny/crossref_metadata_2025 huggingface dataset:
Modifying Queries on Complex Objects in Database Federations
Authors: Vermeer Mark. W. W. , Apers Peter M. G.
Published: October 2003

We discuss the modification of queries against an integrated view in a federation of object-oriented databases. We present a generalization of existing algorithms for simple global query modification that works for arbitrarily defined integration classes. We then extend this algorithm to deal with object-oriented features that have been neglected in literature, viz. queries involving path expressions and nested queries. We show how properties of the OO-style of modeling relationships through object references can be exploited to reduce the number of subqueries necessary to evaluate such queries.
Context-Based Naming in Information Bases
Authors: Theodorakis Manos , Constantopoulos Panos
Published: October 2003

In information bases following semantic and object-oriented data models, logical names are used for the external identification of objects. Yet the naming schemes employed are not "natural" enough and several problems often arise: logical names can be ambiguous, excessively long, unrelated to or unable to follow the changes of the environment of the named object. In natural language, similar problems are resolved by the context within which words are used. An approach to introducing a notion of context in an information base is to provide structuring mechanisms for decomposing it into possibly overlapping parts. This paper focuses on developing a context mechanism for an information base and, in particular, exploiting this mechanism for naming purposes. Rules are developed for generating meaningful names for objects by taking their context into account. This context-based naming enhances name readability, resolves name ambiguities, saves a lot of redundant name substrings, and it localizes and thus facilitates consistency checking, query processing and update operations. In modeling, it supports systematic naming of objects, and thus enhances cooperation between the designers and the end-users in the sense that the contents of the information base are more understandable by both of them.
Extending Database Support for Coordination Among Agents
Authors: Berndtsson Mikael , Chakravarthy Sharma , Lings Brian
Published: October 2003

Coordination and collaboration are naturally used by groups for carrying out activities and solving problems that require cooperation. However, getting a set of computer agents to do the same has been a problem – primarily addressed by the AI community and recently by the database community as workflow and process management problems (for example, in business processes, electronic commerce, logistics). Not surprisingly, the problem has been addressed at different levels of abstraction by the two communities. Coordination protocols as well as task and result sharing have been investigated by the AI community; specification of alternative transaction models to meet the requirements of non-traditional applications, and their execution have been addressed by the database community. It is evident that there is a need for bringing the two approaches together to develop systems that support cooperative problem solving. This paper – argues for the use of active databases in general and active capability in particular as an enabling technology for cooperative problem solving and cooperative information systems – details a novel approach for supporting task sharing, a key aspect of CPS, using active capability – elaborates on a methodology for mapping task shared protocols expressed in high level speech acts to Event Condition-Action (ECA) rules.
Integrated Optoelectronics Using Thin Film Epitaxial Liftoff Materials and Devices
Authors: Jokerst N. M.
Published: October 2003

The separation of single crystal thin film epitaxial compound semiconductor layers from a lattice matched growth substrate through selective etching, with subsequent bonding of the epitaxial thin film devices onto host substrates, is an emerging tool for multi-material, hybrid integration. Progress to date in this area, presented herein, includes advanced thin film devices, thin film material separation and device integration processing techniques, and thin film material and device integration with host substrates which include silicon circuitry, polymers, glass, and lithium niobate.
A Dynamic Causal Modeling Study on Category Effects: Bottom–Up or Top–Down Mediation?
Authors: Mechelli Andrea , Price Cathy J. , Noppeney Uta , Friston Karl J.
Published: October 2003

In this study, we combined functional magnetic resonance imaging (fMRI) and dynamic causal modeling (DCM) to investigate whether object category effects in the occipital and temporal cortex are mediated by inputs from early visual cortex or parietal regions. Resolving this issue may provide anatomical constraints on theories of category specificity— which make different assumptions about the underlying neurophysiology. The data were acquired by Ishai, Ungerleider, Martin, Schouten, and Haxby (1999, 2000) and provided by the National fMRI Data Center (http://www.fmridc.org). The original authors used a conventional analysis to estimate differential effects in the occipital and temporal cortex in response to pictures of chairs, faces, and houses. We extended this approach by estimating neuronal interactions that mediate category effects using DCM. DCM uses a Bayesian framework to estimate and make inferences about the influence that one region exerts over another and how this is affected by experimental changes. DCM differs from previous approaches to brain connectivity, such as multivariate autoregressive models and structural equation modeling, as it assumes that the observed hemodynamic responses are driven by experimental changes rather than endogenous noise. DCM therefore brings the analysis of brain connectivity much closer to the analysis of regionally specific effects usually applied to functional imaging data. We used DCM to estimate the influence that V3 and the superior/inferior parietal cortex exerted over category-responsive regions and how this was affected by the presentation of houses, faces, and chairs. We found that category effects in occipital and temporal cortex were mediated by inputs from early visual cortex. In contrast, the connectivity from the superior/inferior parietal area to the category-responsive areas was unaffected by the presentation of chairs, faces, or houses. These findings indicate that category effects in the occipital and temporal cortex can be mediated by bottom–up mechanisms—a finding that needs to be embraced by models of category specificity.
Goal-Directed Hand Movements Are Not Affected by the Biased Space Representation in Spatial Neglect
Authors: Himmelbach Marc , Karnath Hans-Otto
Published: October 2003

