bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoluminescence of a ‐plane GaN: comparison between MOCVD and HVPE grown layers
Authors: Paskov P. P. , Schifano R. , Malinauskas T. , Paskova T. , Bergman J. P. , Monemar B. , Figge S. , Hommel D. , Haskell B. A. , Fini P. T. , Speck J. S. , Nakamura S.
Published: May 2006

We report on the emission properties of nonpolar a ‐plane GaN layers grown by metalorganic chemical vapor deposition (MOCVD) and hydride vapor phase epitaxy (HVPE). Together with the typical band edge exciton emission, the low‐temperature photoluminescence spectra reveal several emission bands in the spectral range 3.29‐3.42 eV. These emissions appear with different intensities in layers grown by different techniques and show different thermal quenching and recombination dynamics. The 3.42 eV and 3.35 eV emissions are found to be of an intrinsic origin and are associated with carriers localized at stacking faults. The emission at 3.29 eV, which is present only in MOCVD layers, shows a donor‐acceptor pair behavior suggesting that impurities attached to structural defects are involved. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Current crowding effects on blue LED operation
Authors: Evstratov I. Yu. , Mymrin V. F. , Karpov S. Yu. , Makarov Yu. N.
Published: May 2006

A hybrid 1D/3D approach to modeling of the electric current spreading in a light emitting diode (LED) die is suggested and validated by comparing the theoretical predictions with available observations. Large‐area LEDs with different contact electrode configurations suitable for high‐power operation are analyzed in terms of simulations with the focus on the current non‐uniformity and its impact on the device electrical and optical characteristics. The factors controlling the LED series resistance are identified by modeling, and ways for the resistance improvement are examined. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A surface trap model and its application to analysis of III‐nitride HEMT performance
Authors: Bulashevich Kirill A. , Karpov Sergey Yu.
Published: May 2006

A polarity‐dependent model of electron/hole traps on a free GaN:Si surface is suggested, accounting for both intrinsic and impurity‐induced surface states. The model parameters are fitted to provide the best agreement with available observations. The suggested approach is invoked to explain a recently observed non‐monotonic dependence of the surface barrier due to band bending upon the donor concentration in the GaN bulk. The model is used for analysis of DC performance of high‐electron mobility transistors (HEMTs) with different cap layer design. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radio‐frequency MBE growth of cubic GaN on 3C‐SiC(001)/Si(001) template
Authors: Ohachi T. , Kikuchi T. , Somintac A. , Yamaguchi S. , Yasuda T. , Wada M.
Published: May 2006

A 3C‐SiC(001) was formed by coincidence site lattice matching on Si(001) through carbonization using acetylene (C2H2) supplied by a jet nozzle. The 3C‐SiC serves as a cubic template for the MBE growth of c‐GaN on Si substrates. The Si substrate with lattice constant of a Si = 0.544 nm was covered with strained 3C‐SiC whose lattice constant a 3C‐SiC/Si = 0.445 nm expanded from that of the bulk 3C‐SiC crystal (0.438 nm). Better quality cubic phase GaN film was grown on the strained 3C‐SiC template layer when the Ga/N flux ratio approached unity of Ga rich side. The proportion of the cubic phase in the GaN layer was calculated to be 94.7% from the integrated intensity ratio of the X‐ray diffraction peaks of c‐GaN(002) and h‐GaN(10‐11). The FWHM of the (002) diffraction peak for the 544 nm‐thick c‐GaN was 13.2 arcmin. A precise RHEED analysis also indicated that the c‐GaN had (2x2) surface reconstruction structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of InGaN/GaN quantum wells on sapphire and bulk GaN substrate
Authors: Dworzak M. , Stempel T. , Hoffmann A. , Franssen G. , Grzanka S. , Suski T. , Czernecki R. , Leszczynski M. , Grzegory I.
Published: May 2006

We investigated the recombination dynamics in InGaN quantum well (QW) structures, grown by metal organic chemical vapour deposition on sapphire and bulk GaN crystals. We present the results of time‐integrated and time‐resolved photoluminescence (PL) spectroscopy performed on single QWs with widths of 4.5 nm and 9.5 nm. The recombination mechanisms were studied at 5 K and elevated temperatures up to room temperature. Radiative and nonradiative life‐times were determined. The luminescence properties are strongly influenced by the localization of excitons in a complex potential landscape with localization sites of varying depth. Redistribution of charges from shallow to deeper localization sites were observed. The band profile fluctuations influence the thermal stability of the luminescence. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Large enhancement of GaN‐UV light emission using silver mirror resonator
Authors: Ahmed N. M. , Hashim M. R. , Hassan Z.
Published: May 2006

In this paper we used new microcavity resonator design of extracting light with high efficiency from a high index material (GaN), n > 2 for use in light emitting diode (LED) and laser diode (LD). A GaN/sapphire structure as an active layer was sandwiched between two silver mirrors. For the study two types of microcavity were fabricated: (air/GaN/sapphire/silver) and (silver/GaN/sapphire/silver). Via photo‐luminescence measurements we observed 2‐fold intensity enhancement in the UV region (364 nm) at room temperature by using 400 nm silver back mirror compared with uncoated sample. The amplitude of the photoluminescence is enhanced 10‐times when we used 400 nm back coated together with 50 nm silver as front mirror. Further, a tremendous enhancement was obtained when a small hole was made in the front mirror with 50 nm thickness. The large increment of GaN/sapphire light emission in this microcavity could be caused by few important factors: increasing absorption in the cavity, optical field enhancement due to the resonator and coupling of plasmon in the metallic layer with the UV light. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diffraction anomalous fine structure investigation of InGaN quantum dots
Authors: Piskorska E. , Holý V. , Siebert M. , Krause B. , Metzger T. H. , Schmidt Th. , Falta J. , Yamaguchi T. , Hommel D.
Published: May 2006

