bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative cognitive effects of bilateral subthalamic stimulation and subcutaneous continuous infusion of apomorphine in Parkinson's disease
Authors: Alegret Montse , Valldeoriola Francesc , Martí MaJosé , Pilleri Manuela , Junqué Carme , Rumià Jordi , Tolosa Eduardo
Published: July 2004

Bilateral subthalamic deep brain stimulation (STN‐DBS) and continuous subcutaneous infusion of apomorphine (APM‐csi) can provide a comparable improvement on motor function in patients with advanced Parkinson's disease (PD), but the mechanisms by which both therapies exert their effects are different. We analyzed the cognitive effects of APM‐csi. We also compared neuropsychological effects induced by STN‐DBS and APM‐csi in advanced PD to ascertain the neuropsychological aspects relevant in determining the therapeutic procedure that is the most appropriate in a particular patient. We studied 9 patients treated with STN‐DBS and 7 patients with APM‐csi. Neuropsychological measures included Rey's Auditory‐Verbal Learning, Stroop, Trail Making, phonetic verbal fluency, and Judgment of Line Orientation tests. In the APM‐csi group, significant changes were not observed in the neuropsychological tests performance. By contrast, in the STN‐DBS group, moderate worsening was found in phonetic verbal fluency and Stroop Naming scores that was partially reversible at long‐term follow‐up and did not have consequences on regular activities. Consequently, these findings could be interpreted as being not relevant in deciding the most suitable treatment in a given patient. © 2004 Movement Disorder Society
Inverse boundary value problem for ocean acoustics using point sources
Authors: Ikehata M. , Makrakis G. N. , Nakamura G.
Published: July 2004

We prove the uniqueness for the identification of the refraction index for an inhomogeneity of compact support in an oceanic acoustic waveguide, assuming as observation data the Green's function on the surface of a vertical cylinder surrounding the inhomogeneity. Copyright © 2004 John Wiley & Sons, Ltd.
AAA architecture for mobile IPv6 based on WLAN
Authors: Wang R. C. , Chen R. Y. , Chao Han‐Chieh
Published: July 2004

Mobility support for Internet devices is quite important for consumer electronics. The number of the hand‐held devices is growing quickly. However, there are not enough IP addresses for the number of the rapidly growing devices in the All‐IP generation. Internet Protocol version 6 (IPv6) was therefore adopted to solve these problems. Our purposed structure is based on IEEE 802.11. However, IEEE 802.11 has a serious security drawback. Further, from the Internet Service Providers' point of view, accounting is a potential problem. A mechanism combining Mobile IPv6 and AAA based on IEEE 802.11 to overcome these problems is essential.

Both Internet Protocol version 4 (IPv4) and IPv6 support IP security (IPsec) when data packets are exchanged across the IP network. IPsec operates at the IP layer. It can support system authentication and authorization, However, it lacks a system accounting function. Therefore ISPs cannot establish correct billing for their services. This is the reason why we chose to combine the wireless network and AAA functions.

In this paper, the AAA mechanism is used to protect security, with the architecture having authentication, authorization, and accounting functions. We will discuss the benefits of AAA and state the reason why we choose to combine AAA with the mobility architecture. Copyright © 2004 John Wiley & Sons, Ltd.
Autoregressive video conference models
Authors: Alheraish A.
Published: July 2004

Video conferencing is an important application that has been extensively used in IP, ATM networks, and TV broadcasting as a means of interactive communications. Teleconferencing video traffic consists of video scenes in which one or more people are talking with low to medium motion and almost unchanged background. To reflect the properties of video signals in the design of communication and transmission networks, modeling this teleconference video has received considerable attention.

For over a decade, there has been an enormous amount of interest and research in traffic modeling of compressed variable bit rate (VBR) video. An essential class of video models that has received much attention lately is regression models. This paper presents a survey of the state of the art regression traffic studies that have been proposed in the literature to model teleconference video. After an introduction to the basic definition of the regression process, the third section begins with a discussion of the earlier regression models. Then, a number of recent regression models are discussed. The paper concludes with a comparison of all the models, recommendations, and open problems. Copyright © 2004 John Wiley & Sons, Ltd.
Development of e‐government: a STOPE view
Authors: Bakry Saad Haj
Published: July 2004

The transition from conventional government services to e‐government services is becoming an international trend in various parts of the world. This transition is useful in two main ways. It provides benefits not only to the government, but also to all organizations and people, contributing to what is now known as the digital economy and the well being of the society. The transition is also an opportunity for the government to reorganize its services and reduce, or even eliminate, unnecessary overheads and inefficiencies that may exist in its traditional services. This paper uses the STOPE (Strategy / Technology / Organization / People / Environment) development profile to explore the transition to e‐government, and to support its continuous improvement. The paper identifies e‐government within the broad scope of e‐development towards the digital economy using STOPE. It describes its basic processes, and emphasizes its potential benefits. The paper also discusses maximizing these benefits using proven techniques, including TQM (Total Quality Management), BPR (Business Process Re‐engineering), and Six Sigma; in addition to experience accumulated by early e‐government adaptors. Based on STOPE, recommendations on maximizing the benefits are then introduced. Finally conclusions and potential future work are discussed. In this respect, a specific future work concerned with STOPE‐based development of typical e‐government services is proposed. The work would be useful for standardizing basic e‐government services at the national and international levels, so that well‐designed e‐government services can be globalized. Copyright © 2004 John Wiley & Sons, Ltd.
Self‐aware management of IP networks with QoS guarantees
Authors: Krief Francine
Published: July 2004