Patients with spatial neglect exhibit a severe shift of spontaneous explorative movements to the right side, indicating a bias of long-living representations of space. Whether or not goal-directed movements likewise are affected by this rightward bias has been controversially discussed throughout the last decade. Unfortunately, substantial differences regarding patient selection and data analysis prevented a direct comparison of these results. We thus studied pointing movements in a new sample of subjects covering all different patient groups previously investigated on this issue. We analyzed all the different measures of hand path curvature used so far and, in addition, suggest a new measure that avoids the disadvantages of the previously used parameters. Despite their severe bias for exploratory movements, we did not find systematic, direction-specific deviations of goal-directed hand movements that were specific for the patients with spatial neglect. The results strongly suggest that the disturbance of long-living spatial representations underlying the bias of exploratory behavior in patients with neglect does not influence the performance of goal-directed movements. The data support the view of a dual mode of space representation in the posterior parietal and the superior temporal cortex.
Comparison of Early Cortical Networks in Efficient and Inefficient Visual Search: An Event-Related Potential Study
Authors: Leonards Ute , Palix Julie , Michel Christoph , Ibanez Vicente
Published: October 2003

Functional magnetic resonance imaging studies have indicated that efficient feature search (FS) and inefficient conjunction search (CS) activate partially distinct frontoparietal cortical networks. However, it remains a matter of debate whether the differences in these networks reflect differences in the early processing during FS and CS. In addition, the relationship between the differences in the networks and spatial shifts of attention also remains unknown. We examined these issues by applying a spatio-temporal analysis method to high-resolution visual event-related potentials (ERPs) and investigated how spatio-temporal activation patterns differ for FS and CS tasks. Within the first 450 msec after stimulus onset, scalp potential distributions (ERP maps) revealed 7 different electric field configurations for each search task. Configuration changes occurred simultaneously in the two tasks, suggesting that contributing processes were not significantly delayed in one task compared to the other. Despite this high spatial and temporal correlation, two ERP maps (120–190 and 250–300 msec) differed between the FS and CS. Lateralized distributions were observed only in the ERP map at 250–300 msec for the FS. This distribution corresponds to that previously described as the N2pc component (a negativity in the time range of the N2 complex over posterior electrodes of the hemisphere contralateral to the target hemifield), which has been associated with the focusing of attention onto potential target items in the search display. Thus, our results indicate that the cortical networks involved in feature and conjunction searching partially differ as early as 120 msec after stimulus onset and that the differences between the networks employed during the early stages of FS and CS are not necessarily caused by spatial attention shifts.
Mapping Institutional Linkages in European Air Pollution Politics
Authors: Selin Henrik , VanDeveer Stacy D.
Published: October 2003

The growing literature about linkages between international institutions remains littered with proposed taxonomies. Most of these taxonomies are conceptual, rather than empirically driven, remaining too vague to offer guidance for empirical research regarding linkages as possible avenues of influence across international institutions. This article argues that institutional linkages are potential causal pathways by which policy making and implementation are influenced. It supplements concepts of structural governance linkages, which are common in the existing literature, with attention to agent-oriented actor linkages. The article offers a typology of governance and actor linkages that can be operationalized in empirical research. It discusses governance and actor linkages between policy making within the Convention on Long-Range Transboundary Air Pollution and the European Union. The paper argues that research on international environmental cooperation would benefit from greater empirical attention to linkages in a context of a multitude of connected governance and actor linkages.
The Oslo-Potsdam Solution to Measuring Regime Effectiveness: Critique, Response, and the Road Ahead
Authors: Hovi Jon , Sprinz Detlef F. , Underdal Arild
Published: October 2003

In international regimes research, one of the most important questions is how effective regimes are in delivering what they were established and designed to achieve. Perhaps the most explicit and rigorous formula for measuring regime effectiveness is the so-called Oslo-Potsdam solution. This formula has recently been criticized by Oran Young, himself one of the founding fathers of regime analysis. The present article reviews and responds to his critique and provides several extensions of the Oslo-Potsdam solution. Our response may be summarized in three points. First, we recognize that difficult problems remain unsolved. Second, we argue that for some of the most profound problems there is no escape; we need to engage in counterfactual reasoning, and we need some notion of the “best” solution achievable (such as the “collective optimum”). Finally, we would welcome efforts to further develop and refine the Oslo-Potsdam formula as well as alternative approaches.
DE-CENTRING RELIGIOUS SINGULARITY: THE GLOBALIZATION OF CHRISTIANITY AS A CASE IN POINT
Authors: Beyer Peter
Published: October 2003

Recent scholarship in religious studies has again questioned the validity of the idea of religions and of certain religions in particular, such as Hinduism. The debate raises the question of how any religion, including Christianity, can be thought of or lived as a singular identity in today's world. While this is a very broad question with a very long history, this presentation translates the matter into one of the relation between globalization, localization, and religion. It argues that in the more recent phases of historical globalization, the issue of unity, identity, and singularity in religion has fundamentally changed from one which depends on a hierarchical and core/periphery distribution of defining power to one in which singularity is the observed or recognized outcome of multiple localizations of a contested and global model. Thus the singularity of a religion is not just the product of uneven power relations between those who get to define and those who do not, but rather the internally and externally observed synthesis of plural glocalizations. This abstract thesis is illustrated on hand of an examination of developments in global Christianity especially in the 19th and 20th centuries.
THE EVOLUTION OF RELIGIONS
Authors: Wunn Ina
Published: October 2003