Diffraction anomalous‐fine structure technique was used for the investigation of the chemical composition of self‐assembled non‐capped InGaN quantum dots grown on GaN. In a grazing‐incidence geometry, a dependence of the energy of the GaK absorption edge on the radial scattering vector was found. This dependence is explained by a chemical shift of the GaK absorption edge due to the In content and due to the local elastic strains in quantum dots. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton dynamics in nonpolar (11$ \bar 2 $0) InGaN/GaN multiple quantum wells grown on GaN templates prepared by lateral epitaxial overgrowth
Authors: Onuma T. , Chakraborty A. , Haskell B. A. , Keller S. , Sota T. , Mishra U. K. , DenBaars S. P. , Speck J. S. , Nakamura S. , Chichibu S. F.
Published: May 2006

Exciton dynamics in nonpolar (11‐20) InxGa1–xN/GaN multiple quantum wells (QWs) grown on GaN templates prepared by lateral epitaxial overgrowth were studied. Due to the absence of the polarization fields normal to the QW plane, the photoluminescence (PL) peak energy moderately shifted to the higher energy and the radiative lifetime did not change remarkably with the decrease in the well thickness. Similar to the case for polar InGaN QWs, time‐resolved PL signals exhibited the nonexponential decay shape, which can be explained by thermalization and subsequent localization of excitons. Although the growth conditions were not fully optimized, values of the PL intensity at 300 K divided by that at 8 K were 25 and 17% for the peaks at 2.92 and 2.60 eV, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MOCVD of InGaN‐based light emitting structures on silicon substrates with strain optimized buffer layers using long Al pre‐deposition
Authors: Clames J.‐Y. , Giesen Ch. , Meyer T. , Heuken M.
Published: May 2006

GaN/InGaN multi quantum wells (MQWs) were grown on silicon (Si) substrates by Metalorganic Vapor Phase Epitaxy (MOVPE). A structure of layers consisting of AlN, AlGaN and GaN was used for subsequent deposition of the MQW structures on Si substrates. The Al pre‐deposition time before growing the buffer structure and its effect on the formation of cracks was investigated. The emitted wavelength of the structure was changed by varying the thickness of the Mg‐doped AlGaN electron blocking layer, by reducing the growth temperature of the MQW structure and by increasing the QW width of the structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlGaN epitaxial layers grown by HVPE on sapphire substrates
Authors: Soukhoveev V. , Kovalenkov O. , Shapovalova L. , Ivantsov V. , Usikov A. , Dmitriev V. , Davydov V. , Smirnov A.
Published: May 2006

Growth of AlxGa1–xN (x ∼ 0.0‐1.0) alloy layers by hydride vapor pahse epitaxy (HVPE) is reported. Crack‐free undoped AlGaN layers from 0.1 to 2 μm thick were grown on 2″ SiC and 2″and 4″ sapphire substrates. For AlxGa1–xN (x ∼ 0.7‐0.8) layers grown on sapphire, high‐resolution symmetric/asymmetric X‐ray diffraction (XRD) measurements resulted in ω‐scan rocking curve widths ranging from 250 to 650 arcsec and from 1400 to 1900 arcsec, for the (00.2) and (10.2) reflections, respectively. Minimum XRD‐estimated screw and edge dislocation densities in AlGaN layers grown on sapphire were <6 x 108 cm–2 and <2 x 109 cm–2, respectively. Raman studies revealed that the composition dependences of the phonon modes of HVPE‐grown AlxGa1–xN layers are in a good agreement with the one, which have been observed for MOCVD‐grown AlxGa1–xN alloys earlier. Grown layers had n‐type electrical conductivity for the composition range up to x = 0.4. The layer became highly resistive for higher AlN contents. First results on 40 µm thick crack free AlGaN growth on SiC substrates are reported. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carrier confinement effect enhanced by AlGaN/GaN multi‐quantum barrier in AlInGaN based high power blue‐violet laser diodes
Authors: Lee Sung‐Nam , Cho S. Y. , Ha K. H. , Choi K. K. , Jang T. , Chae S. H. , Kim H. K. , Paek H. S. , Sung Y. J. , Sakong T. , Son J. K. , Ryu H. Y. , Kim Y. H. , Yoon E. , Nam O. H. , Park Y.
Published: May 2006

