bluuebunny/crossref_metadata_2025 huggingface dataset:
Faseroptisches Messsystem für räumlich verteilte Dehnungs- und Temperaturmessungen (Fiber Optic Measurement System for Spatially Distributed Strain and Temperature Measurements)
Authors: Zeh Thomas , Meixner Andreas , Koch Alexander W. , Neumann Christian
Published: December 2003

Die Verfügbarkeit dämpfungsarmer, dotierter optischer Fasern leitete im vergangenen Jahrzehnt nicht nur eine neue Epoche auf dem Gebiet der Kommunikationstechnik ein, sie eröffnete auch völlig neue Sensorkonzepte und Messsysteme. Großes Potenzial wird dabei einem Fasersensor zugesprochen, der auf in dotierte Quarzglas-Lichtwellenleiter eingeschriebenen, intrinsischen Brechzahlgittern (faseroptisches Bragg-Gitter) beruht. Diese Gitter erfassen als wellenlängenselektive Sensorelemente ortsaufgelöst u. a. Temperatur und mechanische Dehnung. Es wird ein Messsystem vorgestellt, mit welchem wellenlängenmultiplexiert eine Vielzahl von Bragg-Gittern eines Faserstrangs ausgewertet werden. Die optischen Sensorsignale werden mithilfe eines Spektrometers mit Zeilen-Detektor aufgenommen. Da am Markt schnelle Zeilen-Detektoren (Photodiodenarrays, CCD-Detektoren) verfügbar sind, begrenzt u. a. die Geschwindigkeit der digitalen Signalverarbeitung die Bandbreite eines Sensorsystems. Orientiert an den Echtzeitanforderungen entstand eine parallelisierte Signalverarbeitungsplattform mit digitalen Signalprozessoren (DSPs) und einer Gesamtverarbeitungsleistung von 2,7 GFLOPs (Giga-Floating-Point Operations Per Second) bei einer Taktrate von 150 MHz pro DSP. Diese Verarbeitungsleistung ermöglicht die Ausführung von Subpixel-Approximationsalgorithmen und die Analyse komplexer, dynamischer Dehnungsschwingungen bis zu 1 kHz an 36 Messstellen.
Neuartiger überlastfester piezoresistiver Silizium-Hochdrucksensor (A Novel Overload Resistant Piezoresistive Silicon High Pressure Sensor)
Authors: Stavroulis Stefanos , Werthschützky Roland
Published: December 2003

Bei den gegenwärtig bekannten piezoresistiven Silizium-Drucksensoren wird der zu messende Druck durch eine festeingespannte Siliziumdruckmessplatte in eine elastische Deformation umgewandelt. Aufgrund der entstehenden mechanischen Spannungen im Material ändern sich die Widerstandswerte der in der Druckmessplatte dotierten Halbleiterwiderstände. Die durch nasschemisches Ätzen hergestellte Druckmessplatte weist einen begrenzten Überlastwert auf, sodass die bekannten Silizium-Drucksensoren mit Verformungskörper zur Messung von Drücken bis maximal 1000 bar eingesetzt werden können. Bei der neuartigen Lösung besteht das Messelement aus einem unabgedünnten Siliziumchip mit piezoresistiven Widerständen auf der Oberfläche und ganzflächiger anodisch gebondeter Verbindung der Chip-Unterseite mit einem Borosilikatglas-Substrat (z.B. Pyrex). Aufgrund der Unterschiede der Elastizitätsmodule von Silizium und Pyrex treten bei allseitiger Druckeinleitung mechanische Spannungen in der Verbindungsfläche zwischen den beiden Werkstoffen auf. Die mechanischen Spannungen im Siliziumchip führen aufgrund des piezoresistiven Effekts zu einer Änderung der in seine Oberfläche implantierten Widerstände.
Modellgestütztes Mess- und Automatisierungssystem zur bedarfsgerechten Heizung und Lüftung (Model-based Automation System for Demand-based Heating and Ventilation)
Authors: Spasokukotskiy Konstantyn , Horn Michael , Tränkler Hans-Rolf
Published: December 2003

Durch Verbesserung der Heizungs- und Lüftungsstrategien im privaten Lebensbereich kann sowohl Heizenergie eingespart und damit die CO2-Emission verringert, als auch die Raumbehaglichkeit verbessert werden. Der Beitrag behandelt ein modellgestütztes Mess- und Automatisierungssystem, mit dem die Realisierung der verbesserten Strategien unter gegebenen technischen Randbedingungen praktisch erst möglich wird.
Dreiachsiger Beschleunigungssensor in Oberflächenmikromechanik (Surface Micromachined Triaxial Accelerometer)
Authors: Reichenbach Ralf , Schubert Dietrich , Gerlach Gerald
Published: December 2003

Prototypen eines oberflächenmikromechanischen dreiachsigen Beschleunigungssensors mit kapazitiver Auswertung nach dem Ausschlagverfahren wurden entworfen und realisiert. Das Funktionsprinzip wird dargestellt und mit vorhandenen Lösungen verglichen. Entwurf, Modellbildung, Herstellungsverfahren und erste Messergebnisse werden erörtert.
Winkelmessung mit planaren kapazitiven Sensoren (Angular Measurement with Planar Capacitive Sensors)
Authors: Zangl Hubert , Brasseur Georg
Published: December 2003