The article contributes to a theoretical framework for a theory that describes and explains the distribution and development of the various religions from a genetical and historical point of view. While religious evolution until now has been understood as a process of progress, the theory outlined in this paper focuses on the biological Theory of Evolution in order to direct the attention to the main characteristics of natural evolutionary processes. By drawing parallels between biological and religious evolution the evolution of religions is described as the adaptive modification of religions throughout history. After discussing the question of a natural systematic unit in the world of religions, the different means of evolutionary processes are investigated. As a result, a theory is presented that understands the development of religions in a way which explains their recent phenotype as well as their modifications during history.
"SCIENCE" VS. "RELIGION" IN CLASSICAL AYURVEDA
Authors: Engler Steven
Published: October 2003

This paper evaluates claims that classical Ayurveda was scientific, in a modern western sense, and that the many religious and magical elements found in the texts were all either stale Vedic remnants or later brahminic impositions. It argues (1) that Ayurveda did not manifest standard criteria of "science" (e.g., materialism, empirical observation, experimentation, falsification, quantification, or a developed conception of proof) and (2) that Vedic aspects of the classical texts are too central to be considered inauthentic or marginal. These points suggest that attempting to apply the modern western categories of "science" and "religion" to ancient South Asian medical texts at best obscures more important issues and, at worst, imports inappropriate orientalist assumptions. Having set aside the distraction of "science" vs. "religion" in classical Ayurveda, the paper finds support for claims that brahminic elements were later additions to the texts. It concludes by arguing that this is best explained not in terms of a conceptual tension between religion and science but in terms of social and economic tensions between physicians and brahmins.
Identifying effects of toe clipping on anuran return rates: the importance of statistical power
Authors: McCarthy Michael , Parris Kirsten
Published: October 2003

Toe clipping is a common method of marking anurans for population studies. We re-analysed data from four published studies investigating the relationship between return rate and number of toes clipped for three anuran species: Bufo fowleri, Crinia signifera and Hyla labialis. Although these studies claimed contradictory results, a re-analysis of the data with proper attention to statistical power demonstrated a statistically significant decline of 6-18% in the probability of return for each toe removed after the first, in three of the four studies examined. The probability that the fourth study would detect a statistically significant effect of toe clipping was low unless the size of the effect was overwhelming. These results provide consistent evidence that toe clipping decreases the return rate of marked anurans, and demonstrates the importance of considering statistical power during data analysis. Use of toe clipping for mark-recapture studies may produce estimates of population parameters that are biased by the same magnitude as the return rates, unless researchers control for the effect of this marking method.
Male reproductive cycle of the water frog Rana epeirotica in northwestern Greece
Authors: Kyriakopoulou-Sklavounou  , Tsiora
Published: October 2003

The reproductive cycle of male Rana epeirotica was studied with emphasis on spermatogenetic activity and changes in the weights of testis, fat body and liver. The spermatogenesis of Rana epeirotica is of the potentially continuous type. Significant seasonal variations were observed in testis, fat body and liver weight. The seasonal variation of testis weight showed a good agreement with the spermatogenetic cycle. The reduction of fat body weight during the pre-hibernating period was attributed to mobilizing of lipids to other body parts or to transformation into other metabolites. The significant decrease of liver weight in the dormant period indicates that this frog consumes mainly glycogen during wintering. The greatest decrease of fat body and liver weight in May results from the intensive activities related to reproduction and maintenance.
Scanning electron microscopic studies on spermatozoa of anurans from India and Sri Lanka
Authors: Joshy Hareesh , Kuramoto Mitsuru
Published: October 2003

The shape and size of spermatozoa of 11 frog species from India and Sri Lanka were examined by scanning electron microscopy. The spermatozoa of the genera Limnonectes and Euphlyctis were of the generalized type with a thick sperm head and a thin tail, whereas Indirana semipalmata had peculiar spermatozoa with a densely coiled sperm head and a thick tail. Rhacophorus microtympanum is likely to belong to the genus Philautus from sperm morphology. The spermatozoa of Microhyla ornata and Ramanella obscura were very similar, with a cone-shaped sperm head and a thin tail.
Reproductive behaviour of the Chinhai Salamander (Echinotriton chinhaiensis) (Caudata: Salamandridae)
Authors: Sparreboom Max , Fei Liang , Xie Feng
Published: October 2003

The Chinhai Salamander, Echinotriton chinhaiensis, mates on land. The male of a courting pair marks a trail by a mucous excretion from his cloaca. The pair follows an ellipsoid track during which manoeuvre a spermatophore is deposited. Partners align their bodies such that the female is led over the spermatophore. Clasping was not observed. The female traces the spermatophore with her cloaca through shifting movements with the pelvic region. A male may deposit several spermatophores on one evening. The courtship is compared to that in the genus Tylototriton.
Annual cycle of the speckle pattern on the carapace of immature hawksbill turtles (Eretmochelys imbricata) in Cuba
Authors: Kobayashi Mari
Published: October 2003