AlGaN/GaN multi‐quantum barriers (MQBs) were firstly introduced into violet AlInGaN laser diodes with InGaN multi‐quantum wells structure, resulting in drastic improvements in lasing performance. Comparing with conventional AlGaN single electron blocking layer (EBL), lower threshold current and higher slope efficiency at room temperature could be achieved by AlGaN/GaN multiquantum barrier. It can be explained that p‐type AlGaN/GaN MQBs is more effective to suppress the overflow of electron than single p‐type AlGaN EBL by the increase of effective barrier heights due to the quantum effect of MQB and the enhancement of p‐type doping efficiency. Additionally, the strain effect in InGaN multi‐quantum wells (MQWs) from single p‐type AlGaN EBL can be reduced by forming the AlGaN/GaN super lattice structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of optical phonons and electronic properties of group III‐V nitride multi quantum wells by using far infrared magnetoplasmon spectroscopy
Authors: Farjami Shayesteh S. , Rahmani A. , Parker T. J.
Published: May 2006

In this work, the behavior of optical phonons and magnetoplasmon‐ modes in the doped group III‐V Nitride semiconductor multi quantum wells are investigated in the presence of high magnetic fields parallel to the surface of the layers and perpendicular to the propagation direction by using p‐ and s‐polarized infrared magnetoplasmon reflectivity and employing an effective medium approach. Also, the modified random‐element isodisplacement model is employed to obtain the vibrational modes of GaNAs and AlGaN ternary alloy with zinc‐blend and wurzite structure. The effective carrier mass, the free carrier concentration and the mobility parameters can be quantified upon model analysis of the infrared p‐polarized magnetoplasma reflectivity and the infrared Voigt dielectric function. Theoretical results are compared and discussed with the existing far infrared and Raman scattering data. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of optical loss on blue‐violet laser diodes
Authors: Son J. K. , Hwang J. S. , Lee S. N. , Sakong T. , Paek H. , Chae S. , Kim H. K. , Nam O. , Kim J. Y. , Cho Y. H. , Park Y.
Published: May 2006

We measured optical loss of laser diodes by taking the intensity decay of edge emitting photoluminescence with respect to the distance from cleaved edges of wafers to the position where an excitation laser was focused. Measurements were performed on wafers with different thickness of InGaN p‐waveguide. We found that optical loss of wafers was determined by absorption of Mg doped GaN for narrow InGaN waveguide and by absorption of InGaN for thick InGaN waveguide. From experimental data and fittings, we obtained 40 cm–1 for InGaN absorption at 405 nm. Therefore, we conclude that the optical losses still remain even though the Mg‐doped GaN regions are far enough from QWs and that absorption loss of InGaN layers is relatively high comparing with undoped GaN. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
n‐type conductivity control of AlGaN with high Al mole fraction
Authors: Katsuno Takuya , Liu Yuhuai , Li Dabing , Miyake Hideto , Hiramatsu Kazumasa , Shibata Tomohiko , Tanaka Mitsuhiro
Published: May 2006

Silicon doped AlxGa1–xN with high Al mole fraction was grown using epitaxial AlN as a underlying layer by low‐pressure metalorganic vapor phase epitaxy. n‐type conductivity control of high quality Si‐doped AlxGa1–xN was achieved successfully. Structural, electrical and optical properties were investigated for various Al mole fractions, flow rates of silicon, and AlxGa1–xN thickness, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermalization and recombination in exponential band tail states
Authors: Niehus M. , Schwarz R.
Published: May 2006

We present an analytical model that combines the complementary experimental evidence of spatial dispersion (DAP recombination) and energetic dispersion (band tails). The model describes the competition between thermalization and recombination of excess carriers trapped in exponentially distributed (in energy), discrete localized (in space) states. We use the energy dependence of the relaxation rates to derive the energy and time dependence of sub gap photoluminescence. The model predicts that the yellow luminescence band (YLB) and blue luminescence band (BLB) commonly observed in GaN are not separate entities, but reflect the competition of thermalization and recombination. A distinct kink is observed in transient PL in the microsecond range, in the limiting cases of strong tailing and/or low temperatures, indicating the transition from thermalization‐limited to (radiative) recombination‐limited excess carrier relaxation. Both prediction are in line with experiment, and able to resolve interpretational difficulties. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropy of the Γ‐point effective mass and mobility in hexagonal InN
Authors: Hofmann T. , Chavdarov T. , Darakchieva V. , Lu H. , Schaff W. J. , Schubert M.
Published: May 2006

We determine the anisotropic electron effective mass and mobility parameters in wurtzite InN thin films with free electron concentration N from 1.8 × 1017 cm–3 to 9.5 × 1018 cm–3 using Infrared Magneto‐optic Generalized Ellipsometry. The room‐temperature measurements were carried out with magnetic fields up to 4.5 T. For the Γ‐point we estimate m *⊥ = 0.047m 0 and m *‖ = 0.039m 0 for polarization perpendicular and parallel to the c ‐axis, respectively. Scattering by impurities or ionized donors may explain the decrease of mobility for polarization parallel to the c ‐axis from 1600 cm2/(Vs) to 800 cm2/(Vs) with increase in N , where the perpendicular mobility is further decreased, likely caused by additional grain boundary scattering. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparing proportional hazards and accelerated failure time models: an application in influenza
Authors: Patel Katie , Kay Richard , Rowell Lucy
Published: May 2006