Self‐aware management allows the network to react and to adapt to changes of situation. In this paper an architecture is described for self‐aware management of IP networks offering QoS guarantees. This architecture uses policy‐based management and multi‐agent systems. The originality of the present approach lies in the intention to give a real autonomy to the components intervening in the chain of services in terms of internal decisions and configuration. Our solution allows the self‐configuration, self‐provisioning and self‐monitoring of service as well as the proactive service level agreement management. Copyright © 2004 John Wiley & Sons, Ltd.
A distributed networking system for multimedia Internet access service using ATM over ADSL
Authors: Hong Daniel Won‐Kyu , Hong Choong Seon
Published: July 2004

This paper proposes a distributed networking system architecture for Internet‐access service provision using ATM over xDSL technology. We describe the hierarchical network model in deploying ADSL services across the ATM access networks, which can easily accommodate the explosive growth of ADSL subscribers in the future. In addition, this paper describes the distributed networking system and its capability to provide a systemic network management using the principal networking concepts of service ordering, addressing, routing, adaptation and switching. All of the networking system components with CORBA objects in favor of the distribution and location transparency are defined and described using the CORBA interface description language (IDL) for commonality. Lastly, we present its implementation and operation in Korea Telecom. Copyright © 2004 John Wiley & Sons, Ltd.
An integrated simple approach for the analysis of Internet backbone networks
Authors: Bakry Saad Haj , Al‐Bassam Bassam , Alheraish Abdulmohsen
Published: July 2004

This paper presents an integrated and simple approach for the analysis of Internet backbone networks, emphasizing the need for a balance between the network resources utilization requirements of the Internet services providers (ISPs) and the services delay constraints of the Internet users (IUs). The integration of the approach is achieved by putting together the various issues associated with the target analysis, including network topology, capacity, traffic load, routing, traffic flow, and performance; and by considering the analysis both at the link level and at the path level. The simplicity of the approach is achieved by eliminating unnecessary details; and by allowing the approach to be applied in easy steps, using an open source, straightforward computer program. A typical example is used to illustrate the practical application of the approach. The work would be useful to the designers and administrators of ISP networks facing the continuous challenge of newer e‐services and higher user traffic.  Copyright © 2004 John Wiley & Sons, Ltd.
DRED‐MP: Queue management with multiple levels of drop precedence
Authors: Aweya James , Ouellette Michel , Dasylva Abel , Montuno Delfin Y.
Published: July 2004

There is current interest in differentiated service architectures where packets with different priorities can share the same queue. In the case of congestion, packets marked with higher drop probability are preferentially dropped in order to make buffer room for packets marked with lower drop probability. Active queue management (AQM) based on randomized packet dropping has become a key component of this packet forwarding model. This paper extends our previously developed AQM algorithm called DRED with multiple packet drop precedence to allow for priority treatment of traffic in a network. The main advantage of using the DRED algorithm is the lower parameter configuration complexity it offers and the ease of configuration for a wide range of network conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis, characterization, and curing kinetics of novel ladder‐like polysilsesquioxanes containing side‐chain maleimide groups
Authors: Krishnan P. Santhana Gopala , He Chaobin , Shang Christine Tay Shang
Published: July 2004

Two ladder‐like polysilsesquioxanes (LPS) containing side‐chain maleimide groups have been synthesized successfully by reacting N‐(4‐hydroxyphenyl)maleimide (HPM) with LPS containing 100 mol % of chloropropyl groups (Ladder A) and 50 mol % of each methyl and chloropropyl group (Ladder B). HPM was synthesized by reacting maleic anhydride with 4‐aminophenol, and the resulting amic acid was imidized using p‐toluenesulfonic acid as a catalyst (Scheme 1). The LPSs were characterized by Fourier transform infrared (FTIR), 1H nuclear magnetic resonance (NMR), proton‐decoupled 13C NMR, 29Si NMR, wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Characterization indicated that these polymers had ordered ladder‐like structures with possible defects. These polymers were soluble in common solvents at ambient temperature, which suggested that they were not crosslinked. Both the polymers and the HPM were cured, and their kinetics were followed by dynamic DSC. The Ozawa and Kissinger methods were used to calculate activation energies for curing. Curing increased the temperature at which both 5% weight loss and maximum rate of weight loss were observed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4036–4046, 2004
Direct measurement of structural diversity in single molecules of a chiral helical π‐conjugated polymer
Authors: Shinohara Ken‐ichi , Kitami Takeshi , Nakamae Kouichi
Published: July 2004