The black speckles in the carapace surface pattern of the hawksbill turtle go through two periods of development: one is the formation period and the other is a period of less formation, and these periods occur once a year. The results of this study show that these cycles have nothing to do with genetics or the growth of the shell. These cycles are highly correlated with the changes in the water surface temperature in the sea near Cuba. The black-speckle formation period falls before and after March, which is the dry season (a low-temperature period), while the amber color area tends to take shape during the wet season (high-temperature) in Cuba.
Responses to prey and plant chemicals by three iguanian lizards: relationship to plants in the diet
Authors: Espinoza Robert , Habegger Jason , Cooper William
Published: October 2003

We examined responses of three iguanian lizards, the phrynosomatid Sceloporus poinsettii and the tropidurids Tropidurus hispidus and Phymaturus punae, to prey chemicals and plant chemicals. When chemical stimuli were presented on cotton swabs or on ceramic tiles, neither S. poinsettii nor T. hispidus discriminated among prey, plant, and control stimuli. In contrast, an individual of P. punae discriminated both prey and plant chemicals from control stimuli in swab tests, typically biting swabs bearing prey or plant cues. These findings are consistent with the hypothesis that plant chemical discrimination evolves in herbivorous iguanians such as P. punae. Sceloporus poinsettii, which appears to be entirely insectivorous at some times, but eats substantial quantities of flowers at others, did not discriminate among the stimuli. Because all previously tested herbivores and omnivores responded strongly to prey and plant chemicals, the absence of such discriminations by S. poinsettii raises questions about the degree and regularity of herbivory that may be required for plant chemical discrimination to evolve. The results extend the absence of prey chemical discrimination in ambush foragers to T. hispidus.
Movements, distribution pattern and density in a population of Salamandra atra aurorae (Caudata: Salamandridae)
Authors: Bonato Lucio , Fracasso Giancarlo
Published: October 2003

Spatial behaviour of Salamandra atra aurorae Trevisan, 1982, was investigated by a capture-recapture program during a whole season of activity. Salamanders changed their behaviour with growth: while juveniles usually dispersed on the ground, adults showed a strong fidelity to a limited area, a few square metres wide, also from year to year. Each individual frequently changed its diurnal refuge over the course of the whole activity season, choosing among a large variety of potential shelters. The distribution pattern of the home ranges was slightly aggregated, irrespective of age and sex. Under the assumptions of a closed population and an equal catchability among individuals, a density of 475 (±184; 95% confidence interval) salamanders per hectare was estimated in a mature and quite open wood, whereas a density of 97 (±23; 95% confidence interval) salamanders per hectare was estimated in a thicker wood.
Susceptibility of frog (Rana temporaria) and toad (Bufo bufo) eggs to invasion by Saprolegnia
Authors: Griffiths Richard , Robinson Jim , Jeffries Peter
Published: October 2003

Infections of amphibian eggs sometimes cause catastrophic losses of reproductive effort, but susceptibility to infection in different species is poorly understood. Using laboratory trials we showed that direct hyphal invasion of adjacent eggs by Saprolegnia caused a higher incidence of infection than invasion by zoospores. Moreover, we observed that dead eggs were much more readily colonized than live eggs when challenged with zoospores from two strains of Saprolegnia. The two strains were equally effective in causing infections of Rana temporaria eggs, but differed in their ability to infect eggs of Bufo bufo. In live R. temporaria eggs, early stages (pre-tailbud) were more frequently infected by hyphal invasion than later stages by the same strains, suggesting that susceptibility to infection decreases as development proceeds.
A new species of Elachistocleis (Anura: Microhylidae) from the Andean Yungas of Argentina, with comments on the Elachistocleis ovalis - E. bicolor controversy
Authors: Ferrari Liliana , Vaira Marcos , Lavilla
Published: October 2003

Elachistocleis skotogaster spec. nov. is described from the Andean Yungas of Argentina. It is unique in the genus in having belly and legs densely spotted with brown, an uniformly dark brown dorsal mottled with black, absence of a light vertebral strip, a fold behind the mouth but not a postcommisural gland. Its natural history and advertisement call are briefly noted. Elachistocleis ovalis and E. bicolor are considered different species, and Buenos Aires, Argentina, is established as type locality for the latter one. Se describe Elachistocleis skotogaster n. sp. de las Yungas andinas de Argentina. Se diferencia de las restantes especies del género por presentar vientre y región inferior de los miembros posteriores densamente punteada de castaño, la región dorsal castaño oscuro, punteada en negro, sin banda vertebral clara, y el área por detrás de la boca con un pliegue pero sin glándula postcomisural. Elachistocleis ovalis y E. bicolor son consideradas especies diferentes y se establece Buenos Aires, Argentina, como localidad tipo de esta última.
A new frog of the genus Mantidactylus from the rainforests of north-eastern Madagascar, and its karyological affinities
Authors: Odierna Gaetano , Vences Miguel , Aprea Gennaro , Andreone Franco
Published: October 2003

