bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal uptake in lolium perenne established on spent mushroom compost amended lead‐zinc tailings
Authors: Jordan S. N. , Mullen G. J. , Courtney R. G.
Published: April 2009

A greenhouse trial was performed to contrast the growth and metal accumulation in Lolium perenne established on pyritic tailings amended with varying applications of spent mushroom compost (SMC). The lead‐zinc tailings were retrieved from a moderately vegetated land impoundment facility located at Gortmore, Silvermines, Co. Tipperary (Ireland) and SMC was incorporated at application rates of 0, 50, 100, 200 and 400 t ha−1. The grass species Lolium perenne was sown at an application rate of 200 kg ha−1 and the subsequent biomass determined after 42 and 84 days. For the most part, metal concentrations in Lolium perenne showed a significant linear response (p < 0·05) to SMC application and generally decreased favourably with increasing SMC application (p < 0·05). This phenomenon may be attributed to the vast biosorption capacity of SMC owing to the presence of phenolic, carboxyl and phenolic functional groups, the development of stable metal chelates by the organic matter present in SMC and/or by the biosorbing of toxic metals by fungal mycelium, however this reduction in metal uptake by Lolium perenne is most likely due to greater plant dry weight caused by the increasing SMC applications. In spite of this, Lolium perenne suffered severe toxicity resulting from the inherently high concentrations of total zinc (1443–5920 mg kg−1), lead (33–478 mg kg−1) and cadmium (1·4–49 mg kg−1) accumulated within the plant 84 days after seeding, the grass had adversely withered irrespective of SMC application. Therefore, a barrier break must be introduced in the tailings facility to prevent the uptake and accumulation of these lethal metal concentrations by plants. Only then should SMC and other suitable soil forming materials be utilized as growing media, as the incorporation of an organic amendment followed by direct seeding of a grass species is not economically or environmentally viable for permanent re‐vegetation of the Gortmore tailings management facility (TMF). Copyright © 2009 John Wiley & Sons, Ltd.
Soil conservation beneath grass cover in hillside vineyards under Mediterranean Climatic conditions (Madrid, Spain)
Authors: Marques M. J. , García‐Muñoz S. , Muñoz‐Organero G. , Bienes R.
Published: April 2009

The use of plant cover for soil protection in Mediterranean hillside vineyards may jeopardize the viability of crops due to the scarcity of water under semiarid conditions. Erosion control, soil characteristics and vineyard production were evaluated using three different treatments: (i) traditional tillage as the control group, (ii) soil covered by Brachypodium distachyon and (iii) soil covered by Secale cereale. Such plant cover for soil protection among woody crops is not frequent under semiarid conditions.

Sediment yield and runoff were collected from nine (3 treatments × 3 replications) plots of 2 m2. Soil moisture, organic carbon content and aggregate stability were measured for one year. Simulated rainfall on plots was used as a source of complementary data.

A reduction of 50% in the production of the vineyard was noticed in the Brachypodium‐treatment, probably due to the lower degree of soil moisture at 35 cm depth. Nevertheless, there was efficient erosion control and the soil's organic carbon content increased. The Secale‐treatment produced more runoff than tillage treatment. Traditional tilling produced the greatest yield, though it is considered unsustainable in the long term for hillside vineyards, as it lost 1059 g m−2y−1, compared to 62 and 70 g m−2y−1 lost in soil covered with Secale and Brachypodium, respectively. A high variability was found in the runoff coefficient, which was usually less than 1% under moderate rainfall, although it reached 45% under extreme events.

The blind tasting of wine showed a slight preference for wine produced on vines subject to the Secale treatment. Copyright © 2009 John Wiley & Sons, Ltd.
Is rainfall erosivity increasing in the Mediterranean Iberian Peninsula?
Authors: De Luis M. , González‐Hidalgo J. C. , Longares L. A.
Published: April 2009

The risk of erosion and desertification is one of the main environmental concerns in the Mediterranean Iberian Peninsula. Changes in precipitation are expected in Mediterranean areas because of climate change, but predictions are not certain. For this reason, dense precipitation databases are required to explore observed changes in the amount, concentration and variability of precipitation, to gain a clearer understanding of the dynamics involved in the main climatological agent of erosion. For this study, we took the recently developed MOPREDAMES dataset, which includes 1113 complete and homogeneous monthly rainfall series from the Mediterranean fringe of the Iberian Peninsula (IP) covering the period 1951–2000. These were used to calculate and analyse trends in Total Annual Precipitation (Pt), the Precipitation Concentration Index (PCI) and Modified Fourier Index (MFI). Our results show that, although there were decreases in annual rainfall, increases in the concentration of precipitation also predominated in the Mediterranean Iberian Peninsula during the period 1951–2000. However, spatial variability of these trends is high, and changes in rainfall erosivity exhibit a complex spatial pattern. Thus, decreases in rainfall erosivity are detected under semiarid conditions (Central Ebro basin and South East IP), while increases mainly occur in dry and sub‐humid areas. We present a detailed spatial description of the results and discuss their implication for the risk of erosion and desertification in different regions of the study area. Copyright © 2009 John Wiley & Sons, Ltd.
Global coffee market influence on land‐use and land‐cover change in the Western Ghats Of India
Authors: Ambinakudige S. , Choi J.
Published: April 2009