Using a noncontact atomic force microscope, we found that single molecules in a chiral helical π‐conjugated polymer could form a unique periodic structure having a pitch of about 20 nm on the surface of a mica substrate. The diversity of the periodic structures is also discussed. Some basic insights into the characteristics of single molecules (or their individual characteristics) in π‐conjugated polymers are revealed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3930–3935, 2004
Mechanistic aspects of ester–carbonate exchange in polycarbonate/cycloaliphatic polyester with model reactions
Authors: Jayakannan M. , Anilkumar P.
Published: July 2004

The reactive blending of bisphenol A polycarbonate (PC) with poly(1,4‐cyclohexanedimethylene‐1,4‐cyclohexanedicarboxylate) (PCCD) was investigated with a new high‐temperature solution‐blending methodology. The ester–carbonate exchange reaction (transesterification) in the blends was studied with NMR and Fourier transform infrared. The composition analysis of the PC/PCCD blends was performed with 1H NMR, and the molecular weights were determined with viscosity methods. 1,4‐Dimethylcyclohexanedicarboxylate, 1,4‐cyclohexanedicarboxylic acid, and 1,4‐cyclohexanedimethanol were reacted with PC to study the tendency of polyester chain‐end reactions such as transesterification, acidolysis, and alcoholysis. These model reactions revealed that the reactive blending was affected by both alcoholysis and transesterification, whereas acidolysis was absent. The model reaction products were used to study the mechanistic aspects of PC/PCCD reactive blending, which indicated the formation of three stable triads; two corresponded to symmetrical and unsymmetrical aromatic–cycloaliphatic esters, and the other corresponded to aromatic–cycloaliphatic ethers. The composition analysis confirmed that in PC/PCCD reactive blending, the exchange reaction predominantly occurred in the polymer main chains, and the influence of the end groups was insignificant. The effect of the catalyst concentration and PC/PCCD composition on the extent of the exchange reaction was also investigated. Thermal analysis by differential scanning calorimetry revealed that the ester–carbonate exchange enhanced the compatibilization of PC/PCCD, and a single glass‐transition temperature was observed for the miscible blends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3996–4008, 2004
What did he know, and when did he know it? Putting Glenn Trewartha's call for population geography into historical perspective
Authors: Weeks John R.
Published: July 2004

Glenn Trewartha's Presidential Address to the AAG in 1953 sought to establish population as the connective tissue between physical and human geography. In discussing the important role of population studies in the discipline, Trewartha was not a voice in the wilderness; rather he was one of a growing body of voices calling for increased understanding of the role that demographic change can play not just in the social world, but in the way in which humans interact with, use, and interpret the physical environment. It is a point still worth repeating and pushing forward, but in general the field of geography responded only by creating a subdiscipline of population geography, and we are still fighting to get out of that cul‐de‐sac and on to the main road. Copyright © 2004 John Wiley & Sons, Ltd.
The past, present and future of population geography: reflections on Glenn Trewartha's address fifty years on
Authors: Graham Elspeth
Published: July 2004

On re‐reading Trewartha's address 50 years after it was written, I am prompted to reflect on both the historical and geographical situatedness of his conception of a disciplinary space for population geography, as well as on my own concerns about population geography in the early twenty‐first century. Trewartha's case for population geography, I suggest, reveals its cultural embeddedness within American geography of that time. However, it remains of more than historical interest since a similar case has yet to be articulated by the present generation of Anglo‐American population geographers. I argue that, despite evident successes, population geography is currently facing two problems relating to its identity. The first arises from its marginalised position within human geography; and the second is associated with what might be called an ‘imbalance’ in the subject matter of research, where migration studies have become increasingly dominant. Both problems raise questions about the geographical credentials of population geography, and I ask what the future research agenda should be. New research frontiers appear to be re‐mapping the spaces of knowledge in ways that could produce new configurations of the academy. In this context, the future of population geography seems uncertain. Copyright © 2004 John Wiley & Sons, Ltd.
On the boundaries of a subfield: social theory's incorporation into population geography
Authors: Silvey Rachel
Published: July 2004

In recent years, migration research has contributed to developing the connections between population geography and social theory. Critical and feminist geographers have played a central role in bringing into dialogue the concerns of objectivist and interpretivist research on spatial mobility. This article reviews some of this recent work, and argues that the issues at the core of critical migration studies are also those animating the discipline of geography more broadly. Inasmuch as migration research is engaging population geography with social theoretical debates, it is contributing towards the achievement of Trewartha's goal of placing population research in a pivotal position within the discipline of geography. Copyright © 2004 John Wiley & Sons, Ltd.
On being part of population geography's future: population–environment relationships and inter‐science initiatives
Authors: Conway Dennis
Published: July 2004

