bluuebunny/crossref_metadata_2025_split huggingface dataset:
Learning to time capacity expansions: an empirical analysis of the worldwide petrochemical industry, 1975–95
Authors: Henderson James , Cool Karel 
Published: March 2003

AbstractThis paper examines how firms may learn to better time their capacity expansion decisions through their own and their rivals' past experiences. A review of the literature shows that there may be several reasons for firms to bunch their capacity additions or ‘hop on an investment bandwagon.’ These reasons include coordinating through maintaining market shares, information effects, and decision‐making biases. Given the substantial evidence of organizational learning, firms may be expected to improve their timing skills of capacity additions through their previous capacity expansion experience. Hypotheses are developed both for proprietary learning and learning at the industry level, and for forgetting. These hypotheses are tested on a database consisting of 72 companies operating in the petrochemicals industry in the United States, Europe, and Japan from 1975 to 1995. The results indicate that learning in timing capacity expansion decisions comes primarily from within firms through an accumulation of their poor outcomes. However, this timing skill is far more apparent in greenfield than incremental expansion decisions. Copyright © 2003 John Wiley & Sons, Ltd.
Prior performance characteristics of related and unrelated acquirers
Authors: Park Choelsoon 
Published: March 2003

AbstractIn the diversification literature, studies, particularly those using accounting‐based performance measures, have found that related diversifiers are more profitable and that related diversifiers are in more profitable industries than unrelated diversifiers. Due to the very nature of these studies based on cross‐sectional data, however, the causal relationship between diversification strategy and performance was not clear. This paper focuses on a single event of a large acquisition, which enables us to better identify the sequential relationships between prior firm profitability, prior industry profitability, and subsequent acquisition strategies. By doing so, this paper makes clearer the causal relationships between firm profitability, industry profitability, and acquisition strategies. Copyright © 2003 John Wiley & Sons, Ltd.
Thread transparency in information flow middleware
Authors: Koster Rainer , Black Andrew P. , Huang Jie , Walpole Jonathan , Pu Calton 
Published: March 2003

AbstractApplications that process continuous information flows are challenging to write because the application programmer must deal with flow‐specific concurrency and timing requirements, necessitating the explicit management of threads, synchronization, scheduling and timing. We believe that middleware can ease this burden, but many middleware platforms do not match the structure of these applications, because they focus on control‐flow centric interaction models such as remote method invocation. Indeed, they abstract away from the very things that the information‐flow centric programmer must control.This paper describes Infopipes—a new high‐level abstraction for information flow applications—and a middleware framework that supports them. Infopipes handle the complexities associated with control flow and multi‐threading, relieving the programmer of these tasks. Starting from a high‐level description of an information flow pipeline, the framework determines which parts of a pipeline require separate threads or coroutines, and handles synchronization transparently to the application programmer. The framework also gives the programmer the freedom to write or reuse components in a passive style, even though the configuration will actually require the use of a thread or coroutine. Conversely, it is possible to write a component using a thread and know that the thread will be eliminated if it is not needed in a pipeline. This allows the most appropriate programming model to be chosen for a given task, and existing code to be reused irrespective of its activity model. Copyright © 2003 John Wiley & Sons, Ltd.
Access control and trust in the use of widely distributed services
Authors: Bacon Jean , Moody Ken , Yao Walt 
Published: March 2003

AbstractOASIS is a role‐based access control (RBAC) architecture for achieving secure interoperation of independently managed services in an open, distributed environment. OASIS differs from other RBAC schemes in a number of ways: role management is decentralized, roles are parametrized, roles are activated within sessions and privileges are not delegated. OASIS depends on an active middleware platform to notify services of any relevant changes in their environment.Services define roles and establish formally specified policy for role activation and service use (authorization); users must present the required credentials and satisfy specified constraints in order to activate a role or invoke a service. The membership rule of a role indicates which of the role activation conditions must remain true while the role is active. A role is deactivated immediately if any of the conditions of the membership rule associated with its activation become false.OASIS introduces the notion of appointment, whereby being active in certain roles carries the privilege of issuing appointment certificates to other users. Appointment certificates capture the notion of long‐lived credentials such as academic and professional qualification or membership of an organization. The role activation conditions of a service may include appointment certificates, prerequisite roles and environmental constraints.The role activation and authorization policies of services within an administrative domain need not embody role hierarchies nor enforce privilege delegation. But OASIS is sufficiently flexible to capture such notions, through prerequisite roles and appointments, if they are required within an application domain.We define the model and architecture and discuss engineering details, including security issues. We illustrate how an OASIS session can span multiple domains and we propose a minimal infrastructure to enable widely distributed, independently developed services to enter into agreements to respect each other's credentials. In a multi‐domain system access control policy may come from multiple sources and must be expressed, enforced and managed. In order to respond to changing relationships between organizations it should be easy to allow role holders in one domain to obtain privileges in another. Our approach to policy and meta‐policy management is described.We speculate on a further extension to mutually unknown, and therefore untrusted, parties. Each party will accumulate audit certificates which embody its interaction history and which may form the basis of a web of trust. Copyright © 2003 John Wiley & Sons, Ltd.
The CORBA Activity Service Framework for supporting extended transactions
Authors: Houston I. , Little M. C. , Robinson I. , Shrivastava S. K. , Wheater S. M. 
Published: March 2003