Neben magnetischen und optischen Methoden zur kontaktlosen Winkelmessung haben sich in letzter Zeit kapazitive Sensoren als robuste Alternative für industrielle und Automobil-Applikationen etabliert. Diese Sensoren erreichen Genauigkeiten von 0,1° und besser bei möglichen Messraten von über 10 kHz. Die heute gängigen Arten von kapazitiven Sensoren für diese Anwendungen verwenden getrennte Sende- und Empfangsplatinen, was in vielen Fällen aufgrund von erschwerter Montage und zusätzlichem Platzbedarf (und zusätzlichen Kosten) unerwünscht ist. Ebenso befindet sich die Auswerteelektronik bei diesen Sensoren in unmittelbarer Nähe zu den Elektroden, weshalb sich diese Sensoren nicht für besonders raues Umfeld eignen. Das in dieser Arbeit beschriebene Verfahren verwendet eine gemeinsame Platine für Sender und Empfänger, wobei die Auswerteelektronik bis zu einem gewissen Grad räumlich von den Elektroden getrennt sein kann. Dadurch können im eigentlichen Sensorraum hohe Temperaturen und Drücke vorherrschen, ohne dass der Sensor dadurch beeinträchtigt würde.
Mikrotaster für Anwendungen in der taktilen Wegmesstechnik (Micro Probe for Dimensional Metrology)
Authors: Bütefisch Sebastian , Solzbacher Florian , Ziermann René , Krause Peter , Büttgenbach Stephanus , Wilke Ralph , Cao S. , Pornnoppadol P. , Brand Uwe , Seitz Karl , Roth Roland , Zeiss Carl
Published: December 2003

Das weiterentwickelte und optimierte Design eines auf Bulk-Silizium-Technologie basierenden 3-D-Kraftsensors wird beschrieben. In vorangegangenen Untersuchungen konnte gezeigt werden, dass sich dieser Kraftsensor zum Einsatz in der taktilen Wegmesstechnik als Antastsensor eignet. Das Sensorelement besteht aus einer mit mikrotechnischen Herstellungsverfahren gefertigten Silizium-Bossmembran. In diesem Bericht wird ein neues Design und eine neue Auswertungsstrategie für diesen Sensortyp beschrieben.
CAD-Entwurfsumgebung für Mikrokomponenten (CAD Environment for Micro Components)
Authors: Triltsch Udo , Hansen Ulli , Büttgenbach Stephanus
Published: December 2003

In diesem Beitrag wird BICEPS präsentiert, ein T-CAD-Werkzeug zur Unterstützung im Mikrosystementwurf. Ursprünglich zur Steuerung des Kontrollflusses im Entwurfsprozess nasschemisch geätzter Siliziumkomponenten konzipiert, wurde es um ein regelbasiertes Werkzeug zur Analyse und Verifikation von Prozessketten erweitert. Im ersten Teil wird eine Übersicht über die Funktionalität der Entwurfsumgebung gegeben, der zweite Teil konzentriert sich auf die Validierung von Prozessketten.
Kalibrierung von integrierten Drucksensoren im Waferverbund (On-Wafer Calibration for Pressure Sensors)
Authors: Köster Oliver , Slotkowski Johann , Brögger Dirk
Published: December 2003

Die Entwicklung neuer mobiler Systeme wird weiterhin Fortschritte in der Verpackungstechnik von integrierten Schaltungen bewirken und die eingesparte Fläche ermöglicht zusätzliche Produkteigenschaften, welche sich verkaufsfördernd auswirken. So finden sich beispielsweise Höhenmesser und Barometer bereits heute in Uhren und Taschenmessern wieder. Hierzu werden Drucksensoren von hoher Genauigkeit und mit möglichst kleinem Formfaktor herangezogen, d. h. im Idealfall vollständig kalibrierte Drucksensoren für die Flip-Chip-Montage. Für solche Bauelemente sind neue Methoden für die notwendige Kalibrierung zu entwickeln. Im Folgenden wird ein Verfahren für die Kalibrierung von integrierten Drucksensoren im Waferverbund vorgestellt, das am FhG-IMS Duisburg Einsatz findet.
Oberflächentemperaturmessung mit Flüssigkristallen für Strömungsvisualisierung (Surface Temperature Measurement with Liquid Crystals for Flow Visualisation)
Authors: Kaiser Erwin
Published: December 2003

Die Verteilung der Oberflächentemperatur auf überströmten Flächen enthält Informationen über die wandnahe Strömung. Flüssigkeitskristalle und die Auswertung mit der digitalen Bildverarbeitung gestatten Temperaturmessungen für schwierige Messbedingungen. Die effektiven dynamischen Eigenschaften sind abhängig vom Wandmaterial; das wird experimentell und rechnerisch demonstriert. Betrachtet werden pneumatische Impulse sowie Strömungen an einer schnell rotierenden Scheibe und in rotierenden Kammern.
Kalibrierung von Beschleunigungsaufnehmern bei stoßförmiger Anregung und nach dem Vergleichsverfahren (Calibration of Accelerometers with Impact Excitation and Reference Method)
Authors: Müller Heiko
Published: December 2003

In diesem Artikel wird eine Stoßpendel-Einrichtung zur Kalibrierung von Beschleunigungsaufnehmern bei stoßförmiger Anregung im Beschleunigungsbereich 100 m/s2 bis 2000 m/s2 vorgestellt. Einer der größten Einflüsse auf die Messunsicherheit kann die von der Einrichtung erzeugte Querbeschleunigung sein. Es wird gezeigt, wie dieses Problem durch ein neues Stoßschlittenverfahren beseitigt werden kann und welche weiteren Vorteile sich dabei ergeben.
Spektroskopischer Einsatz neuer langwelliger (bis 2 μm) Diodenlaser (VCSEL) für schwierige Bedingungen (Spectroscopic Application of Long-Wavelength (< 2 μm) VCSEL Diode Lasers)
Authors: Lackner Maximilian , Winter Franz , Totschnig Gerhard , Ortsiefer Markus , Rosskopf Jürgen , Amann Markus-Christian , Shau Robert
Published: December 2003