Looking to the future, why not err on the adventurous side? Accordingly, I would like to promote two ‘geographies of population relations’, which can be framed as post‐disciplinary, inter‐science initiatives: namely, population–environment relationships, and migration–development–environment interactions and relationships. Population geographers may therefore need to reposition themselves to become involved in inter‐science research and participate with environmental, natural and physical scientists and GIS specialists in an evolving realm that is ‘post‐disciplinary’ rather than within our longstanding (and quite comfortable) subdiscipline. And, we can embark on team efforts and such post‐disciplinary projects in the firm knowledge that the global scientific community has at last recognised the central importance of population study in the pursuit of answers to how we might make today's and tomorrow's world more sustainable and healthy. Finding paths to human and environmental sustainability must be one of our academic missions, because it is public health that is under threat, not just environmental deterioration. Population–environment geographers, therefore, have common cause with medical geographers and those in the public health sphere, as well as environmental scientists, development geographers and political ecologists, among others. Population–environment–development interactions and interrelationships are an ‘inter‐science’, effort, and tomorrow's population geographers should be encouraged to join. Copyright © 2004 John Wiley & Sons, Ltd.
The post‐Trewartha boom: the rise of demographics and applied population geography
Authors: Plane David A.
Published: July 2004

This essay focuses on the rise of applied population geography coincident with the lifecourse of persons born 50 years ago when Glenn Trewartha presented ‘A case for population geography’. Applied population geography and demographics came of age along with the post–Second World War baby boom generation. At the present time and in coming decades, new sources of population data and modes of analysis should lead to an ever‐expanding role for ‘geographic method’ in population research, the business world and governmental realms. The paper concludes with some thoughts on geographical education in the face of a robust job market for students trained for careers in demographics and local scale planning. Copyright © 2004 John Wiley & Sons, Ltd.
Searching for a residential resting place: population in‐migration and circulation in Mid‐Wales
Authors: Walford Nigel
Published: July 2004

Mid‐Wales has experienced considerable fluctuation in its intercensal population change over many decades. Having undergone a protracted period of depopulation, mainly connected with industrial restructuring in various sectors and the general process of urbanisation, its population levels started to rise in the 1960s and 1970s. A significant part of this growth is attributed to a change in the direction of migration, with people moving into rather than out of the area, although analysis of aggregate movements has often obscured differential patterns at the settlement scale. Using empirical information from quantitative surveys of some 260 households and 690 individuals separated by a five‐year time interval within the area, this paper explores issues relating to people's migration history and to attitudinal differences between indigenous and outsider households. In particular it looks at the geographical range of migratory circulation within the Mid‐Wales region, and whether population changes at the community scale are connected with this circulatory process or with the arrival of people from outside. Copyright © 2004 John Wiley & Sons, Ltd.
Lowest low fertility in an urban context: the role of migration in Turin, Italy
Authors: Michielin Francesca
Published: July 2004

In countries with so‐called ‘lowest‐low’ fertility, the lowest fertility levels are seen in the cities. The main reason for this is the difference in the cost of living, combined with income constraints in cities, compared with rural areas. If we focus our attention on the centre of an urban area, migration needs to be taken into account, since migrants may have particularly low fertility levels. In this paper we use the Turin Longitudinal Study, which has data on all people who have ever been residents of Turin (Italy) during the period 1971–2001. We study the interdependencies between fertility and out‐migration choices for a selected group from the 1956 birth cohort. Our findings underline the important role of economic resources and life‐cycle events which seem to guide both fertility and migration behaviours. Moreover, while having a child significantly hampers long‐distance migration, it has less impact on short‐distance moves. Copyright © 2004 John Wiley & Sons, Ltd.
The role of metallic impurities in oxide semiconductors: first‐principles calculations and PAC experiments
Authors: Errico L. A. , Fabricius G. , Rentería M.
Published: July 2004

We report an ab‐initio comparative study of the electric‐field‐gradient tensor (EFG) and structural relaxations introduced by acceptor (Cd) and donor (Ta) impurities when they replace cations in a series of binary oxides: TiO2, SnO2, and In2O3. Calculations were performed with the Full‐Potential Linearized‐Augmented Plane Waves method that allows us to treat the electronic structure and the atomic relaxations in a fully self‐consistent way. We considered different charge states for each impurity and studied the dependence on these charge states of the electronic properties and the structural relaxations. Our results are compared with available data coming from PAC experiments and previous calculations, allowing us to obtain a new insight on the role that metal impurities play in oxide semiconductors. It is clear from our results that simple models can not describe the measured EFGs at impurities in oxides even approximately. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical conductivity of MoS2 based organic–inorganic nanocomposites
Authors: Benavente E. , Santa Ana M. A. , González G.
Published: July 2004

The electrical conductivities of a series of MoS2‐organic layer nanocomposites prepared by the intercalation of donors like poly(ethylene oxide) and secondary amines are compared. Although for intercalated MoS2 species a metallic behavior is expected, the products behave as semiconductors probably because of their layered nature. Observed conductivities at room temperature depend on the host‐guest charge transfer reflected in both the amount of residual lithium and the donor intercalation degree, as well as on the nature of the donor. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The thermal conductivity of inhomogeneous thermoelectric materials
Authors: Goldsmid H. J. , Sharp J. W.
Published: July 2004

