bluuebunny/crossref_metadata_2025_split huggingface dataset:
Provision of quality of service in wireless fourth generation networks
Authors: Zarai Faouzi , Boudriga Noureddine 
Published: December 2006

AbstractA key word describing next generation wireless networks is ‘seamless’. Wireless fourth generation (4G) networks represent a set of new technologies that will enable seamless integration of various wireless access systems, while targeting to support various sophisticated and quality of service constraining applications, such as high‐speed data services and multimedia services. This paper first proposes an architecture for 4G networks. The most significant feature of this architecture is its flexibility, openness and ability to enable seamless handoff in a single logical overlay network composed of many heterogeneous access networks. A medium access control (MAC) protocol for basic access networks is then introduced. A generic scheduling scheme, named CS‐EDF (channel state‐earliest deadline first) and the details of an efficient handoff management method are also briefly introduced. The bandwidth utilization, handoff resources reservation, and scheduling scheme performances of the proposed schemes are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Cover Picture: Investigating Direct Alkynylation at the Bridgehead of Bicyclic Cages Using Silver(I) Acetylides (Eur. J. Org. Chem. 2/2007)
Authors: Pouwer Rebecca H. , Harper Jason B. , Vyakaranam Kamesh , Michl Josef , Williams Craig M. , Jessen Carsten H. , Bernhardt Paul V. 
Published: December 2006

AbstractThe cover picture shows a rare, 80% silver, round Australian 50‐cent piece, which was introduced in 1966 when Australia changed currency from the Australian pound to the Australian dollar. It was later replaced with a copper/nickel dodecagonal (12‐sided) version in 1969. The coin underpins the reaction of a silver(I) acetylide with adamantyl iodide affording the bridgehead‐substituted adamantylacetylene. This new methodology has nanotechnological ramifications as discussed in the article by C. M. Williams et al. on p. 241 ff. Brett D. Schwartz is acknowledged for preparing the artwork for the cover picture.
Layer‐by‐Layer Assemblies of Montmorillonite and Bacterial Cytochromes for Bioelectrocatalytic Devices
Authors: Lojou E. , Bianco P. 
Published: December 2006

AbstractClay‐based layer‐by‐layer architectures are studied in view of the development of new electrode materials for two highly attractive enzymatic reactions: metal bioremediation and hydrogen uptake. The buildup of layer‐by‐layer (LBL) assemblies of positively charged specific mediators of these enzymatic reactions and negatively charged montmorillonite nanoparticles were carried out onto gold and graphite electrodes. The structure and stability of the assemblies were examined using quartz crystal microgravimetry (QCM) and electrochemical techniques. Satisfactory catalytic efficiencies were observed through the LBL construction, either for bacterial cytochrome c3‐mediated metal reduction, or hydrogen uptake via immobilized hydrogenase in the presence of an artificial shuttle, methylviologen. Interestingly, it is established that intercalating cytochrome c3 layers between hydrogenase/montmorillonite layers not only protects hydrogenase from leaching, but allows H2 uptake/evolution catalytic reaction without any additional diffusing redox mediator.
Electrostatic Assembly of a Redox Catalysis System for Detection of Glutamate
Authors: Harper Alice C. , Anderson Mark R. 
Published: December 2006

AbstractInterfacial assemblies capable of determining glutamate by redox catalysis are prepared by electrostatic assembly of alternating layers of ferrocene poly(allylamine) polymer and glutamate oxidase on a gold electrode. Deposition of the polymer was confirmed in cyclic voltammetry measurements by the presence of a surface wave corresponding to the oxidation of the ferrocene group. In the presence of glutamate in the adjacent electrolyte solution, the current increases and approaches a pseudosteady state, consistent with redox catalysis. Electrodes modified with glutamate oxidase had a linear response to glutamate up to 0.0045 M with sensitivity of 20 μA/cm2 and a limit of detection of 31.4 μM glutamate. An apparent Michaelis–Menten constant of 0.40(±0.13) mM for the confined glutamate oxidase was determined for this assembly. When used in flow‐injection experiments, glucose oxidase modified electrodes responded to transient zones of glucose; however, the detection limits of the assemblies to the flowing stream were substantially higher than found for measurements on static solutions.
Components from Sri Lankan Piper betle L. leaf oil and their analogues showing toxicity against the housefly, Musca domestica
Authors: Mohottalage Susantha , Tabacchi Raffaele , Guerin Patrick M. 
Published: December 2006