We describe a new species of the genus Mantidactylus found during field inventories in the north-eastern rainforests of Madagascar. Mantidactylus salegy sp. n. reaches a snout-vent length of 45-50 mm, has evident dorsolateral ridges and whitish spots on the upper jaws (mainly in females). The vocal sacs in males are distinctly visible and paired subgular, without strongly inflatable areas recognizable between the blackish lateral skin flaps on the throat. This frog exhibits a mosaic of characters previously thought to be typical for either the subgenera Gephyromantis or Phylacomantis. Therefore, it is a crucial discovery towards better understanding of the relationships between the taxa included in these two subgenera, supporting previous molecular results which indicated their paraphyly. The call of M. salegy consists of a rapid series of 8-11 rattling notes emitted at 1000-3500 Hz. We also provide karyological data for M. salegy, and for several related species, M. granulatus, M. leucomaculatus, M. moseri, M. redimitus, M. zavona, and M. pseudoasper (attributed to the subgenus Phylacomantis) and M. luteus (subgenus Gephyromantis). In terms of general chromosome morphology and structure, NOR localisation and heterochromatin characteristics, M. salegy shows similarities to M. redimitus, M. zavona and M. leucomaculatus, all included within Phylacomantis. Our data confirm that NOR position is a phylogenetically informative character.
Two new species of the Boophis mandraka complex (Anura, Mantellidae) from the Andasibe region in eastern Madagascar
Authors: Glaw Frank , Vences Miguel , Vallan Denis
Published: October 2003

The treefrog genus Boophis is represented in Madagascar by 50 described species. In this paper we describe two new cryptic species: B. liami sp. nov. and B. solomaso sp. nov. are similar to B. mandraka in morphology and colouration, but are clearly different in bioacoustic and genetic characters. The existence of many sibling species within Boophis shows the importance of detailed studies to clarify the distribution and the ecological requirements of the species in this genus. Les anoures arboricoles du genre Boophis sont représentés à Madagascar par 50 espèces. Dans cet article nous décrivons deux nouvelles espèces cryptiques : B. liami sp. nov. et B. solomaso sp. nov. ressemblent a B. mandraka par la coloration et la morphologie, mais ce distinguent clairement par la bioacoustique et le caractères génétiques. L'existence de beaucoup de "sibling species" dans le genre Boophis montre l'importance des études détailles pour qu'on puisse clarifier les questions concernant la répartition et les demandes écologiques des espèces de ce genre.
Phylogeography of the genus Xenopus in southern Africa
Authors: Channing  , Measey
Published: October 2003

Xenopus laevis (Daudin, 1802) has been the subject of numerous studies but is taxonomically poorly understood. Part of the Cytochrome b gene in mitochondrial DNA was sequenced from 50 individual Xenopus from three currently recognised species, taken from 28 localities in southern Africa, and from an outgroup of two West African X. epitropicalis. Phylogenetic analyses of these data reveal well-supported tree structure, demonstrating three clades within what is currently regarded as X. laevis : X. l. laevis from the Cape, X. l. petersii, and X. l. laevis from further north. This evidence agrees with other studies (on morphology, call and parasite data) which suggest that what is currently regarded as X. laevis encompasses more than one species. Workers using Xenopus collected away from the Cape of South Africa are not safe in assuming that they are using X. laevis.
Digestive ecology of two omnivorous Canarian lizard species (Gallotia, Lacertidae)
Authors: Valido Alfredo , Nogales Manuel
Published: October 2003

Omnivorous endemic Canarian lacertids (Gallotia atlantica and G. galloti) do not present any specific digestive and physiological adaptations to herbivorous diet, compared to species and populations with a different degree of herbivory in the Canarian archipelago. The only characteristics that could be related to the type of diet were the number of cusps per tooth (between species) and the number of small stones contained in droppings (between species and populations). The rest of measured traits were correlated with lizard size and for this reason G. galloti has longer intestines, heavier stomachs and livers, more teeth and cusps, and longer gut passage. These data suggest that body size is a major determinant of the reliance on plant food (mainly fleshy fruits) in these lizards and facilitates mutualistic interactions with fleshy-fruited plant species.
Aggregation behaviour and movement patterns in the large-scaled girdled lizard, Cordylus macropholis
Authors: Mouton P. Le Fras , Nieuwoudt Cara , Flemming Alexander
Published: October 2003

Aggregation behaviour and movement patterns were studied in the large-scaled girdled lizard, Cordylus macropholis. The size of aggregations within Euphorbia caput-medusae plants ranged from one to 14 individuals. Aggregation was a year-round phenomenon and aggregations were generally larger during autumn/winter than during spring/summer. Most aggregations consisted of an adult pair together with a varying number of juveniles. Site fidelity was low, with females showing significantly higher site fidelity than males. Movement of individuals in and out of the marked population was high, with no sex differences. Females covered slightly greater distances than males outside the mating season, whereas males covered slightly greater distances than females within the mating season. The results suggest that aggregation behaviour and high degree of movement in C. macropholis are the result of competition for a limited plant resource. The results do not confirm differential movement patterns between the sexes.
Geographic variability and taxonomy of the nose-horned viper, Vipera ammodytes (L. 1758), in the central and eastern parts of the Balkans: A multivariate study
Authors: Džukić Georg , Tomović Ljiljana
Published: October 2003