Previous measurements on polycrystalline Bi–Sb have suggested an anomalously low value for the electronic thermal conductivity. These measurements were made using the Harman technique in which the figure of merit is found from the difference between the adiabatic and isothermal electrical resistivities. We now demonstrate that the determination of the thermal conductivity using this approach is unreliable if the material is inhomogeneous. Such inhomogeneity can be chemical in its origin or it can arise from anisotropic thermoelectric parameters in a polycrystalline sample. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytical tight‐binding calculations for optical absorption in single wall carbon nanotubes
Authors: Buonocore F. , Vinciguerra V. , Coffa S.
Published: July 2004

We present our calculations of the optical absorption for dipole direct transitions in the tight binding zone folding scheme for single wall carbon nanotubes. We have applied the Fermi's golden rule by calculating the electric dipole matrix element and we provide an analytical expression for it. We have calculated the optical absorption of semiconducting zig‐zag SWNTs equally distributed and with gaussian distribution of the diameters, where collisional broadening of the density of states was taken into account. The calculated behavior is in agreement with optical density measurements for SWNTs. Our analytical calculations will be useful for the analysis of the optical emission and absorption from single wall carbon nanotubes. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Melting volume change of different crystalline lattices
Authors: Lu H. M. , Jiang Q.
Published: July 2004

Through considering the packing density and the lattice contraction of Goldschmidt's premise, volume changes of elements crystals with different structures on melting are modeled. It is found that the predictions of the model are in agreement with the experimental and other theoretical results. In addition, the volume change of the solid–solid transition is also determined. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Estimation of infectious disease parameters from serological survey data: the impact of regular epidemics
Authors: Whitaker H. J. , Farrington C. P.
Published: July 2004

Serological surveys are a useful source of information about epidemiological parameters for infectious diseases. In particular they may be used to estimate contact rates, forces of infection, the reproduction number and the critical vaccination threshold. However, these estimation methods require the assumption that the infection is in endemic equilibrium. Such equilibria seldom exist in practice: for example, many common infections of childhood exhibit regular epidemic cycles. In this paper, we investigate whether ignoring such cycles produces biased estimates. We apply the methods to data on mumps and rubella in the U.K. prior to the introduction of the combined measles, mumps, rubella (MMR) vaccine. We conclude that past epidemics have only a marginal effect on estimates, and that standard methods that do not adjust for regular epidemics are valid. Copyright © 2004 John Wiley & Sons, Ltd.
Local influence analysis when interfacing toxicokinetic and proportional hazard models
Authors: Sartori Nicola , Thomaseth Karl , Salvan Alberto
Published: July 2004

We present a local influence analysis to assigned model quantities in the context of a dose–response analysis of cancer mortality in relation to estimated absorbed dose of dioxin. The risk estimation is performed using dioxin dose as a time‐dependent explanatory variable in a proportional hazard model. The dioxin dose is computed using a toxicokinetic model, which depends on some factors, such as assigned constants and estimated parameters. We present a local influence analysis to assess the effects on final results of minor perturbations of toxicokinetic model factors. In the present context, there is no evidence of local influence in risk estimates. It is however possible to identify which factors are more influential. Copyright © 2004 John Wiley & Sons, Ltd.
Flexible modelling of discrete failure time including time‐varying smooth effects
Authors: Tutz G. , Binder H.
Published: July 2004

Discrete survival models have been extended in several ways. More flexible models are obtained by including time‐varying coefficients and covariates which determine the hazard rate in an additive but not further specified form. In this paper, a general model is considered which comprises both types of covariate effects. An additional extension is the incorporation of smooth interaction between time and covariates. Thus, in the linear predictor smooth effects of covariates which may vary across time are allowed. It is shown how simple duration models produce artefacts which may be avoided by flexible models. For the general model which includes parametric terms, time‐varying coefficients in parametric terms and time‐varying smooth effects estimation procedures are derived which are based on the regularized expansion of smooth effects in basis functions. The approach is used to model the sojourn time in a psychiatric hospital. It is demonstrated how initial conditions which have non‐linear influence are damped over time. Copyright © 2004 John Wiley & Sons, Ltd.
Sample size for testing and estimating the difference between two paired and unpaired proportions: a ‘two‐step’ procedure combining power and the probability of obtaining a precise estimate
Authors: Cesana Bruno Mario
Published: July 2004

Clinical trials and scientific research studies are currently planned calculating sample sizes to fulfill power requirements, but the simultaneous need to obtain a satisfactorily precise effect estimate is not widely recognized. I have devised a ‘two‐step’ iterative procedure for comparing two binomial parameters for two paired and unpaired proportions (the most frequent situations in scientific research), which takes into account power and the probability of obtaining a predetermined precision of the effect estimate. The first step provides the sample size for the power of the statistical test, the expected width of its corresponding confidence interval, and the probability of obtaining, under the alternative hypothesis, confidence intervals whose width is less than that expected. The second step iteratively increases this sample size until the probability of obtaining such confidence intervals exceeds a required threshold. Copyright 2004 © John Wiley & Sons, Ltd.
Imputing gene–treatment interactions when the genotype distribution is unknown using case‐only and putative placebo analyses—a new method for the Genetics of Hypertension Associated Treatment (GenHAT) study
Authors: Davis Barry R. , Ford Charles E. , Boerwinkle Eric , Arnett Donna , Eckfeldt John , Black Henry
Published: July 2004

There is a sizeable literature on methods for detecting gene–environment interaction in the framework of case‐control studies, particularly with reference to the assumption of independence of genotype and exposure. In the context of a clinical trial, wherein gene–drug interactions with regard to outcomes are examined, these methods may be readily applied, as gene and drug are independent by randomization.