Oberflächenemittierende Diodenlaser (engl. VCSEL, Vertical-cavity surface-emitting laser) werden zur raschen direkten In-situ-Molekülspektroskopie eingesetzt. Nach dem Verfahren der Absorptionsspektroskopie mittels durchstimmbarer Diodenlaser wird Sauerstoff bei 760 nm, Ammoniak bei 1540 nm, Methan bei 1680 nm sowie Chlorwasserstoff und Wasser bei 1810 nm detektiert. Druckverbreiterte und hochaufgelöste Spektren werden gezeigt und das Prinzip eines langzeitstabilen Spektrometers vorgestellt. Die Wellenlängenmodulation der VCSEL mit der Temperatur und dem Strom wird untersucht. Während der Temperaturkoeffizient in etwa derselbe ist wie für herkömmliche Diodenlaser im nahen Infrarot (DFB-Laser), lassen sich VCSEL deutlich weiter mit dem Strom durchstimmen. Darüber hinaus können VCSEL thermisch wesentlich schneller moduliert werden als konventionelle Kantenemitter. Repetitionsraten bis 5 MHz werden demonstriert. Die neu eröffneten Anwendungsfelder im Hinblick auf den weiten, modensprungfreien Durchstimmbereich (Messung bei hohem Druck, mehrere Spezies, Temperaturverteilungen) und die rasche Modulierbarkeit (Messung extrem transienter Prozesse) werden diskutiert. Weiter werden spektroskopisch interessante Eigentümlichkeiten der VCSEL (geringer Schwellstrom und Strombedarf als Vorteil für batteriebetriebene mobile Geräte, Austestmöglichkeit auf der Waferebene) beleuchtet. Die langwelligen VCSEL mit λ > 1 μm auf InP-Basis existieren noch nicht lange. Es wird angenommen, dass diese demnächst verstärkten Einzug in die Molekülspektroskopie halten werden und das Einsatzgebiet von auf Diodenlasern basierenden Geräten beträchtlich nach höheren Drücken und schwierigen Bedingungen hin erweitern werden.
Bestimmung der Aktivitätsverteilung in Gebinden mit geringfügig radioaktivem Material unter Verwendung großflächiger, unkollimierter, feststehender Gamma-Szintillationsdetektoren (Determination of the Distribution of Radioactivity within Waste Crates by Use of Large Area, not Focused, Fixed Plastic Scintillators)
Authors: Franke Erik , Hoppe Dietrich
Published: December 2003

Die Verwendung von großflächigen Gamma-Detektoren zeichnet sich durch hohe Effektivität und damit geringe Messzeit aus. Dagegen sind mit ihnen keine hohen Ortsauflösungen bei der Rekonstruktion der Aktivitätsverteilung möglich. Zur Untersuchung der Rekonstruierbarkeit unbekannter Aktivitätsverteilungen werden zwei in der Tomographie gebräuchliche Verfahren verglichen, ein algebraisches (iterativ) und ein analytisches (gefilterte Rückprojektion). Beide Verfahren erbringen qualitativ ähnliche Ergebnisse. Reale Aktivitätsverteilungen werden nach beiden Verfahren zufriedenstellend rekonstruiert.
Entwicklung einer “künstlichen Nase” zur Geruchsstoff- und Geruchsintensitätserkennung (Development of an Artificial Nose for Odours and Odour Intensity Identification)
Authors: Roßmann Thomas , Platzer Bernd
Published: December 2003

In dieser Arbeit wird der Aufbau einer künstlichen Nase und deren Erprobung beschrieben. Der wesentliche Unterschied zu herkömmlichen elektronischen Nasen besteht darin, dass neben der Geruchsstoffszuordnung in Geruchsklassen auch eine Geruchsintensitätserkennung vorgenommen wird. Dazu werden die Gassensoren direkt der Geruchsfahne ausgesetzt und neben den Messsignalen der Gassensoren auch die Überströmgeschwindigkeit in den eingesetzten künstlich-neuronalen Netzen (KNN) verarbeitet. Die verwendeten Gassensoren, die elektronische Schaltung und die KNNs werden getestet.
Value‐at‐risk for long and short trading positions
Authors: Giot Pierre , Laurent Sébastien
Published: December 2003

In this paper we model Value‐at‐Risk (VaR) for daily asset returns using a collection of parametric univariate and multivariate models of the ARCH class based on the skewed Student distribution. We show that models that rely on a symmetric density distribution for the error term underperform with respect to skewed density models when the left and right tails of the distribution of returns must be modelled. Thus, VaR for traders having both longand shortpositions is not adequately modelled using usual normal or Student distributions. We suggest using an APARCH model based on the skewed Student distribution (combined with a time‐varying correlation in the multivariate case) to fully take into account the fat left and right tails of the returns distribution. This allows for an adequate modelling of large returns defined on long and short trading positions. The performances of the univariate models are assessed on daily data for three international stock indexes and three US stocks of the Dow Jones index. In a second application, we consider a portfolio of three US stocks and model its long and short VaR using a multivariate skewed Student density. Copyright © 2003 John Wiley & Sons, Ltd.
A practical log‐linear aggregation method with examples: heterogeneous income growth in the USA
Authors: Albuquerque Pedro H.
Published: December 2003

A practical aggregation method for heterogeneous log‐linear functions is presented. Inequality measures are employed in the construction of a simple but exact aggregate representation of an economy. Three macroeconomic applications are discussed: the aggregation of the Lucas supply function, the time‐inconsistent behaviour of an egalitarian social planner facing heterogeneous discount rates, and the case of a simple heterogeneous growth model. In the latter application, aggregate CPS data is used to show that the slowdown that followed the first oil shock is worse than usually thought, and that the ‘new economy’ growth resurgence is not as strong as it appears.