A multivariate analyses of various morphological characters (morphometric, meristic and qualitative) of nose-horned viper (Vipera ammodytes) revealed a complex morphological differentiation of populations from the central and the eastern Balkan Peninsula. Analyses of quantitative data showed no clear morphological discrimination or well-defined taxonomical units. On the contrary, analyses of qualitative traits separated two discrete taxa in the analysed area. One, inhabiting the eastern and the southern part of the Balkans, includes samples from most parts of Bulgaria, Former Yugoslav Republic of Macedonia and south-eastern Serbia, whereas the other ranges from north-western Bulgaria through the main part of Serbia (except the south-east) to Montenegro.
Machine failure and its avoidance—what is tribology's contribution to effective maintenance of critical machinery?
Authors: Roylance B. J.
Published: October 2003

Following a brief historical overview of maintenance practice, the principles that govern tribological phenomena are summarized in terms of the issues involved in the upkeep and care of operating machinery. Condition-based and proactive maintenance strategies are identified in order to permit examination of the key tribological factors involved and what steps are being taken to assist in the implementation of good practices. Some of the issues to be faced when maintaining equipment in the aerospace, steel and pharmaceutical industries are highlighted as a basis for indicating ways in which the tribologist can further contribute to improving maintenance practice.
Analytical study of the extrusion of rectangular elastomeric seals for linear hydraulic actuators
Authors: Nikas G. K.
Published: October 2003

Rectangular elastomeric seals used on reciprocating piston rods in high-pressure hydraulic actuators often suffer from extrusion damage at the low-pressure side of the actuators. The extrusion takes place at the narrow clearance between the rod and the actuator, where the seal develops a ‘nip’ under conditions of high sealed pressure and/or high friction with the rod, which is amplified in the absence of a back-up ring. This form of strain can lead to permanent damage of the seal and impair the sealing performance of the system. This paper deals with the modelling of this kind of seal extrusion. Algebraic equations were developed to describe the shape and contact pressure of the extruded part of the seal with the rod. A study is presented about the effects of various operating parameters on the extent of seal extrusion in order to minimize the risks of damage. It was found that only the use of a back-up ring can adequately cancel the seal extrusion mechanism.
Torque loss in spur gears with interference
Authors: Spiegelberg C , Christie M
Published: October 2003

Gears with interference (zero backlash) are used in robots and other precision equipment. The reason for using interference gearing is to improve positioning and motion control. It is then also desirable to compensate for the friction losses and therefore it is important to model the friction losses accurately. In this paper, results from a model for simulating spur gears with interference are compared with results from a test rig for spur gears with interference. FZG gears are used both in the test rig and in the simulations. Brief descriptions of the test rig and the simulation model are given in the paper; more thorough descriptions can be found in studies by Hedström and Kårhammar and by Spiegelberg, Andersson and Sellgren respectively. There is also a description of the measurements and the procedure of making them. The aim of this paper is to compare the results from the test rig with the results from the simulation model and to analyse the results from the test rig.

The results show that the simulated torque loss corresponds well with the measured torque loss within the range of the test rig. The results from both the test rig and the simulation model show that there are large variations in the frictional torque during one mesh of a gear tooth. The loss increases with the number of contact points and the lowest loss is found when a driving gear flank passes the pitch point. The overall efficiency decreases when the mesh force increases and the lowest efficiency readings are found when a combination of high mesh force and low load is applied.
Isoviscous elastohydrodynamic lubrication of circular point contacts with particular reference to metal-on-metal hip implants
Authors: Jalali- Vahid D , Jin Z. M. , Dowson D
Published: October 2003

A full numerical analysis of elastohydrodynamic lubrication (EHL) of circular point contacts was carried out in the present study under isoviscous conditions with particular reference to metal-on-metal artificial hip joints, using a modified Newton-Raphson method. It was found to be possible to incorporate directly the physiological conditions, representative of typical metal-on-metal hip implants under in-vivo walking or in-vitro simulator testing, in the present numerical solutions. The predicted minimum and central film thicknesses were compared favourably with those estimated from various formulae available in the literature. In particular, it was shown that both the minimum and the central film thickness expressions derived by Hamrock and Dowson were reasonably accurate for all the conditions considered in the present study.
Versatility of the Titanium(IV)–Porphyrin Reagent for Determining Hydrogen Peroxide
Authors: Takamura Kiyoko , Matsubara Chiyo
Published: October 2003

Hydrogen peroxide has been an important analyte in many fields for many years. The Ti–TPyP reagent, i.e., an acidic aqueous solution of oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(IV) complex, was developed as a highly sensitive spectrophotometric reagent for determining traces of hydrogen peroxide. Following the addition of hydrogen peroxide to the reagent, the absorbance at 432 nm decreased and a new peak appeared at 450 nm (the Soret band) accompanied by the consumption of the complex and the formation of its monoperoxo complex, respectively. The degrees of the absorbance changes were found to be proportional to the hydrogen peroxide concentration with the apparent molar absorptivities of 1.9 × 105 (432 nm) and 1.1 × 105 (450 nm) M−1 cm−1 (1 M = 1 mol dm−3). Both values are much larger than those obtained by the conventional analysis methods. Based on these facts, the determination of hydrogen peroxide was made by a batch method and a flow injection analysis (FIA) method with the detection limits of 25 pmol and 0.5 pmol per test, respectively. In this account, the Ti–TPyP reagent is assessed for determining hydrogen peroxide in rainwater and in the atmosphere, and for determining several components in foods and biofluids mediated by appropriate oxidase enzymes, to demonstrate its potential for a broad range of applications.
PdII-Catalyzed Reaction of Phenols with Propiolic Esters. A Single-Step Synthesis of Coumarins
Authors: Kitamura Tsugio , Yamamoto Kiyomi , Kotani Masashi , Oyamada Juzo , Jia Chengguo , Fujiwara Yuzo
Published: October 2003