AbstractAlthough it has long been realized that ACID (atomicity, consistency, isolation, durability) transactions by themselves are not adequate for structuring long‐lived applications and much research work has been done on developing specific extended transaction models, no middleware support for building extended transactions is currently available and the situation remains that a programmer often has to develop application specific mechanisms. The CORBA Activity Service Framework described in this paper is a way out of this situation. The design of the service is based on the insight that the various extended transaction models can be supported by providing a general purpose event signalling mechanism that can be programmed to enable activities—application specific units of computations—to coordinate each other in a manner prescribed by the model under consideration. The different extended transaction models can be mapped onto specific implementations of this framework, permitting such transactions to span a network of systems connected indirectly by some distribution infrastructure. The framework described in this paper is an overview of the OMG's (Object Management Group) Additional Structuring Mechanisms for the OTS standard. Through a number of examples the paper shows that the framework has the flexibility to support a wide variety of extended transaction models. Although the framework is presented here in CORBA specific terms, the main ideas are sufficiently general, so that it should be possible to use them in conjunction with other middleware. Copyright © 2003 John Wiley & Sons, Ltd.
Plant conservation ecology for management and restoration of riparian habitats of lowland Japan
Authors: Washitani I. 
Published: March 2003

AbstractConservation ecology is a new paradigm of ecology that aims at scientific contributions to maintaining earth's biodiversity and is committed to ecosystem management indispensable to intergenerational long‐term sustainability. Population ecology plays a central role in conservation ecology. Persistence of the metapopulation rather than that of each local population should be pursued in species conservation management. Biological interactions essential to reproduction and soil seed bank components of the population should be investigated and applied to planning for the conservation of a plant population. Gravelly floodplains and moist tall grasslands are among typical riparian habitats containing many threatened plants in Japan. These riparian habitats are now subjected not only to heavy fragmentation but also to intensive invasion of highly competitive alien (nonnative) plants. Extreme habitat isolation may result in reproductive failure or fertility selection in a plant population without pollinators, as exemplified by a nature reserve population of Primula sieboldii. Biological invasions, which are facilitated by extensive changes in the river environment including decreased seasonal flooding, abandonment of traditional vegetation management, eutrophication, and extensive clearing of the land for recreational use, threaten endemic riparian species. To preserve safe sites and growing conditions for threatened plants such as Aster kantoensis, active management to suppress the dominance of alien invader plants is necessary. Population management and habitat restoration should be based on sound information on the population ecology of both threatened and alien invader plants, designed as an ecological experiment to clarify effective ways for management.
Modeling incomplete sterility in a sterile release program: interactions with other factors
Authors: Barclay H. J. 
Published: March 2003

AbstractModels were constructed for control of a pest species by the release of sterile insects and these models explored the consequences of incomplete sterility. This feature was then coupled with the lack of competitive ability of released insects, the immigration of insects from outside the control area, and the mode of population regulation (density independent vs. density dependent). Using the density‐independent models, it was seen that the limits on residual fertility of treated insects become much more stringent when incomplete sterilization is combined with a lack of competitive ability and immigration of insects into the control area. Strong density dependence in the system has a marked moderating effect on the requirements for sterility, competitive ability, and immigration. However, if the density‐independent limits on these factors are exceeded, then suppression is possible, but collapse of the pest population is impossible using sterile releases alone. Even suppression might not be satisfactory if these three detrimental factors are prominent. It is suggested that one remedy is the use of the sterile release method in combination with other control methods.
Non‐ant antiherbivore defenses before plant‐ant colonization in Macaranga myrmecophytes
Authors: Nomura M. , Itioka T. , Murase K. 
Published: March 2003