AbstractThe essential oil extracted from Piper betle L. leaf using pilot plant steam distillation was tested against the adult housefly, Musca domestica, for insecticidal activity. LC50 values at the end of 24 and 48 h exposure periods were 10.3 and 8.7 mg/dm3, respectively. Ceylon citronella oil (Cymbopogon nardus) used as a standard showed LC50s of 26.5 and 24.2 mg/dm3 for the same exposure periods. Bioassay‐guided fractionation of P. betle leaf oil revealed safrole and eugenol as the active principles against M. domestica, safrole showing LC50 values of 4.8 and 4.7 mg/dm3, and eugenol 7.3 and 6.2 mg/dm3 for the 24 and 48 h exposure periods, respectively, while citronellal (synthetic standard) showed equal LC50 values of 14.3 mg/dm3 for the same exposure periods. Using safrole as the starting compound, eight analogues were prepared to study structure–activity relationships. Among the eight analogues, dihydrosafrole gave almost equal mortality at LC50 4.7 mg/dm3 as that of the parent compound safrole after 24 and 48 h exposure, but isosafrole was twice as active as safrole, showing LC50 values of 2.3 and 2.2 mg/dm3 for the 24 and 48 h exposure periods. Our GC–MS studies on Sri Lankan P. betle leaf oil show that it contains safrole (52.7%), allylpyrocatechol diacetate (15.4%), eugenol (6.4%) and eugenyl acetate (5.8%) as the major components. Here we also present the GC–MS profile of fractions of Sri Lankan P. betle leaf oil. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical and comparative study of the agility of planar transmission lines printed on a ferroelectric thin film
Authors: Moussavou A.‐G. , Bouquet V. , Sauleau R. , Perrin A. , Guilloux‐Viry M. , Mahdjoubi K. 
Published: December 2006

AbstractIn this article, we report on simulation results at 10 GHz of planar transmission lines printed on a ferroelectric thin film deposited on sapphire and lanthanum aluminate substrates. The ferroelectric film permittivity is supposed to vary from 700 to 500. First, the main properties of microstrip (MS), coplanar waveguide (CPW) and coplanar strips (CS) namely their effective permittivity, characteristic impedance, and insertion loss are computed as a function of the physical and electrical parameters. Then their tunability and figure of merit are defined and compared. CPW and CS lines present a tunability (Δϵeff/ϵeff_max) of about 16% for a gap value g = 30 μm. The MS lines show a much less tenability of 2%. Moreover, the figure of merit of CPW and CS configurations are of 6.3 and 12.2%/dB for a gap value of 30 μm, respectively. By increasing the gap, these figures of merit can be improved up to the limiting values of 8.7% and 15.4%/dB, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 280–285, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22106
High resolution ultrawideband wall penetrating radar
Authors: Engin Erman , Çiftçioğlu Berkehan , Özcan Meriç , Tekin İbrahim 
Published: December 2006

AbstractA high resolution ultra wideband radar prototype is developed for various applications through the wall imaging. The frequency range of operation of the radar is selected to be 1.85–6 GHz in order to have high spatial resolution. Besides the hardware, we have also developed a custom image processing software which attacks the problem of false target recognition and rejection. In this article, we present our prototype along with various experimental results such as detecting stationary targets and detecting respiratory activity of a human behind a 23 cm thick brick wall. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 320–325, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22112
Propagation characteristics of complementary split‐ring resonator for wide bandgap enhancement in microstrip bandpass filter
Authors: Wu Hung‐Wei , Weng Min‐Hang , Su Yan‐Kuin , Yang Ru‐Yuan , Hung Cheng‐Yuan 
Published: December 2006