In this study, we used image‐processing techniques to examine the spatial pattern of land‐use and land‐cover (LULC) change that occurred in the coffee growing area in the Western Ghats of India during the international coffee crisis in the 1990s. The study also ascertains the driving forces of these changes using qualitative research methods that include archival studies and interviews of knowledgeable individuals. We analyzed Landsat Thematic Mapper (TM) for 1991 and Landsat ETM+ for 2002 to quantify LULC. Historical land‐use changes in different land ownership regimes were also analyzed. Global coffee market fluctuations were found to be the major cause of landscape change in the study region. When the global coffee prices increased, more forested areas were cleared for coffee cultivation. Failure of global coffee market forced farmers to convert land from subsistence farming (rice) to short‐period commercial crops like ginger. This also resulted in land degradation in rice paddies. For the farmers in the Western Ghats, LULC decisions are one of the methods used to cope with the vulnerability created due to the international coffee crisis. Copyright © 2009 John Wiley & Sons, Ltd.
Building talent: Developing effective leaders is as crucial as ever
Authors: Berke David , Kossler Michael E. , Wakefield Michael
Published: April 2009

Even in the midst of economic upheaval, some organizations recognize that making sure they have the right leadership talent in place will help them not only survive but thrive when the economy eventually rebounds. Developing leadership talent requires a systematic approach that begins with the organization's strategic goals and takes into account developmental needs at both the organizational and individual levels.
Fatal attraction: The dangers of leaders flocking together
Authors: Zahra Shaker A. , Eltantawy Reham A.
Published: April 2009

Despite efforts to increase diversity among companies' leaders, a phenomenon known as homophily—the tendency of individuals to like and associate with others who are similar to themselves—remains prevalent. Homophily can have serious implications for leaders and their organizations, jeopardizing morale and stifling innovation and strategic renewal.
Laser wakefield plasma accelerators
Authors: Krushelnick K. , Malka V.
Published: April 2009

Over the past several years there have been significant advances in research towards generating compact relativistic electron beams using high power short pulse laser produced plasmas (i.e., laser wakefield accelerators). In particular, an explosion of interest was generated in this field following the discovery in 2004 of a method to create such beams with low energy spread using a “plasma bubble” shaped wake. Recent work has increased the energy of these beams to the GeV range by extending the acceleration distance from a few millimetres to several centimeters. From both experimental and theoretical work, a more complete understanding of this “plasma bubble” regime for electron acceleration has also been obtained, enabling a significant improvement in the output electron beam quality and stability. There is ongoing work to further improve the parameters and stability of these beams with the goal of constructing “table‐top” 4th generation sources of coherent x‐ray radiation.
Boundary value problems with eigenvalue depending boundary conditions
Authors: Behrndt Jussi
Published: April 2009

We investigate some classes of eigenvalue dependent boundary value problems of the formequation imagewhereA⊂A+is a symmetric operator or relation in a Krein spaceK,τis a matrix function and Γ0, Γ1are abstract boundary mappings. It is assumed thatAadmits a self‐adjoint extension inKwhich locally has the same spectral properties as a definitizable relation, and thatτis a matrix function which locally can be represented with the resolvent of a self‐adjoint definitizable relation. The strict part ofτis realized as the Weyl function of a symmetric operatorTin a Krein spaceH, a self‐adjoint extensionÃofA×TinK×Hwith the property that the compressed resolventPK(Ã–λ)–1|Kkyields the unique solution of the boundary value problem is constructed, and the local spectral properties of this so‐called linearizationÃare studied. The general results are applied to indefinite Sturm–Liouville operators with eigenvalue dependent boundary conditions (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lp(ℝn) boundedness for higher commutators of singular integrals with rough kernels belonging to certain block spaces
Authors: Hou Yanyan , Tang Lin
Published: April 2009

In this paper, we prove theLp(ℝn) boundedness for higher commutators of singular integrals with rough kernels belonging to certain block spaces provided that 1 <p< ∞ (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Corings over rings with local units
Authors: Kaoutit L. El
Published: April 2009

We show that the bicategory whose 0‐cells are corings over rings with local units is bi‐equivalent to the bicategory of comonads in (right) unital modules whose underlying functors are right exact and preserve direct sums. A base ring extension of a coring by an adjunction is introduced as well (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Estimates of n ‐widths of Besov classes on two‐point homogeneous manifolds
Authors: Kushpel A. K. , Levesley J. , Tozoni S. A.
Published: April 2009

Estimates of Kolmogorov and linear n ‐widths of Besov classes on compact globally symmetric spaces of rank 1 (i.e., on Sd, Pd (ℝ), Pd (ℂ), Pd (ℍ), P16(Cay)) are established. It is shown that these estimates have sharp orders in different important cases. A new characterisation of Besov spaces is also given (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Orbits of Cesàro type operators
Authors: León–Saavedra F. , Piqueras–Lerena A. , Seoane–Sepúlveda J. B.
Published: April 2009