The reaction of one man could be forecast by no known mathematics; the reaction of a billion is something else again.—Foundation and Empire, Isaac Asimov (1952)

Copyright © 2003 John Wiley & Sons, Ltd.
Bayesian inference for the mover–stayer model in continuous time with an application to labour market transition data
Authors: Fougère Denis , Kamionka Thierry
Published: December 2003

This paper presents Bayesian inference procedures for the continuous time mover–stayer model applied to labour market transition data collected in discrete time. These methods allow us to derive the probability of embeddability of the discrete‐time modelling with the continuous‐time one. A special emphasis is put on two alternative procedures, namely the importance sampling algorithm and a new Gibbs sampling algorithm. Transition intensities, proportions of stayers and functions of these parameters are then estimated with the Gibbs sampling algorithm for individual transition data coming from the French Labour Force Surveys collected over the period 1986–2000. Copyright © 2003 John Wiley & Sons, Ltd.
A hybrid approach to dynamic‐wavelength blocking/equalizing and optical‐power monitoring
Authors: Xiao Gao Zhi , Sun Feng Guo , Lu Zhenguo , Zhang Zhiyi , Zhao Ping , Grover Chander P.
Published: December 2003

In optical communication systems, dynamic wavelength blocking/equalizing and power monitoring are two inseparable functions, but they are provided by two individual modules. This paper describes a hybrid‐integration approach to dynamic‐wavelength blocking/equalizing and optical power monitoring, which provides advantages such as higher wavelength blocking efficiency and lower fabrication cost. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 95–96, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11295
Numerical investigation of the effective dimensions of perfect electric conductor (PEC) in FDTD simulation
Authors: Zhou Baixin , Wang Sicong , Yu Wenhua
Published: December 2003

In this communication, we present an improvement technique for the finite‐difference time‐domain (FDTD) method, in which an accurate solution can be achieved using a very coarse mesh if a weighted factor of the simulated PEC object dimension is properly selected. A uniform microwave stripline is used to validate the proposed scheme. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 107–109, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11298
A multistructure method of moments for EM optimization
Authors: Cormos Délia , Loison Renaud , Gillard Raphaël
Published: December 2003

In this paper, a novel fast computation technique based on the method of moments (MoM) is introduced. The principle of the proposed technique consists in the simultaneous analysis of different structures using only one MoM matrix. The formulation is absolutely rigorous and leads to important time savings, in comparison with equivalent direct MoM simulations. First results are given for 1D structures and the applicability for EM optimization is discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 114–117, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11301
Performance improvement of transmission of 10 Gb/s DML in metro area network
Authors: Ma Xiaohong , Li Yanhe , Zhang Hanyi , Guo Yili , Li Yanan , Yu Jinlong , Yang Enze
Published: December 2003

A novel method to improve the performance of 10‐Gb/s directly modulated laser (DML) transmission along single‐mode fiber (SMF) in a metro‐area network (MAN) is proposed. It is demonstrated that by adapting the filter with a special central frequency shift and suitable bandwidth, the dispersion power penalty can be effectively reduced. A distance limit of 10 Gb/s DML along SMF is extended to 51 km in simulation and elementary experiment. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 130–132, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11306
Investigation of the output characteristics of multi‐wavelength lasers based on SOAs and sampled fiber gratings
Authors: Zhang Xinliang , Sun Junqiang , Liu Deming , Huang Dexiu
Published: December 2003

A novel scheme for multiwavelength lasers, based on semiconductor optical amplifiers (SOAs) and cascaded two‐sectional sampled fiber gratings (SFGs), is analyzed theoretically and experimentally. Reflection spectra for sampled fiber gratings and lasing output spectra for multiwavelength lasers are calculated based on a corresponding theoretical model. By exploiting SOAs and sampled fiber gratings, a multiwavelength laser with 11 channels is specially designed, and an output‐power difference of less than 1 dB is demonstrated. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 142–146, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11308
On the duality of electric and magnetic fields using the nonstandard FDTD method
Authors: Taguchi Kenji , Sendo Yuuki , Kashiwa Tatsuya , Ohtani Tadao , Kanai Yasushi
Published: December 2003

Verifying the duality of electric and magnetic fields using the nonstandard FDTD method is important for far‐field calculations using the equivalence principle and for the reduction of reflection from boundaries of different size lattices. In this paper, the duality of the fields using this method is confirmed in both physically and numerically. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 148–151, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11310
Achieving flat output power of a tunable EDFL utilizing fiber‐loop mirrors in a linear cavity
Authors: Bouzid B. , Mohammed H. , Mahdi M. A. , Abdullah M. K.
Published: December 2003