AbstractWe examined changes in the intensity of non‐ant defenses of three myrmecophytic Macaranga species before and after the initiation of symbiosis with ants in a Bornean dipterocarp forest. The intensities of non‐ant defenses at different growth stages of each Macaranga species were estimated by measuring the survival rate of larvae of the common cutworm, Spodoptera litura, when the larvae were fed on fresh leaves from seedlings (saplings) at three growth stages of each Macaranga species. In all species, the intensity of the non‐ant defenses when seedlings had not yet received symbiont foundress queens was significantly higher than that after ant defense was well established. These results support the hypothesis that myrmecophytic Macaranga may defend themselves sufficiently via non‐ant defenses before beginning symbiosis with ants and that the intensity of non‐ant defenses may decrease as the symbiont colony size increases. We suggest that, where the status of myrmecophytism changes as plant–ant colonies grow, the decrease in the intensity of non‐ant defenses which we detected after the establishment of ant colonies might generate an optimal allocation of metabolic cost to ant and non‐ant defenses under resource limitations. We also measured leaf toughness, which is considered to be one of the most important agents of non‐ant defenses against herbivorous insects, at different plant stages to assess its contribution to the change in the intensity of non‐ant defenses after ant colonization. However, we found no evidence that changes in leaf toughness have a significant effect on the change in balance of the two antiherbivory mechanisms.
A model of dominance and resource division among a group of animals of differing quality
Authors: Broom M. , Ruxton G. D. 
Published: March 2003

AbstractIndividuals of many species spend a large portion of their lives within groups of conspecifics. Within such groups, there can be considerable diversity in size and other traits, with some, perhaps larger or stronger, animals laying claim to a greater than fair share of available resources. We use the word quality as a single measure of individual animal phenotypes within such a group and develop a model of resource division through contests between animals of differing quality. We investigated the effect of varying environmental factors on the level of aggressiveness used in such contests and the division of resources among the group. A numerical example shows that maximum discriminations between individuals on the basis of quality occur for medium‐sized costs of aggressive encounters, but resources are divided more equitably at either extreme, when costs are either high or low.
Genetic status of fragmented populations of the Asian black bear Ursus thibetanus in western Japan
Authors: Saitoh T. , Ishibashi Y. , Kanamori H. , Kitahara E. 
Published: March 2003

AbstractThe population genetic status of the Asian black bear Ursus thibetanus in the western part of Japan was examined using microsatellite DNA markers. Although three fragmented populations have been recognized in this region, i.e., the western Chugoku (WC), eastern Chugoku (EC), and northern Kinki (NK) populations, it was recently pointed out that the NK population has also been divided into two subpopulations, the western (WNK) and the eastern (ENK) populations. We examined the genetic status of these four populations based on their heterozygosities and the genetic distances (FST) between them. The mean observed heterozygosity, i.e., genetic diversity, of the six microsatellite loci examined, was significantly lower in WC (0.272; n = 52) and WNK (0.311; n = 66) than that in ENK (0.445; n = 67), respectively. Reflecting geographic distances among populations, FST was higher between WC and WNK (0.244) and between WC and ENK (0.229) than that between WNK and ENK (0.066), respectively. There was also low but significant genetic differentiation between the two nearest populations (WNK and ENK). Although the status of EC was not conclusively determined because of its small sample size (n = 24), its genetic diversity seemed to be at a level similar to that of WC and WNK. These results suggest that WC, which is isolated from the others, has been losing genetic diversity, and that WNK, which had been thought to form a relatively large population together with ENK, might be isolated genetically from other populations. WNK, as well as WC and EC, should be conserved intensively.
Regular distribution of larvae and resource monopolization in the seed beetle Bruchidius dorsalis infesting seeds of the Japanese honey locust Gleditsia japonica
Authors: Shimada M. , Kurota H. , Toquenaga Y. 
Published: March 2003

AbstractLarvae of the wild multivoltine bruchid seed beetle Bruchidius dorsalis infest dry mature seeds of the Japanese honey locust Gleditsia japonica. The frequency distribution of B. dorsalis larvae per seed was examined in the laboratory. First, preliminary observation showed that the first‐instar B. dorsalis larva crawled from an eggshell and traveled in excess of 25 cm before boring into a seed. Larvae prefer boring into noninfested rather than infested seeds (indicated by a previous emergence hole). When a larva occasionally bored into a previously infested seed, it could emerge as an adult in spite of decreased body weight. Second, we conducted experiment 1 to investigate the frequency distributions of the number of boring holes per seed; results showed significantly regular distributions (a smaller variance than Poisson) in which most seeds had been bored by one larva. Third, we performed experiment 2 to examine the relationship between the initial number of larvae boring into one seed and the number of emerged adults and their body weight from a given seed. When we increased the ratio of egg density to seed abundance by experimental manipulation, multiple larvae (up to ten) could bore into one seed. However, only one adult emerged from each of about 85% seeds with multiple borings. When one adult emerged, the adult body weight was constant, independent of the initial number of larvae boring into the seed. Two adults occasionally emerged from one seed with a large difference in their body sizes. Even in this case, the larger adult was as heavy as that in a single emergence, although the other was significantly smaller (about 60%) than the normal size. These results show severe contest‐type competition among B. dorsalis larvae within one seed. The winner often monopolizes almost all the resources even though a part of the seed resource still remains.
Intraspecific competition in tadpoles of Rana arvalis: does it matter in nature? A field experiment
Authors: Loman J. 
Published: March 2003