The proportional hazards (PH) model is routinely employed for the analysis of time‐to‐event data in medical research when it is required to assess the effect of an intervention in the presence of covariates. The assumption of PH required for the PH approach may not hold, especially in circumstances where the effect of the intervention is to delay or accelerate the onset of an event rather than to reduce or increase the overall proportion of subjects who observe the event through time. If the assumption of PH is violated, the results from a PH model will be difficult to generalize to situations where the length of follow‐up is different to that used in the analysis. It is also difficult to translate the results into the effect upon the expected median duration of illness for a patient in a clinical setting. The accelerated failure time (AFT) approach is an alternative strategy for the analysis of time‐to‐event data and can be suitable even when hazards are not proportional and this family of models contains a certain form of PH as a special case. The framework can allow for different forms of the hazard function and may provide a closer description of the data in certain circumstances. In addition, the results of the AFT model may be easier to interpret and more relevant to clinicians, as they can be directly translated into expected reduction or prolongation of the median time to event, unlike the hazard ratio. We recommend that consideration is given to an AFT modelling approach in the analysis of time‐to‐event data in medical research. Copyright © 2006 John Wiley & Sons, Ltd.
The contextual meaning of sustainable development: the case of the Dutch drinking water sector
Authors: Klostermann Judith E. M. , Cramer Jacqueline
Published: May 2006

The concept of sustainable development means different things to different people in different contexts, leading to ‘strong’ and ‘weak’ versions of sustainability. This article addresses the question of which meaning of sustainability is given by the Dutch drinking water sector and its main stakeholders. The ‘weak’, or human‐oriented, school was found at three of the four water companies studied. This is understandable, because water companies have a human‐oriented task: to provide the public with drinking water. The ‘strong’ version of sustainability was found within several governmental bodies. Their view of ‘staying within the natural water system’ was unacceptable for most other societal actors. A third form of sustainability was developed by the fourth drinking water company studied. It bridges the human and nature interests in a step by step dialogue. This way of looking at sustainable development may be an interesting perspective in which humans start seeing themselves as an integral part of nature again, instead of as being outside and above nature. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
A data envelopment analysis approach to the assessment of natural parks' economic efficiency and sustainability. The case of Italian national parks
Authors: Bosetti Valentina , Locatelli Gianni
Published: May 2006

Wilderness protection is a growing necessity for modern societies, and this is particularly true for areas where population density is extremely high, for example Europe. Conservation, however, implies very high opportunity costs. It is thus crucial to create incentives for efficient management practices, to promote benchmarking and to improve conservation management. In the present paper we propose a methodology based on data envelopment analysis, DEA, a non‐parametric benchmarking technique specifically developed to assess the relative efficiency of decision‐making units. In particular, the objective of the discussed methodology is to assess the relative efficiency of the management units of the protected area and to indicate how it could be improved, by providing a set of guidelines. The main advantage of this methodology is that it allows us to assess the efficiency of natural park management not only internally (comparing the performance of the park with itself over time) but also by external benchmarking, thus providing new and different perspectives on potential improvements. Although the proposed methodology is fairly general, we have applied it to the context of Italian national parks in order to produce a representative case study. Specifically, the choice of adequate cost and benefit indicators is a very important and delicate phase of any benchmark analysis. For this purpose, a questionnaire was used to investigate the opinions of Italian national park managers and stakeholders and to define the relevant indicators for the analysis. Finally, relevant policy implications for the case study are given. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Strategic partnerships between MNEs and civil society: the post‐WSSD perspectives
Authors: Eweje Gabriel
Published: May 2006

This paper addresses the question of how business organizations, civil society organizations and government agencies can engage one another for ‘boundary‐spanning’ dialogue and develop mutually beneficial ‘working partnerships’ in resolving the challenges of sustainable development. Over the past decade the concept of sustainable development has expanded to include the simultaneous consideration of economic growth, environmental protection and social equity in business and decision making. An increasing number of businesses have responded by engaging in corporate citizenship programmes to promote sustainable development. Strategic partnerships between civil society organizations and businesses are widely promoted as important new strategies, which will bring significant sustainable development benefits especially to developing countries. This interaction arises from an understanding of the need for comprehensive and integrated approaches to business, environmental and social issues that involve increasingly broader participation. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Endovascular management of the carotid blowout syndrome
Authors: Broomfield S J , Bruce I A , Luff D A , Birzgalis A R , Ashleigh R J
Published: May 2006

Bleeding from the carotid artery or its branches (‘carotid blowout’) is a well recognized complication following treatment or recurrence of head and neck cancer. The traditional surgical treatment for carotid blowout is often technically difficult and is associated with an unacceptably high morbidity and mortality. The majority of such patients are currently treated conservatively with end of life supportive measures.