A novel configuration of erbium‐doped fiber laser using fiber‐loop mirrors in a linear cavity that produces flat output power is demonstrated. Maximum output power of about 14 dBm with 0.7‐dB flatness is obtained from 1525 to 1565 nm without altering the cavity loss. A side‐mode suppression ratio of higher than 60 dB, where the noise floor generated from the laser system is efficiently suppressed, is obtained. No significant presence of residual amplified spontaneous emission at the output is observed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 151–153, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11311
A highly nonlinear dispersion‐shifted fiber with 9.3 μm2 effective area and low loss for all fiber wavelength converter
Authors: Chung Kun‐Wook , Yin Shizhuo
Published: December 2003

In this paper, a new highly nonlinear dispersion‐shifted fiber (HN‐DSF) with an effective area of 9.3 μm2 is presented. This innovative HN‐DSF has a unique triple‐cladding structure, which offers not only a large nonlinear coefficient, but also low attenuation, low splicing, and bending losses. It is a very suitable candidate to implement an all‐fiber wavelength converter via four‐wave mixing (FWM). © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 153–156, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11312
Comparison of grating analysis techniques for SG‐DBR lasers
Authors: Wimpenny G. , Adams M. J.
Published: December 2003

Two techniques to locate the wavelengths of the main reflectivity peaks of a sampled grating used as part of a sampled‐grating distributed Bragg reflector (SG‐DBR) laser are presented. It is shown that the results are in good agreement and also consistent with the theoretical results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 161–164, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11316
High‐efficiency class‐C power‐amplifier module
Authors: Song Ki‐Jae , Lee Jong‐Chul , Lee Byungje , Kim Jong‐Heon , Kim Nam‐Young
Published: December 2003

This paper presents the design of a high‐efficiency LDMOS power‐amplifier module (PAM) at the 880‐MHz band. The nonlinear parameters for the LDMOS FET are obtained through the modified SPICE level‐3 static and large‐signal analyses. It shows an output power of 30.2 dBm and power‐added efficiency (PAE) of 64%, with a transducer power gain of 28.78 dB. In this paper, the harmonic‐trap network (HTN) is introduced to maximize the PAE and the winding transmission line (WTL) is adopted to obtain the optimizing output matching point between the output power and PAE. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 164–167, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11317
Performance analysis of the all‐optical XOR gate using SOA‐MZI with a differential modulation scheme
Authors: Wang Ling , Zhang Min , Zhao Yongpeng , Ye Peida
Published: December 2003

In this paper, the all‐optical exclusive OR gate using an integrated SOA‐based Mach–Zehnder interferometer with a differential modulation scheme is proved to exceed the operation speed limit effectively through numerical analysis for the first time. The control‐signal pulse parameters and delay time are discussed and designed to optimize the performance of the XOR gate. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 173–177, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11320
Prenatal imaging of facial clefts by magnetic resonance imaging with emphasis on the posterior palate
Authors: Ghi Tullio , Tani Giovanni , Savelli Luca , Colleoni Giulia Gandolfi , Pilu Gianluigi , Bovicelli Luciano
Published: December 2003

Objective

To evaluate the role of Magnetic Resonance Imaging (MRI) in the prenatal diagnosis of facial clefts.

Materials and Methods

Six fetuses with a sonographic diagnosis of cleft lip and palate underwent MRI at a median age of 30 weeks (range 28–32). The defect was bilateral in two cases.

Results

Fetal MRI confirmed the presence of a cleft involving at least the anterior palate in all cases. Distinction between unilateral and bilateral clefts could be made in all cases and was always confirmed after birth. Sagittal views of the fetal face were found to be particularly useful in identifying the degree of extension of the cleft into the palate. The diagnosis was confirmed after birth.

Conclusion

Our results suggest that MRI may be ancillary to ultrasound in prenatal investigation of a fetus with cleft lip, allowing a better staging of the lesion by demonstrating the degree of involvement of the palate. Copyright © 2003 John Wiley & Sons, Ltd.
Prenatal diagnosis of sacrococcygeal teratoma with constitutional partial monosomy 7q/trisomy 2p
Authors: Le Caignec C. , Winer N. , Boceno M. , Delnatte C. , Podevin G. , Liet J. M. , Quere M. P. , Joubert M. , Rival J. M.
Published: December 2003

We report the prenatal diagnosis of a fetus with sacrococcygeal teratoma and facial dysmorphism attributed to a constitutional terminal deletion of chromosome 7q and partial trisomy of chromosome 2p likely resulting from a de novo balanced translocation. The cytogenetic abnormality was diagnosed prenatally after sonographic detection of teratoma and confirmed on peripheral blood cells at birth. The newborn died of post‐operative complications at seven days of age. FISH analysis demonstrated haploinsufficiency of HLXB9, a gene identified in the triad of a presacral mass (teratoma or anterior meningocele), sacral agenesis, and anorectal malformation, which constitutes the Currarino syndrome. Despite the absence of other features of the triad, the teratoma observed in the fetus we describe might represent a partial form of Currarino syndrome. Copyright © 2003 John Wiley & Sons, Ltd.
Prenatal diagnosis of Apert syndrome: report of two cases
Authors: Skidmore David L. , Pai Aditya P. , Toi Ants , Steele Leslie , Chitayat David
Published: December 2003