The intermolecular reaction of phenols with propiolic esters in TFA in the presence of a Pd(OAc)2 catalyst, affording coumarin derivatives, is described. An exclusive formation of 5,6,7-trimethoxy-4-phenylcoumarin was observed in the reaction of 3,4,5-trimethoxyphenol and ethyl phenylpropiolate with a catalytic amount of Pd(OAc)2. The reaction in the absence of Pd(OAc)2 did not give any coumarin at all. Coumarin derivatives were obtained in high yields in the cases of electron-rich phenols, such as 3,4-methylenedioxyphenol, 3-methoxyphenol, 2-naphthol, and 3,5-dimethoxyphenol. Furthermore, the reaction of some phenols with various 2-alkynoates or with diethyl acetylenedicarboxylate gave the corresponding coumarins in good-to-high yields.
Conformational Analysis of (±)-(1,1′-Biindene)-3,3′-dione, 2,2′,3,3′-Tetrahydro-(1,1′-binaphthalene)-4,4′(1H,1′H)-dione, and (1,1′-Bibenzosuberene)-5,5′-dione
Authors: Lam Yulin , Ma Ngai Ling , Huang Hsing-Hua , Liang Eping
Published: October 2003

The dipole moments of (±)-(1,1′-biindene)-3,3′-dione 1, (±)-2,2′,3,3′-tetrahydro-(1,1′-binaphthalene)-4,4′(1H,1′H)-dione 2, and (±)-(1,1′-bibenzosuberene)-5,5′-dione 3 in carbon tetrachloride and benzene were measured over a range of temperatures. Analyses of the relative permittivity data in carbon tetrachloride and benzene showed that at 25 °C, 1 exists predominantly in the gauche conformation, whilst 2 and 3 favor the trans form. The experimentally derived values of the energy difference between the gauche and trans rotamers and the gauche/trans population quotient were compared with values predicted by molecular-orbital calculations. The crystal and molecular structures of 2 and 3 were determined by single-crystal X-ray diffraction methods. Both compounds exist in the trans conformation in the solid-state. Dynamic 1H NMR was employed to 3 in order to determine the activation parameters for the barriers to rotation in solution.
Electronic Structure of Sulfanenitriles
Authors: Bharatam Prasad V , Amita  , Kumar P Senthil
Published: October 2003

Ab initio calculations have been carried out to analyze the electronic structure of organosulfur compounds with S≡N. The electronic structures of R3S≡N, R(O)S≡N, and RS≡N have been compared. The calculations suggest that the S–N interactions should be taken as a hybrid of the S≡N triple bond and the S+–N− single bond. The balance between the two resonating structures shift towards a S≡N triple-bonded arrangement with an increase in the electronegativity of substituents on sulfur. The strength of the Lewis basicity of sulfanenitriles has been estimated by studying their proton affinities and the complexation energies with BH3. On the potential energy surface of H3S≡N, this hypervalent compound has been shown to be a high-energy local minimum; although its 1,2-H shift isomers are all more stable, the barrier for the 1,2-shift is very high.
Decomposition of Trichlorobenzene Isomers by Co-Grinding with CaO
Authors: Tanaka Yasumitsu , Zhang Qiwu , Mizukami Koichi , Saito Fumio
Published: October 2003

Two types of trichlorobenzene (TCB) isomers, 1,2,3- and 1,3,5-, were subjected to grinding in air with CaO in a planetary ball mill to investigate their decomposition phenomena. Results showed that TCB samples were decomposed by the co-grinding to form calcium chloride hydrate and amorphous carbon as the main products, with other minor compositions such as carbon dioxide and water. There was no significant difference in the decomposition phenomena between the two isomers. Radicals were generated during the decomposition process, predominantly due to the rupture of C–Cl bonds in the molecule. Supported by the simulation data, we concluded that dehydrochlorination during TCB decomposition process to form hydrochloride (HCl, further to CaOHCl) exhibited the lower possibility, suggesting dechlorination rather than dehydrochlorination as the plausible decomposition pathway.
Lowest Electronically Excited Triplet States of 1,2,4,5-Tetracyanobenzene and Tetracyanopyrazine by Matrix-Isolation Infrared Spectroscopy Combined with a Density-Functional-Theory Calculation
Authors: Akai Nobuyuki , Miura Isamu , Kudoh Satoshi , Shigehara Kiyotaka , Nakata Munetaka
Published: October 2003