We report the case of a young patient with recurrent supraglottic carcinoma complicated by carotid blowout on two separate occasions over a five month period, which was successfully treated endovascularly under local anaesthetic, without neurological sequelae. With the continuing development of interventional radiology, endovascular techniques are now emerging as a viable, low morbidity treatment option in selected patients.
Isolated hemifacial hypertrophy: a case with upper airway obstruction and sensorineural hearing loss
Authors: Oktay M F , Topcu I , McKinney A , Turunz V , Aras O
Published: May 2006

Hemifacial hypertrophy is an uncommon developmental disorder characterized by facial asymmetry that involves abnormal bone development and facial enlargement. Many cases of hemihypertrophy have been reported since the first case was reported by Wagner in 1839. We identified a child diagnosed with hemifacial hypertrophy and sensorineural hearing loss who presented with upper airway obstruction and cyanosis. We discuss treatment selection and review the associated head and neck symptoms.
The impact of methicillin-resistant Staphylococcus aureus on ENT practice
Authors: Nixon I J , Bingham B J G
Published: May 2006

Antibiotic-resistant bacteria are increasingly common and present a major problem for the modern day ENT surgeon. This article reviews the development of methicillin resistance in Staphylococcus aureus and how it has come to affect ENT practice. We look at the evidence behind measures taken to help deal with methicillin-resistant Staphylococcus aureus (MRSA) and to prevent its spread. We go on to suggest a departmental guideline for infection control, which we hope can be implemented to help deal with the problems created by MRSA.
Surgical closure of the larynx for intractable aspiration, using double hinged flaps of the vocal folds and false vocal folds
Authors: Sato K , Nakashima T
Published: May 2006

We report a new surgical procedure to treat intractable aspiration: closure of the larynx, using double hinged flaps of the vocal folds and false vocal folds.

The anterosuperior portion of the thyroid cartilage is ablated. A small horizontal incision is made just above the anterior commissure and is continued posteriorly along the laryngeal ventricle; these incisions are continued across the posterior wall of the glottis. Incisions are made into the bilateral vocal folds and false vocal folds in order to create the hinged flaps. The glottis and the supraglottis are closed by approximating the bilateral vocal folds and false vocal folds hinged flaps. Superiorly or inferiorly based sternohyoid muscle pedicles are then inserted into the dead space between the approximated bilateral vocal folds and false vocal folds hinged flaps. The removed lamina of the thyroid cartilage is obliterated between both sternohyoid muscle flaps to enforce the closure of the larynx.
Unusual middle-ear mischief: trans-tympanic trauma from a hair grip resulting in ossicular, facial nerve and oval window disruption
Authors: Snelling J D , Bennett A , Wilson P , Wickstead M
Published: May 2006

A case of piercing of the tympanic membrane, resulting in unusual consequences, is described. This is the first reported case of the long process of a dislocated incus resulting in trauma to the horizontal portion of a dehiscent facial nerve. Simultaneous depression of the stapes footplate resulted in a perilymph leak, but with delayed presentation.
Do mobile 'phones have a detrimental impact on auditory function?
Authors: Khalil S , Nunez D A
Published: May 2006

Mobile telephones are now an integral part of modern telecommunications. The widespread use of mobile telephones has given rise to concern about the potential influences of electromagnetic fields (EMFs) on human health. The effects of EMFs on human beings are under investigation. Anatomically, the ear is in close proximity to the mobile telephone during use. The effect of mobile phones on auditory function has rarely been studied. The aim of this review is to determine if there is evidence that mobile phones have a detrimental effect on auditory function.
Surgical management of trigeminal neuromas: a report of eight cases
Authors: Moffat D , De R , Hardy D , Moumoulidis I
Published: May 2006

Objective: Trigeminal neuromas are rare tumours that may involve any part of the Vth nerve complex, including extracranial peripheral divisions of the nerve. A series of eight patients with intracranial trigeminal neuromas who underwent surgical management are presented.

Methods: The hospital records and radiological images were reviewed with regard to clinical presentation, surgical approach, operative findings, peri-operative morbidity and neurological outcome, and percentage of tumour recurrence.

Results: The principal presenting symptoms were those of involvement of the trigeminal nerve with sensory impairment in one or more of the three divisions. Tumour location was the prime determinant of surgical approach. Lateral skull base approaches were used as they are considered to be superior for identifying tumour origin, extension, and relationship to surrounding structures. Total excision of the tumour was carried out in three of the eight patients. In the remaining five patients some tumour was left purposely in order to minimize neurological deficit and optimize post-operative quality of life. There was no peri-operative mortality or major morbidity in our series. Five patients experienced symptomatic tumour recurrence and revision surgery was performed.

Conclusion: Management of trigeminal neuromas is complex and requires a multidisciplinary approach. Pre-operative surgical planning allows tumour removal with preservation of important neural structures in the majority of cases. For large tumours occupying both the middle and posterior cranial fossae, the retrosigmoid/retrolabyrinthine/middle cranial fossa approach provides good exposure and results in minimal brain retraction. A Fisch type C approach is necessary for the largest tumours. Long-term follow up with interval imaging is mandatory to exclude long-term tumour recurrence.
Petrous apex cholesterol granuloma: transsphenoid endoscopic approach
Authors: Presutti Livio , Villari Domenico , Marchioni Daniele
Published: May 2006

The transsphenoid approach to the petrous apex, a surgical procedure described for the first time by Montgomery in 1977, is a rarely performed approach for the drainage and ventilation of cholesterol granuloma. We consider this approach to be the technique of choice when the cholesterol granuloma is located in the medial section of the petrous apex abutting and/or prolapsing into the posterior wall of the sphenoid sinus. The transsphenoid approach, unlike other lateral approaches to the petrous apex, is highly conservative and spares cochlear and vestibular function; moreover, it allows simple and adequate post-operative endoscopic follow up as an out-patient, with easier treatment in the case of recurrence.
Export Commodity and Regional Currency: The Role of Chinese Copper Coins in the Melaka Straits, Tenth to Fourteenth Centuries
Authors: Heng Derek Thiam Soon
Published: May 2006