Two de novo cases with Apert Syndrome detected prenatally are presented herein. In the first, fetal ultrasound findings of syndactyly of the hands, craniosynostosis and proptosis resulted in a prenatal diagnosis in the nineteenth week of gestation. This is the earliest prenatal diagnosis of this syndrome in a not‐at‐risk case. Following counseling, this pregnancy was terminated and subsequent pathological examination and DNA analysis confirmed the diagnosis of Apert Syndrome and coarctation of the aorta. In the second case, fetal ultrasound at 21 weeks' gestation revealed a hypoplastic left heart and clover‐leaf skull. Following counseling, this pregnancy was also terminated. Further examination of the fetus and DNA analysis led to a diagnosis of Apert Syndrome. These cases emphasize the need to complete a thorough fetal ultrasound in cases with potentially lethal cardiac abnormality and the importance of incorporating a fetal pathologist, as well as a medical geneticist, in the investigations performed after delivery or pregnancy termination when a fetal abnormality is detected on ultrasound. Copyright © 2003 John Wiley & Sons, Ltd.
Adverse pregnancy outcomes associated with maternal enalapril antihypertensive treatment
Authors: Tabacova Sonia , Little Ruth , Tsong Yi , Vega Amarilys , Kimmel Carole A.
Published: December 2003

Background

Adverse pregnancy outcomes following the use of angiotensin‐converting enzyme (ACE) inhibitors, including enalapril, have been reported in descriptive studies. However, no analytical studies on the relationship between the adverse outcomes and enalapril gestational exposures are available.

Objectives

To explore the association between enalapril exposure and adverse outcomes in pregnancy, taking into account other possible risk factors.

Methods

We analyzed a series of all usable cases reported to the FDA between 1986 and 2000 in which enalapril was a suspect drug for the observed adverse outcomes (N = 110). Parameters of exposure and reported outcomes as well as information on potentially confounding variables were systematically abstracted from this series by a single physician. Because exposure to ACE inhibitors after the first trimester of pregnancy had been associated with adverse outcomes in the existing literature, we divided the cases into those exposed in the first trimester only (considered as the baseline group) and cases exposed beyond or after this time. Frequency of reported adverse outcomes in the second group was compared with those in the baseline group; odds ratios were computed, taking account of potentially confounding variables by logistic regression where appropriate.

Results

Exposure to enalapril after the first trimester of pregnancy was strongly associated with oligohydramnios and specific adverse outcomes thought to be secondary to reduced amniotic fluid volume (limb deformities, cranial ossification deficits, lung hypoplasia), as well as with neonatal renal failure. The relationship did not change after taking numerous potential confounders into account, including duration of exposure, concomitant drug use, maternal age, concurrent disease, neonatal gender, and gestational age at birth. Such a pattern of abnormalities is considered to be a consequence of the effect of ACE inhibition on fetal renal function that develops after the first trimester.

Conclusion

The specificity and temporality of the observed adverse manifestations suggest a causal relationship to enalapril exposure. Copyright © 2003 John Wiley & Sons, Ltd.
Patient approach and experience regarding complementary medicine: survey among hospitalized patients in a university hospital
Authors: Rosen Irit , Azzam Zaher S. , Levi Tiferet , Braun Eyal , Krivoy Norberto
Published: December 2003

Purpose

To characterize the local population that turns to complementary medicine.

Methods

Participants were selected randomly: Medicine [A] (201 patients); Surgery [B] (100 patients); Control [C] (128 patients). The answers to the first two questions determined whether the questionnaire was to be completed.

Results

More females sought complementary medicine treatment, with no significant demographic differences among the groups. Nearly 20% of the subjects had academic education while 43% had completed high school. The results of the 16 significant questions were statistically different when comparing groups C and A (p = 0.025) and B (p = 0.011) respectively. A total of 16%, 12.4% and 9% of the subjects respectively preferred a physician MD as their complementary medicine practitioner and 49% [C], 34% [A] and 29% [B] respectively, favored teaching complementary medicine in medical and nursing schools.

Conclusions

A total of 37% [C], 21% [B] and 27% [A] of the subjects experienced complementary medicine intervention at least once. The percentage of individuals holding academic degrees was higher in the group utilizing complementary medicine than those who did not. Only 21% of C and A groups and 12% of B group knew about adverse reactions to complementary therapies. More than 30% favored ‘legalizing’ complementary medicine. Copyright © 2003 John Wiley & Sons, Ltd.
Do doctors rely on pharmaceutical industry funding to attend conferences and do they perceive that this creates a bias in their drug selection? Results from a questionnaire survey
Authors: Rutledge Philip , Crookes David , McKinstry Brian , Maxwell Simon R. J.
Published: December 2003

Purpose

To determine the sources of funding for doctors attending conferences and meetings and the doctors' perception on whether their involvement with the pharmaceutical industry created a conflict of interest or bias in their drug selection.

Method

A postal questionnaire was distributed to 622 hospital doctors and 515 general practitioners (GPs) working in the Edinburgh area in Scotland, UK.

Results

The pharmaceutical industry funded approximately half of the meetings and conferences attended by doctors. Less than 20% of the doctors funded themselves. One‐third of the meetings would not have been attended if funding from the industry had not been available. Hospital doctors and GPs had similar views on conflict of interest and bias. A minority of doctors (40%) thought that industry involvement created a conflict of interest but the majority of doctors (86%) thought that it did not create a bias in their own drug selection.