AbstractThis investigation discusses the propagation characteristics of single complementary split‐ring resonator (CSRR) in planar transmission media. To characterize the single CSRR, the effective electromagnetic parameters, such as highly frequency dependence of normalized attenuation constant (α(f)/k0), normalized phase constant (dispersion relation) β(f)/k0, and characteristic impedance (Z0(f)) are extracted with the full wave electromagnetic (EM) simulation and measurement. Additionally, the wide bandgap characteristics of periodic CSRRs are also discussed. Finally, we applied the periodic CSRRs to suppress the harmonics of the conventional dual‐mode ring bandpass filter (BPF) by using the propagation characteristics of the periodic CSRRs. The experimental results agree well with the simulated results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 292–295, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22121
New 0.18‐μm CMOS pulse generator for impulse radio ultra‐wideband communication systems
Authors: Tzou Tung‐Yuan , Chen Fu‐Chiarng 
Published: December 2006

AbstractThis article presents a new circuit to generate a higher‐order derivative Gaussian pulse for the impulse radio ultra‐wideband (IR‐UWB) communication systems. This IR‐UWB pulse generator is designed and measured with the TSMC 0.18‐μm CMOS process. The circuit is able to generate a symmetrical and low‐ringing pulse in a frequency band from 3.1 to 10.6 GHz. Our work shows that the pulse generator's output pulse width is 500 ps with an amplitude of 40 mV (peak to peak). The measurement results validate our design and the circuit functionality. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 342–345, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22132
Ultrawideband monocycle pulse generator with dual resistive loaded shunt stubs
Authors: Ma Tzyh‐Ghuang , Wu Chin‐Jay , Cheng Po‐Kai , Chou Chin‐Feng 
Published: December 2006

AbstractAn ultrawideband (UWB) monocycle pulse generator with dual resistive loaded shunt stubs is present in this article. The proposed pulse generator consists of a step recovery diode (SRD), a Schottky diode, a pair of resistive loaded stubs, and a pair of short‐circuited stubs. By introducing an additional resistive loaded stub between the SRD and the Schottky diode, the ringing tail of the impulse waveform can be substantially suppressed and the resultant monocycle pulse is well‐behaved with very low ringing level. The measurement result demonstrates a monocycle pulse with peak‐to‐peak amplitude of 550 mV, pulsewidth of 320 ps, ringing level of as low as −22 dB, and good pulse symmetry. This pulse generator is suitable for various UWB applications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 459–462, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22145
Dielectric resonator antenna: Operation of the magnetodielectric composites Cr0.75Fe1.25O3(CRFO)/Fe0.5Cu0.75Ti0.75O3(FCTO)
Authors: Rocha H. H. B. , Freire F. N. A. , Costa R. C. S. , Sohn R. S. T. M. , Orjubin G. , Junqueira C. , Cordaro T. , Sombra A. S. B. 
Published: December 2006

AbstractThe probe‐feed cylindrical dielectric resonator antennas (DRA) based on a new magnetodielectric composites Cr0.75Fe1.25O3(CRFO)/Fe0.5Cu0.75Ti0.75O3(FCTO) are investigated. The experimental and theoretical characteristics of the antenna like return loss, bandwidth, input impedance, and radiation patterns are in good agreement. Numerical validation is done, tacking into account the air gaps between the dielectric resonator and the metallic conductors. Frequency response bandwidth in the range of 6.6–11.8% was obtained for frequency operation around 4 GHz. The CRFO‐FCTO present a dielectric constant in the range of 8–13 with loss around 10−3. To summarize, the performance of a cylindrical DRA based in a new matrix CRFO/FCTO was examined. These measurements confirm the potential use of such materials for small DRA. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 409–413, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22160
Microwave holography measurement and adjustment of 25‐m radio telescope of Shanghai
Authors: Yu Hong 
Published: December 2006