In the Melaka Straits, Chinese copper cash has been recovered archaeologically, in varying quantities, from land settlement sites dated to between the tenth and fourteenth centuries. Despite their apparent importance, their role and function in a regional context is still largely unknown. This article seeks to reconstruct the usage of these coins in the Straits region through the integrative use of Chinese textual information and archaeological data.
Women, Westernization and the Origins of Modern Vietnamese Theatre
Authors: Wilcox Wynn
Published: May 2006

Modern spoken theatre emerged in Vietnam in the context of the intellectual and social upheaval of the 1920s and 1930s. Plays in this period focused on the status of women, the effects of Westernization and the emergence of Vietnamese nationalism. In Nam Xu′o′ng's 1930 play Ông Tây An-nam, women became conduits through which men expressed their Westernized or nationalist identities.
Indonesia 1939–1942: Prelude to the Japanese Occupation
Authors: Sato Shigeru
Published: May 2006

In the conventional historiography of Indonesia, the Second World War is equated with the Japanese occupation, and 1942 is a year of sudden change. This article argues that there was a prelude to these conditions. Changes in the global economic structure due to the Second World War, and countermeasures by the state authorities, began well before the Japanese invasion. The fundamental problem was the gradually deepening economic isolation that necessitated state intervention.
The Position of Islam in the Constitution of Malaysia
Authors: Fernando Joseph M.
Published: May 2006

The Federal Constitution of Malaysia states that Islam is the religion of the Federation. This provision in Article 3(1), inserted in 1957 when the independence constitution was framed, has drawn considerable scholarly attention in recent years. Most of the studies, however, have not been able to consult the primary constitutional documents. Invariably, many have given varied and ambiguous interpretations of the provision. This article examines the primary constitutional documents and constitutional debates between 1956 and 1957 to trace the origin of Article 3(1) and to determine the intentions of the framers in inserting this provision in the constitution.
The Domination of a Fussy Strongman in Provincial Thailand: The Case of Banharn Silpa-archa in Suphanburi
Authors: Nishizaki Yoshinori
Published: May 2006

Several scholars portray Thai provincial strongmen as having character traits associated with nakleng – ‘tough guys’ – who are violent and ruthless toward enemies, but generous and compassionate toward supporters. Banharn Silpa-archa, the strongman of Suphanburi province, does not fit the description however. His personality is reflected in the way he meticulously – fussily – monitors all local development projects. This surveillance pushes otherwise lazy and inefficient local civil servants to be more diligent in their work. Banharn's domination rests on Suphanburians' appreciation of his non-nakleng-type leadership.
Reflections on the ‘Disappearing Sakai’: A Tribal Minority in Southern Thailand
Authors: Hamilton Annette
Published: May 2006

The minority tribal groups in the border zones of Southern Thailand (the ‘Sakai’) are often described as ‘disappearing’ demographically while the inability to ‘know’ them at first hand by successive interested parties (the colonial explorer, the naturalist, the government official) has been attributed to their ability to disappear into the jungle, seemingly without a trace. This paper discusses the way the ‘Sakai’ have faded in and out of ethnology and Thai public consciousness, due in part to their own survival imperatives, and in part to the character of Thai state and society.
‘Died in the Service of Portugal’: Legitimacy of Authority and Dynamics of Group Identity among the Atsabe Kemak in East Timor
Authors: Molnar Andrea K.
Published: May 2006

The paper examines the metaphors and dynamics of Atsabe Kemak group identity construction, with a strong emphasis on local cultural ‘remembering’ of Atsabe history vis-à-vis relations of power. The analysis utilizes the analytical frameworks of Foucault's notion of discourse and Bourdieu's concept of habitus. The secondary burial of a former chieftain highlights the dynamics of Atsabe Kemak responses to new nation-building processes and to international influences that have appeared during the United Nations' transitional administration.
Local Integration and Coastal Connections in Interior Kalimantan: The Case of the Nalin Taun Ritual among the Bentian
Authors: Sillander Kenneth
Published: May 2006

Through the analysis of a Bentian Dayak ritual – the nalin taun – this article discusses how this ritual went through a change that reflected a transformation of the social organisation of the Bentian in the late nineteenth and early twentieth centuries, thus revealing the complex and important interaction between Malays and Dayaks in eastern Borneo. The conclusions overturn stereotypes of Dayak isolation and critique ahistorical analyses of cultural traditions in Southeast Asia.
The phonetic motivation for phonological stop assibilation
Authors: Hall T. A. , Hamann Silke , Zygis Marzena
Published: May 2006