AbstractTadpole growth and development are easily affected by intraspecific competition in tank experiments, provided treatment density is sufficiently high. Is this a phenomenon also observed in nature? A pond was divided into four tadpole‐proof sections. Each year for 8 years, all spawn laid by moorfrogs (Rana arvalis) in this pond was relocated to create relative spawn and tadpole densities of 1 : 4 : 1 : 4. No direct effect of the density manipulation on survival, tadpole size, and development and metamorph timing and size could be demonstrated. However, I also measured actual tadpole density during the time of development. Apart from the experimental density manipulation, this measure included effects of between‐year variation in amount of spawn, natural tadpole mortality, and pond drying (which concentrated the tadpoles by decreasing the area of the pond sections). Actual density had limited but significant effects on tadpole size and development. I suggest that density regulation, acting on the tadpole stage, may be present in the population but was of less short‐term importance than abiotic factors and, possibly, adult density regulation. Consequences of the findings for conservation are discussed.
Polymorphism of competition type and its genetics in Callosobruchus maculatus (Coleoptera: Bruchidae)
Authors: Takano M. , Toquenaga Y. , Fujii K. 
Published: March 2003

AbstractCallosobruchus maculatus has both contest and scramble competition strategies. The currently existing theoretical models using game theory suggest that the contest strategy should be selected for. However, most geographic strains of C. maculatus show scramble competition. We experimentally crossed the representative strains of contest and scramble. We expressed the degree of contest competition by a continuous value named the C‐value, which ranges from zero (pure scramble) to unity (pure contest). The competition types expressed in the C‐value were genetically additive. Their larval developmental rates were negatively correlated with C‐values. Multiple‐generation experiments of the mixed strains confirmed that there were no overwhelming advantages of contest over scramble type. Most of the mixed strains remained in the intermediate states. We discuss the results in terms of the resource size necessary for developmental success and developmental speed.
The Formation of Rhythmic Categories and Metric Priming
Authors: Desain Peter , Honing Henkjan 
Published: March 2003

Two experiments on categorical rhythm perception are reported, the object of which was to investigate how listeners perceive discrete rhythmic categories while listening to rhythms performed on a continuous time scale. This is studied by considering the space of all temporal patterns (all possible rhythms made up of three intervals) and how they, in perception, are partitioned into categories, ie where the boundaries of these categories are located. This process of categorisation is formalised as the mapping from the continuous space of a series of time intervals to a discrete, symbolic domain of integer-ratio sequences. The methodological framework uses concepts from mathematics and psychology (eg convexity and entropy) that allow precise characterisations of the empirical results. In the first experiment, twenty-nine participants performed an identification task with 66 rhythmic stimuli (a systematic sampling of the performance space). The results show that listeners do not just perceive the time intervals between onsets of sounds as placed in a homogeneous continuum. Instead, they can reliably identify rhythmic categories, as a chronotopic time clumping map reveals. In a second experiment, the effect of metric priming was studied by presenting the same stimuli but preceded with a duple or triple metre subdivision. It is shown that presenting patterns in the context of a metre has a large effect on rhythmic categorisation: the presence of a specific musical metre primes the perception of specific rhythmic patterns.
Structural dissection of alkaline‐denatured pepsin
Authors: Kamatari Yuji O. , Dobson Christopher M. , Konno Takashi 
Published: March 2003

AbstractIt has been established in a number of studies that the alkaline‐denatured state of pepsin (the IP state) is composed of a compact C‐terminal lobe and a largely unstructured N‐terminal lobe. In the present study, we have investigated the residual structure in the IP state in more detail, using limited proteolysis to isolate and characterize a tightly folded core region from this partially denatured pepsin. The isolated core region corresponds to the 141 C‐terminal residues of the pepsin molecule, which in the fully native state forms one of the two lobes of the structure. A comparative study using NMR and CD spectroscopy has revealed, however, that the N‐terminal lobe contributes a substantial amount of additional residual structure to the IP state of pepsin. CD spectra indicate in addition that significant nonnative α‐helical structure is present in the C‐terminal lobe of the structure when the N‐terminal lobe of pepsin is either unfolded or removed by proteolysis. This study demonstrates that the structure of pepsin in the IP state is significantly more complex than that of a fully folded C‐terminal lobe connected to an unstructured N‐terminal lobe.