AbstractIn an attempt to measure and correct the surface profile of the Sheshan 25‐m radio telescope, the author carried out a phase coherent holographic experiment at 12.26 GHz with a geostationary communication satellite SINO‐1 in the far field. To improve the spatial resolution, the author took the drift of the communication satellite into consideration. For the backend, a digital cross correlator was used to measure the complex beam pattern of the antenna under test. According to the data collected in the experiments, the holography software can give the energy distribution map, error map, and a suggested adjustment for every junction of the panels, after four iterations of measurement and adjustment in a week, the surface accuracy of the antenna is improved from 0.948 mm to better than 0.5 mm. The experiment shows that the microwave holography is much faster and more convenient than traditional method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 467–470, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22171
QSPR ofn‐Octanol/Water Partition Coefficient of Nonionic Organic Compounds Using Extended Topochemical Atom (ETA) Indices
Authors: Roy Kunal , Sanyal Indrani , Ghosh Gopinath 
Published: December 2006

AbstractConsideringn‐octanol/water partition coefficient as an important chemical property in modeling the fate and persistence of chemicals, recently introduced Extended Topochemical Atom (ETA) indices have been used to modeln‐octanol/water partition coefficient data of 122 nonionic organic compounds which are highly persistent in the environment and reported to bioconcentrate considerably in lipid tissues. In deriving the models, principal component Factor Analysis (FA) followed by Multiple Linear Regression (MLR), stepwise regression, Partial Least Squares (PLS), and Principal Component Regression Analyses (PCRA) were applied as the statistical tools. The model development process was repeated with non‐ETA (topological and physicochemical) descriptors and a combination set comprising both the ETA and non‐ETA descriptors. The models with ETA indices suggested negative contributions of groups capable of hydrogen bonding and/or polar interactions and positive contributions of volume and degree of halogen substitution to the partition coefficient. Finally, we discuss validation of QSPR models by dividing the dataset into training and test sets based on different strategies,e.g., random division, sorted log Kowdata andK‐means clusters for the factor scores of the original variable (ETA) matrix without the response property values. The ETA (FA‐MLR and stepwise regression) models were also applied on a purely external dataset (n=35) and acceptable predictiver2values (0.582 and 0.651 respectively) were obtained. The results suggest that ETA parameters are sufficiently rich in chemical information to encode the structural features contributing to then‐octanol/water partition coefficient of nonionic organic compounds and thus these merit further assessment to explore their potential in QSAR/QSPR/QSTR modeling.
Design and stability analysis of cooperative receding‐horizon control of linear discrete‐time agents
Authors: Franco Elisa , Parisini Thomas , Polycarpou Marios M. 
Published: December 2006

AbstractThis paper considers the problem of designing cooperative control algorithms for a team of distributed agents operating towards achieving a global performance objective. Each agent is assumed to evolve according to certain discrete‐time, linear dynamics and to exchange delayed state information with a subset of neighbouring or cooperating agents. The control design formulation is based on the definition of a finite‐horizon cost function that includes both the regulation and cooperation objectives. The cooperative control problem is formulated in a receding‐horizon framework, where the control law can be explicitly broken up in two components: one due to feedback from the local state variables and the other based on delayed information gathered from cooperating neighbouring agents. The stability and performance analysis of the overall system is carried out and simulation results are used to illustrate the effectiveness of the proposed control scheme. Copyright © 2006 John Wiley & Sons, Ltd.
Relative risk and acceleration in lung cancer
Authors: Berry Geoffrey 
Published: December 2006

AbstractFor a substance that increases the relative risk of disease, it does not necessarily follow that the proportion of cases due to exposure to the substance is the same as the attributable fraction in the exposed. An alternative explanation is that the substance has accelerated the occurrence of disease and, therefore, played a role in all cases. When the incidence of disease with time follows the Weibull distribution, it is well known that the proportional hazards model and the accelerated failure time model are equivalent. The purpose of this paper is to provide a numerical illustration of the relationship between the relative risk and the acceleration time of occurrence of cases. A Weibull distribution is a good approximation for lung cancer death rates up to the age of 80 years. The numerical relationship between the relative risk and the time by which cases are accelerated is given for lung cancer deaths occurring at ages of 40–75 years with relative risks of 1.01–3. As an example, for a death due to lung cancer at age 60 years in a smoker, relative risks of 2 and 1.1 due to occupational exposure to a substance correspond to accelerations of 5.2 years and 8 months, respectively. Copyright © 2006 John Wiley & Sons, Ltd.
Learning from students, inquiry into practice, and participation in professional communities: Beginning teachers' uneven progress toward equitable science teaching
Authors: Bianchini Julie A. , Cavazos Lynnette M. 
Published: December 2006