Conclusions

If continuing medical education (CME) for doctors is going to rely on pharmaceutical industry funding in the future, then we need more explicit codes of conduct. It is of concern that while many doctors recognise the potential for the industry to influence their prescribing habits, few recognise that they themselves are susceptible. Copyright © 2003 John Wiley & Sons, Ltd.
Calculation of one‐center integrals in parametric methods using simulated annealing and simplex methods
Authors: Ruette F. , Sánchez M. , Mendoza C. , Sierraalta A. , Martorell G. , González C.
Published: December 2003

A methodology to compute the one‐center integrals required for molecular calculations in parametric methods is presented. It is based on the simulated annealing technique combined with the simplex method, which are used to calculate parameterized one‐center integrals in atomic systems. It is found that for an adequate selection of electronic states it is possible to obtain a set of parameters that reproduce accurately the experimental atomic excitation energies. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Vibrational and electronic contributions to the polarizability and first hyperpolarizability of monosubstituted acetylene: Theoretical study
Authors: Saal Amar , Ouamerali Ourida
Published: December 2003

The two contributions, vibrational and electronic, to the electrical properties polarizability and first hyperpolarizability of monosubstituted acetylene HCCX (with X = F, Cl, Br, OH, SH, BH2, NH2, CH3, and SiH3) have been evaluated using the self‐consistent field wave functions within the double‐harmonic oscillator approximation. The results show that both contributions to the electrical properties are sensitive to the nature of the substituent: electronegativity, atomic volume, and X‐weight. In some cases, X = NH2, SiH3, and SH, the nonlinear optical response is essentially due to, and only to, the vibrational response β of the molecule. A complete study is made upon two tracks, upon the intrinsic properties of X and upon the IR and Raman spectra as well as the sum‐over‐modes expression. We also calculated the electrical properties at the AUG‐cc‐pVDZ basis set and at geometric parameters optimized at different levels of theory (B3LYP and MP2). © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
C1C2 bond cleavage in vinylidenecyclopropanes: Theoretical density functional theory study
Authors: Zhanpeisov Nurbosyn U. , Mizuno Kazuhiko , Anpo Masakazu , Leszczynski Jerzy
Published: December 2003

Density functional calculations at the B3LYP/6‐31G* level were carried out to investigate the photo rearrangements in 1,1‐diarylvinylidene‐2,3‐dimethyl‐ and 1,1‐diarylvinylidene‐2,2,3,3‐tetramethylcyclopropanes. Among the five different routes considered, none except the one leading to the final products of butatriene derivatives (route 4) was found to be able to explain the experimental findings only. However, the route 4 points out on the involvement of the C1C2 bond cleavage in strained cyclopropane ring. Thus, a new mechanism that results in successive transformations was suggested to explain this distinct C1C2 bond cleavage in cyclopropane ring for both precursors leading to formation of butatriene derivatives. The results of calculations indicate that photochemistry of vinylidenecyclopropane derivatives is significantly different than in the case of methylenecyclopropane compounds. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Studies of metal isotope and deuteration effects in vibrational spectra of palladium(II) complex with histamine
Authors: Drożdżewski Piotr M. , Kordon Ewa , Roszak Szczepan
Published: December 2003

Vibrational spectra of the palladium(II) complex with histamine were studied within the density functional theory (DFT) formalism. In addition, frequency shifts due to N‐deuteration and isotopic Pd104 on Pd110 replacement were determined theoretically and compared with those measured. All spectra were supplemented by the potential energy distribution analysis. The theoretical results were applied to the complete band assignment of newly and previously measured spectra. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Theoretical study of the energetic and possible intermediates of the CH3CH2O2 self‐reaction
Authors: Feria Leticia , Gonzalez Carlos , Castro Miguel
Published: December 2003

By means of ab initio and density functional theory methods we have studied the geometry and electronic structure of the ethyl peroxyl radical, CH3CH2O2, and of the tetraoxide intermediates, CH3CH2O4CH2CH3, involved in the self‐reaction of this radical. These kinds of reactions may occur in the troposphere and, depending on the structure of the intermediates, the following pathways are originated: (I) 2CH3CH2O2 → 2CH3CH2O + O2, (II) 2CH3CH2O2 → CH3CH2OH + CH3CHO + O2, and (III) 2CH3CH2O2 → CH3CH2O2CH2CH3 + O2. The energetic of these three reactions was also addressed. With the aid of the Gaussian 98 package, full geometry optimizations, electronic structure, vibrational frequencies, and total energies were determined for reactives, intermediates, and products of each pathway. Calculations, of the all‐electron type, were done at the Hartree–Fock (HF), MP2, and B3LYP levels of theory using 6‐311G(2d,2p) orbital basis sets. It was found that the B3LYP results, for the enthalpy of the reactions, ΔHr, are in better agreement with the experiment than the HF and PMP2 estimates. Indeed, the ΔHr for paths I and II, including zero‐point energies, are +2.3 and −80.2 kcal/mol, respectively, which compares well with the experimental values: +5.5 and −82.0 kcal/mol. Our prediction for ΔHr of path III is −29.7 kcal/mol. Moreover, three intermediates, A, B, and C, of different geometry and energy were found. The structure of each intermediate is closely connected with the products obtained in each reaction path, as determined experimentally. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
MCSCF study of the thermal isomerization of tricyclo[2.1.0.02,5]pentane to 1,3‐cyclopentadiene
Authors: Davis Steven R. , Qin Changyong , Zhao Zhendong
Published: December 2003

The isomerization of tricyclo[2.1.0.02,5]pentane to 1,3‐cyclopentadiene was studied using ab initio calculations at the multiconfiguration self‐consistent field level of theory. Single‐point energy calculations were also performed using the MCQDPT2 and CCSD(T) methods. The isomerization process was found to proceed through a concerted, asynchronous pathway characterized as a disrotatory ring opening of the bicyclobutane moiety. The activation barrier was found to be 42 kcal/mol. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Dimensions of autonomy: Primary teachers' decisions about involvement in science professional development
Authors: Schibeci Renato A. , Hickey Ruth L.
Published: December 2003