In an active‐controlled trial (experimental treatment vs standard) that has collected genotype information, gene–drug interactions can be estimated. In addition, the effect of the experimental treatment vs placebo can be imputed by using data from a historical placebo‐controlled trial (standard vs placebo) if either (a) genotype information is available from the historical trial or (b) assumptions are made about the prevalence of genotype and the odds ratios of genotype and disease in the historical trial using information from other studies. Motivation for these procedures is provided by the Genetics of Hypertension Associated Treatment, a large pharmacogenetics, ancillary study of a hypertension clinical trial, and examples from published hypertension trials will be used to illustrate the methods. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling relative survival using transformation methods
Authors: Price Dionne L. , Manatunga Amita K.
Published: July 2004

Patient survival is often assessed as a measure of effectiveness of treatment in cancer clinical trials. The relative survival rate is a measure of patient survival corrected for the effect of other causes of death. We incorporate an additive hazards model for the overall force of mortality focusing attention on the form of the underlying disease process. Transformation models for the cause‐specific hazard rate describing the disease process are considered. We demonstrate a method for estimating the transformation parameter providing insight into the appropriate choice of model structure. The models include the additive and multiplicative structures as special cases. We write the models in the generalized linear model framework and demonstrate ease of fitting via existing statistical software. The methodology is applied to a Hodgkin's disease data set to assess the effect of clinical trial results on population survival. Our analysis concludes that the multiplicative structure provides a more appropriate description of the data as compared to the additive structure. Copyright © 2004 John Wiley & Sons, Ltd.
Covariate adjustment in clinical trials with non‐ignorable missing data and non‐compliance
Authors: Levy Douglas E. , O'Malley A. James , Normand Sharon‐Lise T.
Published: July 2004

Estimating causal effects in psychiatric clinical trials is often complicated by treatment non‐compliance and missing outcomes. While new estimators have recently been proposed to address these problems, they do not allow for inclusion of continuous covariates. We propose estimators that adjust for continuous covariates in addition to non‐compliance and missing data. Using simulations, we compare mean squared errors for the new estimators with those of previously established estimators. We then illustrate our findings in a study examining the efficacy of clozapine versus haloperidol in the treatment of refractory schizophrenia. For data with continuous or binary outcomes in the presence of non‐compliance, non‐ignorable missing data, and a covariate effect, the new estimators generally performed better than the previously established estimators. In the clozapine trial, the new estimators gave point and interval estimates similar to established estimators. We recommend the new estimators as they are unbiased even when outcomes are not missing at random and they are more efficient than established estimators in the presence of covariate effects under the widest variety of circumstances. Copyright © 2004 John Wiley & Sons, Ltd.
Creating the OOSPICE model architecture—A case of reuse
Authors: Henderson‐Sellers B. , Bohling J. , Rout T.
Published: July 2004

The OOSPICE project aims at creating a capability assessment package for component‐based development (CBD), which complements and extends the ISO 15504 technical report (SPICE) and its pending standard. In addition, it will offer support for process definition, creation and tailoring in the CBD domain. The major deliverables are a process reference model for CBD, a process assessment methodology, a new CBD methodology and supporting toolset, and an underpinning CBD process metamodel. Here, we evaluate the various terminologies in current usage in OO, CBD, capability assessment and the ISO standards, and then describe the important architectural framework of the project, which brings together the two previously disparate fields of process and methodology metamodeling with capability assessment and improvement. Additionally, we show how elements of preexisting standards, such as ISO 15504 and ISO 12207, as well as elements of existing OO process metamodels can be successfully reused to create a standard for this new focus on component‐based systems development. Copyright © 2004 John Wiley & Sons, Ltd.
Discrepancy between cell injury and benzodiazepine receptor binding after transient middle cerebral artery occlusion in rats
Authors: Abe Kohji , Kashiwagi Yuto , Tokumura Miwa , Hosoi Rie , Hatazawa Jun , Inoue Osamu
Published: July 2004