This article examines the motivation for phonological stop assibilations, e.g. /t/ is realized as [ts], [s] or [t∫] before /i/, from the phonetic perspective. Hall & Hamann (2006) posit the following two implications: (a) Assibilation cannot be triggered by /i/ unless it is also triggered by by /j/, and (b) voiced stops cannot undergo assibilations unless voiceless ones do. In the following study we present the results of two acoustic experiments with native speakers of German and Polish which support implications (a) and (b). In our experiments we measured the friction phase after the /t d/ release before the onset of the following high front vocoid for four speakers of German and Polish. We found that the friction phase of /tj/ was significantly longer than that of /ti/, and that the friction phase of /t/ in the assibilation context is significantly longer than that of /d/. Furthermore, we unexpectedly found that the friction phase of /tj/ is significantly longer than that of /di/. An additional finding not related to the topic of the present study was that the Polish voiceless stops of the four speakers tested showed aspiration, in contrast to phonetic descriptions of these sounds as unaspirated.
Analysis of theTrypanosoma cruzicyclophilin gene family and identification of Cyclosporin A binding proteins
Authors: POTENZA M. , GALAT A. , MINNING T. A. , RUIZ A. M. , DURAN R. , TARLETON R. L. , MARÍN M. , FICHERA L. E. , BÚA J.
Published: May 2006

TheTrypanosoma cruzicyclophilin gene family comprises 15 paralogues whose nominal masses vary from 19 to 110 kDa, namelyTcCyP19,TcCyP20,TcCyP21,TcCyP22,TcCyP24,TcCyP25,TcCyP26,TcCyP28,TcCyP29,TcCyP30,TcCyP34,TcCyP35,TcCyP40,TcCyP42 andTcCyP110. Under the conditions used, only some of theT. cruzicyclophilin paralogue products could be isolated by affinity chromatography. The 15 paralogues were aligned with 495 cyclophilins from diverse organisms. Analyses of clusters formed by theT. cruzicyclophilins with others encoded in various genomes revealed that 8 of them (TcCyP19,TcCyP21,TcCyP22,TcCyP24,TcCyP35,TcCyP40,TcCyP42 andTcCyP110) have orthologues in many different genomes whereas the other 7 display less-defined patterns of their sequence attributes and their classification to a specific group of cyclophilin's orthologues remains uncertain. Seven epimastigote cDNA clones encoding cyclophilin isoforms were further studied. These genes were found dispersed throughout the genome of the parasite. Amastigote and trypomastigote mRNAs encoding these 7 genes were also detected. We isolated 4 cyclosporin A-binding proteins inT. cruziepimastigote extracts, which were identified by mass spectrometry asTcCyP19,TcCyP22,TcCyP28 andTcCyP40. Cyclosporin A-binding to these cyclophilins might be of importance to the mechanism of action of Cyclosporin A and its non-immunosuppressive analogues, whose trypanocidal effects were previously reported, and therefore, of potential interest in the chemotherapy of Chagas' disease.
The virus infecting the parasitoidLeptopilina boulardiexerts a specific action on superparasitism behaviour
Authors: VARALDI J. , PETIT S. , BOULÉTREAU M. , FLEURY F.
Published: May 2006

Parasites often induce behavioural changes in their host. However, it is not necessarily easy to determine whether these changes are representative of an adaptation of the parasite (parasite manipulation), an adaptive response of the host or a side-effect of infection. In a solitary parasitoid ofDrosophilalarvae (Leptopilina boulardi), viral particles (LbFV) modify the host acceptance behaviour of infected females by increasing their tendency to superparasitize. This behavioural alteration allows for the horizontal transmission of the virus within superparasitizedDrosophilalarvae. To add support for or against the ‘manipulation hypothesis’, we investigated whether other behavioural components of the parasitoid are affected by viral infection, and whether other forms of horizontal transmission exist. Neither the ability of females to locate host kairomones nor their daily rhythm of locomotor activity was affected by viral infection. However, infected females showed a lower rate of locomotor activity, suggesting a physiological cost of infection. The searching paths of females were also unaffected. Males from infected and uninfected lines showed the same ability to locate females'sexual pheromones. Moreover, alternative modes of horizontal transmission (through food consumption and/or contact with the sameDrosophilalarvae) did not lead to viral contamination of the parasitoid. The overall specificity of behavioural alteration and of viral horizontal transmission is consistent with the hypothesis that the virus manipulates the behaviour of the parasitoid.
Theory of Mind (ToM) and counterfactuality deficits in schizophrenia: misperception or misinterpretation?
Authors: LEITMAN DAVID I. , ZIWICH RACHEL , PASTERNAK ROEY , JAVITT DANIEL C.
Published: May 2006

Background. Theory of Mind (ToM) refers to the ability to infer another person's mental state based upon interactional information. ToM deficits have been suggested to underlie crucial aspects of social interaction failure in disorders such as autism and schizophrenia, although the development of paradigms for demonstrating such deficits remains an ongoing area of research. Recent studies have explored the use of sarcasm perception, in which subjects must infer an individual's sincerity or lack thereof, as a ‘real-life’ index of ToM ability, and as an index of functioning of specific right hemispheric structures. Sarcastic detection ability has not previously been studied in schizophrenia, although patients have been shown to have deficits in ability to decode emotional information from speech (‘affective prosody’).

Method. Twenty-two schizophrenia patients and 17 control subjects were tested on their ability to detect sarcasm from spoken speech as well as measures of affective prosody and basic pitch perception.

Results. Despite normal overall intelligence, patients performed substantially worse than controls in ability to detect sarcasm (d=2·2), showing both decreased sensitivity (A′) in detection of sincerity versus sarcasm and an increased bias (B″) toward sincerity. Correlations across groups revealed significant relationships between impairments in sarcasm recognition, affective prosody and basic pitch perception.