The infrared spectra of photoexcited transient species produced during UV irradiation from 1,2,4,5-tetracyanobenzene (TCNB) and tetracyanopyrazine (TCNP) in low-temperature argon matrices were measured with a Fourier-transform infrared (FTIR) spectrophotometer. The produced transient species were identified as the lowest electronically excited triplet states, T1, by a comparison of the observed infrared spectra with the calculated spectral patterns obtained by the hybrid density-functional-theory (DFT) method. The vibrational wavenumbers of the asymmetric C≡N stretching modes in the T1 states were found to be shifted to the low-wavenumber side by about 150 cm−1, indicating that the bonds of the cyano groups, –C≡N, in the T1 states are close to cumulative double bonds, C=C=N. This observation is supported by calculations of the optimized geometrical structures and the Mulliken spin density obtained by the DFT method.
Structure and Physical Properties of Low-Dimensional Molecular Conductors, [PXX][FeIII(Pc)(CN)2] and [PXX][CoIII(Pc)(CN)2] (PXX = peri-xanthenoxanthene, Pc = phthalocyaninato)
Authors: Matsuda Masaki , Asari Takehiro , Naito Toshio , Inabe Tamotsu , Hanasaki Noriaki , Tajima Hiroyuki
Published: October 2003

A novel low-dimensional molecular conductor, [PXX][FeIII(Pc)(CN)2], has been synthesized. This salt contains the magnetic FeIII ion (S = 1/2), and is isomorphous with [PXX][CoIII(Pc)(CN)2] which includes the non-magnetic CoIII ion. In both salts, the [MIII(Pc)(CN)2] (M = Fe or Co) units form a two-leg ladder chain. The two salts exhibit a similar temperature dependence of the thermoelectric power and a similar reflectance spectrum. The FeIII salt shows semiconducting behavior in its electrical resistivity over the temperature range measured, while the isomorphous CoIII salt exhibits metallic behavior in its resistivity above 100 K. The difference in the transport properties between the two salts suggests that the conduction electrons in the FeIII salt are seriously scattered by the local magnetic moment. Spontaneous magnetization is observed below 8 K in the FeIII salt. Upon applying a magnetic field, the resistivity of the FeIII salt drastically decreases below 50 K. The decrease in the resistivity is highly anisotropic to the field orientation. The field orientation dependence is highly consistent with the g-tensor anisotropy in the [FeIII(Pc)(CN)2] unit, suggesting that the negative magnetoresistance originates from the large π–d interaction self-contained in the [FeIII(Pc)(CN)2] unit.
Synthesis and Structural Characterization of 2,5-Bis(N-aryliminomethyl)pyrrolyl Complexes of Aluminum
Authors: Matsuo Yutaka , Tsurugi Hayato , Yamagata Tsuneaki , Tani Kazuhide , Mashima Kazushi
Published: October 2003

Reaction of tridentate ligands, 2,5-bis(N-aryliminomethyl)pyrroles (1a–e), with 1 equiv of AlMe3 in toluene afforded aluminum dimethyl complexes, AlMe2[2,5-bis(N-aryliminomethyl)pyrrolyl] (2a–e) with the release of one equiv of methane. In solution the aluminum complexes 2a–e showed Cs-symmetry as characterized by their 1H NMR spectra, while in solid the geometry around the Al atom as crystallographically determined for 2a and 2b was found to a tetrahedral by an amido nitrogen atom of the pyrrolyl anion, a nitrogen atom of one of two imino groups and two methyl groups. The aluminum complex 2e upon activated by one equiv of B(C6F5)3 became a catalyst for ethylene polymerization (Activity = 80 g-PE/mol-cat·h).
Syntheses and Structural Analyses of 1,3-Diphenyldisiloxanes as a Building Block of Silsesquioxanes
Authors: Seto Isamu , Gunji Takahiro , Kumagai Kaoru , Arimitsu Koji , Abe Yoshimoto
Published: October 2003

Syntheses of novel 1,3-diphenyldisiloxanes were investigated. 1,1,3,3-Tetrachloro-1,3-diphenyldisiloxane (1) and 1,1,3,3-tetraisocyanato-1,3-diphenyldisiloxane (2) were obtained by vapor-phase hydrolytic condensation of trichloro(phenyl)silane and triisocyanato(phenyl)silane, respectively. The reactions of 1 with 2-propanol, t-butyl alcohol, and diethylamine provided 1,1,3,3-tetraisopropoxy-1,3-diphenyldisiloxane (3), 1,3-di-t-butoxy-1,3-dichloro-1,3-diphenyldisiloxane (5a), and 1,1,3,3-tetrakis(diethylamino)-1,3-diphenyldisiloxane (6), respectively. 1,3-Diisocyanato-1,3-diisopropoxy-1,3-diphenyldisiloxane (4) and 1,3-di-t-butoxy-1,3-diisocyanato-1,3-diphenyldisiloxane (5b) were synthesized by the reactions of 2 with 2-propanol and with t-butyl alcohol, respectively. Hydrolysis of 5a or 5b afforded 1,3-di-t-butoxy-1,3-diphenyldisiloxane-1,3-diol (7). 1,3-Diphenyldisiloxane-1,1,3,3-tetrol (8) was isolated from the hydrolysis of 1. A single crystal X-ray diffraction of 8 showed that four hydroxy groups are facing each other to form a ladder-type network by the intermolecular hydrogen bondings.