AbstractIn this research project, we investigated two beginning secondary science teachers' efforts to learn to teach science in ways that build from and celebrate the ethnic, gender, linguistic, and academic diversity of their students. To do so, we followed Troy and Brian from their preservice teacher education experiences through their first year of teaching 8th grade physical science at local junior high schools. We also conducted a follow‐up observation and interview with each participant after he had moved past the beginning stage of survival in the teaching profession—once in his fourth year of public school science teaching. Through qualitative analysis of interviews, classroom observations, and teachers' written work, we identified patterns and explored commonalities and differences in Troy and Brian's views and practices tied to equity over time. In particular, we examined successes and challenges they encountered in learning to teach science for all (a) from their students, (b) from inquiry into practice, and (c) from participation in professional communities. In our implications, we suggest ways teacher educators and induction professionals can better support beginning teachers in learning to teach science to all students. In particular, we highlight the central roles both individual colleagues and collective school cultures play in aiding or impeding beginning teachers' efforts to learn from students, from practice, and from professional communities. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 586–612, 2007.
Nuss Procedure: Pediatric Surgical Solution for Adults with Pectus Excavatum
Authors: Aronson Daniel C. , Bosgraaf Remko P. , van der Horst Chantal , Ekkelkamp Seine 
Published: December 2006

AbstractIntroductionThe aim of the study was to compare results of the Nuss procedure in adults and children.MethodsThe data were collected prospectively. Antibiotic prophylaxis was used in all patients. Differences were tested statistically.ResultsA total of 35 adults (28 men; male/female ratio 4:1) with a median age of 23 years (range 18 years to 47 years 1 month) were included in the study. A previous Welch operation had been performed in one (3%). The median operating time was 65 minutes (range 45–105 minutes). Two bars were inserted in one patient, and stabilizers were used in all. Pneumothorax occurred in 9 (26%), wound abscess in 3 (9%), and bar slips in 5 (14%). The median hospital stay was 7 days (range 4–10 days). Bars were removed in 14 (40%) patients without complications. Follow‐up occurred 6 and 12 months after bar removed, at which times no recurrence of the pectus and no sternal protrusions were seen. In the other part of the study, 141 children and adolescents (105 boys; male/female ratio 3:1) with a median age of 13 years (range 4 years 11 months to 17 years 8 months) were included. A previous Welch operation had been performed in five (4%). Two bars were inserted in four, and stabilizers were used in 100 (71%). The median operating time was 65 minutes (40–185 minutes). Pneumothorax occurred in 33 (24%), wound abscess in 1 (0.7%), and bar slips in 18 (13%). The median hospital stay was 7 days (range 5–18 days). Bars were removed in 77 (55%) without complications. Follow‐up occurred 6 and 12 months after bar removed, and the last follow‐up was eventually planned at the end of growth (age 18). The pectus recurred in one patient with Marfan syndrome, and sternal protrusion occurred in one. Differences between groups were as follows: a significantly higher proportion of adult patients were treated with stabilizers (P < 0.001), and there were significantly more wound abscesses in adults (P < 0.001).ConclusionsThe Nuss procedure is as effective for correcting pectus excavatum in adults as it is in children. However, in adults the bars tended to be less stable, and wound abscesses occurred more frequently.
Economic incentives, social norms, and the crisis of fisheries
Authors: Jackson Jeremy B. C. 
Published: December 2006

AbstractThis year's Kyoto prize signals the long overdue recognition of the fundamental interdependence of economic and ecologic systems for the protection and maintenance of ecosystem services and human well‐being. Levin (2006) and Vincent (2007) point to several of the more important ways that interdisciplinary approaches will be essential to the better quantification and understanding of the economic contributions of ecosystem services, but they differ fundamentally in their relative faith in the evolution of new social norms versus economic incentives backed up by sanctions to achieve the necessary cooperation for environmental protection. In the case of marine fisheries, social norms have proven highly effective on small spatial scales but have not taken root in the face of increasingly global markets and free trade.