Conclusions. These findings demonstrate substantial deficits in ability to infer an internal subjective state based upon vocal modulation among subjects with schizophrenia. Deficits were related to, but were significantly more severe than, more general forms of prosodic and sensorial misperception, and are consistent with both right hemispheric and ‘bottom-up’ theories of the disorder.
A population-based family study of DSM-III generalized anxiety disorder
Authors: NEWMAN STEPHEN C. , BLAND ROGER C.
Published: May 2006

Background. A recent meta-analysis provides evidence that generalized anxiety disorder (GAD) is familial. However, two of the key studies relied on subjects who were self-selected or recruited from the clinic setting, thereby limiting generalizability.

Method. We conducted a family study of GAD in which probands and controls came from a community sample originally enrolled in a prevalence study in Edmonton, Canada. One hundred and sixty probands, 764 controls and 2386 first-degree relatives (FDRs) were interviewed using the Diagnostic Interview Schedule (DIS); lifetime diagnoses were made according to DSM-III criteria without exclusions. Logistic regression analysis was performed with GAD (in a proband) as the ‘exposure’, and GAD in an FDR as the ‘outcome’. Several analytic strategies were used to control for potential confounding by major depressive disorder (MDD) and several anxiety disorders (panic disorder, phobic disorders, obsessive–compulsive disorder, and post-traumatic stress disorder).

Results. The odds ratios for the association between GAD in a proband and GAD in an FDR were in the range 1·4–1·8 when the entire FDR sample was analysed, and in the range 2·1–2·8 when we restricted to FDRs who were children of probands and controls.

Conclusion. In the community setting, GAD exhibits mild to moderate familial aggregation.
The influence of emotions on inhibitory functioning in borderline personality disorder
Authors: DOMES GREGOR , WINTER BRITTA , SCHNELL KNUT , VOHS KNUT , FAST KRISTINA , HERPERTZ SABINE C.
Published: May 2006

Background. Borderline personality disorder (BPD) is characterized by an emotionally unstable and impulsive cognitive and behavioral style. Inhibitory dysfunction has been hypothesized as playing a crucial role in BPD psychopathology. This study aimed to systematically investigate differential inhibitory functions in patients with BPD as compared to healthy controls, and to investigate their expected impairment in the context of aversive emotions by comparing performances in neuropsychological tasks that present both neutral and emotional material.

Method. Unmedicated female patients with BPD (n=28) were compared with age-matched healthy female controls (n=30) in the following tasks: the emotional Stroop test (inhibition of interference), directed forgetting (intentional, resource-dependent inhibition), and an emotional variant of the negative priming task (automatic, resource-independent inhibition).

Results. In comparison with the controls, the BPD patients showed reduced inhibition of negative material in the directed forgetting task and in the negative priming task. No effect was found in the emotional Stroop test. Significant correlations with current affect as well as trait anxiety and anger (but not impulsiveness) were found in the BPD group specifically for negative stimuli, while no such correlations were found in the control group. In addition to inhibitory deficiencies, BPD patients had difficulties remembering positive words in the directed forgetting task.

Conclusions. Our data suggest that individuals with BPD have difficulties in actively suppressing irrelevant information when it is of an aversive nature. Inhibitory dysfunction appears to be closely related to state and trait variables of unstable affect, but not to self-reported impulsiveness.
Behavioural and neuropsychological correlates of frontal lobe features in dementia
Authors: ENGELBORGHS SEBASTIAAN , MAERTENS KAREN , MARIËN PETER , VLOEBERGHS ELLEN , SOMERS NORE , NAGELS GUY , DE DEYN PETER P.
Published: May 2006

Background. In order to characterize frontal lobe features and their behavioural and cognitive correlates across diagnostic categories, we performed a cross-sectional analysis of behavioural and neuropsychological data from a large, prospective Belgian study on behavioural and psychological signs and symptoms of dementia (BPSD).

Method. Patients with probable Alzheimer's disease (AD) (n=170), frontotemporal dementia (FTD) (n=28), mixed dementia (MXD) (n=29) and dementia with Lewy bodies (DLB) (n=21) were included and underwent neuropsychological and behavioural assessment by means of a battery of tests and scales. Frontal lobe symptoms were quantified by means of the Middelheim Frontality Score (MFS).

Results. In AD (and to a lesser extent in MXD), MFS total scores were negatively correlated with scores on MMSE (Spearman: r=−0·36, p<0·001) and a Verbal Fluency Task (r=−0·38, p<0·001) and were associated with increased severity and frequency of psychosis (r=0·24, p<0·01), activity disturbances (r=0·44, p<0·001) and aggressiveness (r=0·43, p<0·001). In DLB, MFS total scores were negatively correlated with MMSE scores (r=−0·50, p=0·020). No associations were found in FTD patients.

Conclusions. A cross-sectional analysis of frontal lobe features, behavioural characteristics and neuropsychological data demonstrated that, in AD (and to a lesser extent in MXD) patients, frontal lobe symptoms were associated with more pronounced cognitive deficits (of frontal origin), with increased severity and frequency of agitated and aggressive behaviour, and with increased severity of psychosis and depressive symptoms. Given the small sample sizes of the DLB and FTD patient groups, negative findings in these patient groups should be interpreted cautiously.