Professional development (PD) for primary science teachers is recognized as an important activity which can support improved science education for students. Analysis of interviews with practicing primary science teachers is used to identify the range of PD experiences of a sample of teachers from Western Australia. Teachers' reasons for attending or avoiding science‐related PD are categorized as “decision issues” which include opportunity, compulsion, convenience, enticement, interest, recommendation, and relevance. Case studies describe the interplay of these issues, which result in teachers' attendance or avoidance of PD. A subset of the sample is used to explore teachers' views of other activities which they recognize as contributing to their science teaching, content knowledge, and pedagogy. These other activities include hobbies, partner's job, and pursuing students' interests. Legitimating teachers' own interests as a source of personally derived PD is supported as an avenue to increase the diversity of topics studied by students and to increase the level of content knowledge held by teachers. © 2003 Wiley Periodicals, Inc. Sci Ed 88:119–145, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.sce10091
Real options reasoning and a new look at the R&D investment strategies of pharmaceutical firms
Authors: Gunther McGrath Rita , Nerkar Atul
Published: December 2003

Real options reasoning (ROR) is a conceptual approach to strategic investment that takes into account the value of preserving the right to make future choices under uncertain conditions. In this study, we explore firms' motivations to invest in a new option. We find, based on an analysis of a large sample of patents by firms active in the pharmaceutical industry, that their investments in R&D are consistent with the logic of ROR. We identify three constructs—scope of opportunity, prior experience, and competitive effects—which have an influence on firms' propensity to invest in new R&D options and which could usefully be incorporated in a strategic theory of investment. Copyright © 2003 John Wiley & Sons, Ltd.
Capabilities, business processes, and competitive advantage: choosing the dependent variable in empirical tests of the resource‐based view
Authors: Ray Gautam , Barney Jay B. , Muhanna Waleed A.
Published: December 2003

A growing body of empirical literature supports key assertions of the resource‐based view. However, most of this work examines the impact of firm‐specific resources on the overall performance of a firm. In this paper it is argued that, in some circumstances, adopting the effectiveness of business processes as a dependent variable may be more appropriate than adopting overall firm performance as a dependent variable. This idea is tested by examining the determinants of the effectiveness of the customer service business process in a sample of North American insurance companies. Results are consistent with resource‐based expectations, and they show that distinctive advantages observable at the process level are not necessarily reflected in firm level performance. The implications of these findings for research and practice are discussed along with a discussion of the relationship between resources and capabilities, on the one hand, and business processes, activities, and routines, on the other. Copyright © 2003 John Wiley & Sons, Ltd.
Cloning and sequence analysis of the TRP1 gene encoding the phosphoribosyl anthranilate isomerase from Pichia anomala (strain K)
Authors: Friel Damien , Vandenbol Micheline , Haïssam Jijakli M.
Published: December 2003

Pichia anomala (strain K) is an efficient biocontrol agent against post‐harvest diseases affecting apples. To study the role of strain K genes in biocontrol activity, it is useful to identify selectable markers on which to base a gene disruption strategy. The Pichia anomala TRP1 gene (PaTRP1) was isolated by complementation of the multi‐auxotrophic S. cerevisiae strain FY‐1679‐18b. DNA sequence analysis revealed the presence of a 699 bp ORF encoding a 233 amino acid protein showing the typical conserved structure of proteins of the phosphoribosyl anthranilate isomerase (PRAI) family. Codon analysis revealed a high number of unused codons. Downstream from PaTRP1 was found the 3′ extremity of a gene highly similar to the IPP1 gene (coding for the inorganic pyrophosphatase). In addition, a sequence of the 5′ extremity of the insert is highly similar to a fragment of the S. cerevisiae PRP9 gene, coding for a spliceosome‐associated protein. The nucleotide sequence has been deposited in the Genbank database under Accession No. AY198188. Copyright © 2003 John Wiley & Sons, Ltd.
Physical and sexual abuse of women before, during, and after pregnancy
Authors: Guo S.F , Wu J.L , Qu C.Y , Yan R.Y
Published: December 2003

Objectives: To examine patterns of physical and sexual abuse before, during, and after pregnancy. Methods: A community‐based interview survey of a representative group of women with children aged 6–18 months was carried out between November 1, 2001, and February 28, 2002, in 32 communities of the Tianjing, Liaoning, Henan, and Shannxi provinces. Results: The overall prevalence of physical and sexual abuse (occurring before, during, and after pregnancy) was 11.7%. The prevalence of physical and sexual abuse before pregnancy was 8.5%, compared with 3.6% during pregnancy and 7.4% during an average postpartum period of 11 months. Abuse before pregnancy was a strong indicator of abuse during pregnancy and after delivery, and abuse during a previous period was a strong indicator of subsequent abuse. Most abuse was recurrent and not severe. Conclusion: Routine screening for abuse in the maternity services setting is advocated to decrease the effect of abuse on women and their children.
Intrapartum fetal pulse oximetry and fetal heart rate decelerations
Authors: Puertas A. , Navarro M. , Velasco P. , Montoya F. , Miranda J.A.
Published: December 2003

Objectives: To determine the behavior of fetal oxygenation (FSpO2) in different patterns of fetal heart rate decelerations (FHR). Methods: A total of 787 decelerations were studied. Results: FSpO2 decreased significantly during decelerations, especially when the alteration was prolonged. Conclusions: Modifications in FHR occur simultaneously with alterations in FSpO2, although the latter do not persist in time. Different degrees of FSpO2 seen prior to deceleration are an expression of fetal respiratory status.