We investigated postischemic alterations in benzodiazepine receptor, D1 dopamine receptor, and muscarinic acetylcholine receptor binding after transient middle cerebral artery (MCA) occlusion in rats using [3H]‐flumazenil, [3H]‐SCH23390, and [3H]‐N‐methyl‐4‐piperidyl benzilate ([3H]‐NMPB), respectively, as radioligand. These ligand bindings were determined at 3 and 24 h and at 3 and 7 days after ischemia/reperfusion of MCA by using autoradiographic methods. Ischemic cell injury was clearly detected from 3 h after ischemia/reperfusion and progressively increased from 3–24 h after ischemia/reperfusion of MCA. The area of cell injury reached maximum at 24 h after ischemia/reperfusion of MCA. [3H]‐SCH23390 binding was reduced to 47% of the contralateral side at 3 days after ischemia/reperfusion of MCA. After 7 days, [3H]‐SCH23390 binding was further reduced by 20% in the striatum. [3H]‐NMPB binding was slightly decreased in both the striatum and cerebral cortex at 3 days after ischemia/reperfusion of MCA, and [3H]‐NMPB binding in the striatum and cerebral cortex were reduced to 42 and 62% of the contralateral side at 7 days after ischemia/reperfusion of MCA. [3H]‐NMPB was also decreased at 24 h. In contrast, [3H]‐flumazenil binding was not decreased in the striatum and cerebral cortex within 7 days after ischemia/reperfusion of MCA. These results suggest that [3H]‐SCH23390 and [3H]‐NMPB binding do not correlate with cell injury by ischemia/reperfusion, although vulnerability to ischemia/reperfusion was observed with these receptors. In addition, central benzodiazepine receptor imaging might be essentially stable to neuronal cell injury induced by transient focal cerebral ischemia in rats, in contrast to the results of PET studies. Synapse 53:234–239, 2004. © 2004 Wiley‐Liss, Inc.
Determination of bladder neck position by intraoperative introital ultrasound in colposuspension: outcome at 6‐month follow‐up
Authors: Viereck V. , Bader W. , Skala C. , Gauruder‐Burmester A. , Emons G. , Hilgers R. , Krauss T.
Published: July 2004

Objective

To determine whether open colposuspension modified by intraoperative ultrasound to prevent overcorrection is a safe and effective procedure.

Methods

Ninety women operated on for urodynamically proven genuine stress urinary incontinence underwent intraoperative introital ultrasound in a prospective observational clinical study. The positions of the bladder neck and proximal urethra were assessed by determining the parameters height (H), distance (D) and the urethrovesical angle (β) perioperatively and for up to 6 months postoperatively. Colposuspension of the bladder neck was performed with a vertical height correction, ΔH (resting Hintraop − resting Hpreop) of 1 to 10 mm. Bladder neck positions were determined on an individual basis by introital ultrasound before, during and after surgery.

Results

Surgical elevation of the bladder neck (median height correction, ΔH 4 mm) resulted in a median intraoperative elevation of 9 mm (6 months: 8 mm). All postoperative measurements showed a significant reduction of the median linear movement of the bladder neck during straining (P < 0.0001). Anti‐incontinence surgery resulted in a significant reduction of funneling and hypermobility 6 months after surgery (P < 0.0001). At 6‐month follow‐up, 94% (85/90) of the women were continent. Evaluation immediately after surgery showed voiding difficulties and urge symptoms in 9% (8/90) of the patients each and de novo urge incontinence in 1% (1/90).

Conclusions

Intraoperative introital ultrasound can help to optimize the colposuspension procedure. Ultrasonographic measurement of height H allows for objectively assessing the surgical procedure and can reduce postoperative complications by preventing excessive correction. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Can Early Diagnosis of Symptomatic Colorectal Cancer Improve the Prognosis?
Authors: Gonzalez‐Hermoso Fernando , Perez‐Palma Julian , Marchena‐Gomez Joaquin , Lorenzo‐Rocha Nieves , Medina‐Arana Vincente
Published: July 2004

Patients with colorectal cancer continue to present with relatively advanced tumors. Delay in diagnosis is often believed to have been a contributing factor, and the validity of this hypothesis has seldom been questioned. The aim of this study was to establish whether a delay in diagnosis is related to long‐term survival and if the most frequent symptoms were related to the stage or time at which the carcinoma was diagnosed. Data from 660 patients surgically treated for uncomplicated colorectal carcinoma in our institution between 1985 and 2000 were analyzed retrospectively. Age, sex, initial symptoms, duration of symptoms, neoplasm location, curative surgery, TNM stage, and survival time were the variables recorded. Patients were classified into two groups according to symptom duration: < 3 months versus ≥ 3 months. Comparative statistical analysis was performed for the two groups as well as the initial symptom, TNM stage, and survival time. Also, the initial symptoms most frequently reported were compared with the TNM stage. The two groups were found to be equal with regard to distribution of age, gender, location of the neoplasm, type of surgery performed, and TNM stage. We found that symptom duration was shortened in the presence of abdominal pain (p = 0.002) [odds ratio (OR) 0.53; 95% confidence interval (CI) 0.35–0.80] and was delayed in the presence of an anemic syndrome (p = 0.006) (OR 2.4; 95% CI 1.27–4.56). Also, the stage of the neoplasm was related to rectal bleeding (p < 0.001) and abdominal pain (p = 0.008). The log‐rank test indicated that duration of symptoms was not related to long‐term survival (p = 0.90). We concluded that the duration of colorectal cancer symptoms is not related to the stage or prognosis of tumors.
Regression of Type II Gastric Carcinoids in Multiple Endocrine Neoplasia Type 1 Patients with Zollinger‐Ellison Syndrome after Surgical Excision of All Gastrinomas
Authors: Richards Melanie L. , Gauger Paul , Thompson Norman W. , Giordano Thomas J.
Published: July 2004

Enterochromaffin‐like (ECL) tumors are documented in patients with hypergastrinemia secondary to chronic atrophic gastritis or with Zollinger‐Ellison syndrome and multiple endocrine neoplasia type 1 (ZES‐MEN‐1). In patients with ECL tumors and atrophic gastritis, normogastrinemia after antrectomy has resulted in resolution, regression, or stabilization of ECL tumors. The natural history of ECL tumors associated with ZES‐MEN‐1 following normalization of gastrin levels after gastrinoma resection has not been previously reported. The purpose of this study was to determine the course of ECL tumors in patients with ZES‐MEN‐1 following normalization of serum gastrin levels after gastrinoma resection. Two patients with ZES‐MEN‐1 had biopsy‐proven ECL tumors on endoscopic evaluation. They then underwent surgical exploration that included distal pancreatectomy, enucleation of pancreatic head tumors, duodenotomy with excision of submucosal tumors, and peripancreatic lymphadenectomy. Gastric ECL tumors larger than 1.0 cm were locally excised. Patients underwent long‐term follow‐up with biochemical and endoscopic surveillance. Normogastrinemia was achieved and sustained following gastrinoma resection in two patients with ZES‐MEN‐1. Periodic endoscopic surveillance over a 6‐year period showed complete resolution of the ECL tumors. The development of ECL tumors associated with ZES‐MEN‐1 is multifactorial. Studies identified a genetic influence on tumor growth with loss of heterozygosity at the MEN‐1 gene locus in ECL tumors. The resolution of ECL tumors in ZES‐MEN‐1 patients who are normogastrinemic indicates that an elevated gastrin level is a primary initiator for development of these tumors. Therefore both genetic defects and hypergastrinemia are causative agents. Normalization of serum gastrin levels is critical for the prevention of aggressive forms of ECL tumors.
The processes of iron deposition in the common hornet (vespa affinis)
Authors: Hsu Chin‐Yuan
Published: July 2004

Summry— Among insects, only honeybees and bumblebees deposit iron biominerals intracellularly. Although hornet's behaviour is affected by the magnetic field and their abdomen has magnetic remanence, it is not known whether hornets (Vespa affinis) deposit iron biominerals and whether the process of iron deposition in hornets is the same as that of honeybees and bumblebees. Transmission electron microscopy and atomic emission spectroscopy were employed to study intracellular iron deposition in hornets. Iron deposition began on day 2 after eclosion. Primary iron‐granules (IGs) are first formed in primary iron deposition vesicles (IDVs) by the aggregation of tiny dense particles. Primary IDVs are double membrane vesicles that seem to derive from endoplasmic reticulum (ER). Primary IGs enlarged continuously into IGs by the aggregation of tiny dense particles till day 5 after eclosion. Next, IGs and IDVs fused to enlarge on day 7. Between days 10 and 17 IGs enlarged continuously in size by the aggregation of tiny dense particles. The cloudy area beneath the inner membrane of IDVs plays an important role in the formation of the tiny dense particles. IGs became mature on day 25 and left a small space, about 10nm in width, between IGs and the outer membrane of IDVs. IDVs including IGs are randomly distributed within the cytoplasm of trophocytes beneath the cuticle of hornets. Elemental composition analysis indicates that IGs are mainly comprised of iron, phosphorus and minor amounts of calcium.
Two cAMP receptor proteins with different biochemical properties in the filamentous cyanobacterium Anabaena sp. PCC 7120
Authors: Suzuki Takayuki , Yoshimura Hidehisa , Hisabori Toru , Ohmori Masayuki
Published: July 2004

Two open reading frames (ORFs), alr0295 and alr2325, are found to encode putative cAMP receptor proteins (CRPs) in the genome of the filamentous cyanobacterium Anabaena sp. PCC 7120. These ORFs were named cAMP receptor protein‐like gene A in Anabaena sp. PCC 7120 (ancrpA) and cAMP receptor protein‐like gene B in Anabaena sp. PCC 7120 (ancrpB), respectively, and those translated products were investigated. The equilibrium dialysis measurements revealed that AnCrpA bound with cAMP specifically, while AnCrpB bound with both cAMP and cGMP, though the affinity for cGMP was weak. The binding affinity for cAMP of AnCrpA showed the lowest dissociation constant, approximately 0.8 μM, among bacterial CRPs. A gel mobility shift assay elucidated that AnCrpA and AnCrpB formed a complex with the consensus DNA sequence in the presence of cAMP, although AnCrpB did not have ordinary DNA‐binding motifs.