A bounded linear operator T on a Banach space X is called hypercyclic if there exists a vector x ∈ X such that its orbit, {Tnx }, is dense in X. In this paper we show hypercyclic properties of the orbits of the Cesàro operator defined on different spaces. For instance, we show that the Cesàro operator defined on Lp [0, 1] (1 < p < ∞) is hypercyclic. Moreover, it is chaotic and it has supercyclic subspaces. On the other hand, the Cesàro operator defined on other spaces of functions behave differently. Motivated by this, we study weighted Cesàro operators and different degrees of hypercyclicity are obtained. The proofs are based on the classical Müntz–Szász theorem. We also propose problems and give new directions (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identifying the best companies for leaders: does it lead to higher returns?
Authors: Filbeck Greg , Gorman Raymond F. , Zhao Xin
Published: April 2009

Since 2002, Chief Executive magazine, in conjunction with the Hay Group, has published a list of the Top 20 Companies for Leaders. In this paper, we examine the performance of those companies listed as being the best for leaders. We examine the announcement impact on share price associated with the press releases for firms included in the list and holding period returns between subsequent survey releases. While we generally do not find a significant difference in the performance of the Best Leader sample compared with either the market or the matched sample, we do find that the Best Leader sample outperforms other benchmarks on a raw and risk‐adjusted basis during times of high market volatility. Copyright © 2009 John Wiley & Sons, Ltd.
DFT‐GIAO 1H and 13C NMR prediction of chemical shifts for the configurational assignment of 6β‐hydroxyhyoscyamine diastereoisomers
Authors: Muñoz Marcelo A. , Joseph‐Nathan Pedro
Published: April 2009

1H and 13C NMR chemical shift calculations using the density functional theory–gauge including/invariant atomic orbitals (DFT–GIAO) approximation at the B3LYP/6‐311G++(d,p) level of theory have been used to assign both natural diastereoisomers of 6β‐hydroxyhyoscyamine. The theoretical chemical shifts of the 1H and 13C atoms in both isomers were calculated using a previously determined conformational distribution, and the theoretical and experimental values were cross‐compared. For protons, the obtained average absolute differences and root mean square (rms) errors for each comparison showed that the experimental chemical shifts of dextrorotatory and levorotatory 6β‐hydroxyhyoscyamines correlated well with the theoretical values calculated for the (3R,6R,2′S) and (3S,6S,2′S) configurations, respectively, whereas for 13C atoms the calculations were unable to differentiate between isomers. The nature of the relatively large chemical shift differences observed in nuclei that share similar chemical environments between isomers was asserted from the same calculations. It is shown that the anisotropic effect of the phenyl group in the tropic ester moiety, positioned under the tropane ring, has a larger shielding effect over one ring side than over the other one. Copyright © 2009 John Wiley & Sons, Ltd.
Danon disease: Further clinical and molecular heterogeneity
Authors: Sabourdy Frédérique , Michelakakis Helen , Anastasakis Aris , Garcia Virginie , Mavridou Irene , Nieto Michèle , Pons Marie‐Claude , Skiadas Constantinos , Moraitou Marina , Manta Panagiota , Elleder Milan , Levade Thierry
Published: April 2009

Two families of Greek patients with subclinical to severe cardiomyopathy are presented. The diagnosis of Danon disease was supported by a total lack of LAMP2 immunostaining in cultured skin fibroblasts and muscle biopsies. The LAMP2 mutation carried by one patient (c.928G>A) has already been reported but with different symptoms. The second patient had a novel point deletion. This has not been described previously, but it could be detected easily by restriction analysis. This mutation was also found in the patient's brother, and it was associated with severe cardiomyopathy leading to heart failure. Surprisingly, the proband also had partial reduction of α‐galactosidase A activity, despite the absence of characteristic clinical features of Fabry disease. A substitution in the GLA gene (c.937G>T) was found, and its involvement in the cardiac disease is discussed. Muscle Nerve, 2009
Myasthenia gravis associated with etanercept therapy
Authors: Fee Dominic B. , Kasarskis Edward J.
Published: April 2009

Etanercept is an antagonist of tumor necrosis factor alpha that was developed to treat rheumatoid arthritis. In this report we present a patient who developed myasthenia gravis while taking etanercept and had resolution of symptoms after stopping it. This is the first report of this potential side effect and is of additional interest, because etanercept has been proposed as a treatment for myasthenia gravis. Muscle Nerve, 2009
A large‐scale linear programming model for finding optimal container inspection strategies
Authors: Boros E. , Fedzhora L. , Kantor P. B. , Saeger K. , Stroud P.
Published: April 2009

Cargo ships arriving at US ports are inspected for unauthorized materials. Because opening and manually inspecting every container is costly and time‐consuming, tests are applied to decide whether a container should be opened. By utilizing a polyhedral description of decision trees, we develop a large‐scale linear programming model for sequential container inspection that determines an optimal inspection strategy under various limitations, improving on earlier approaches in several ways: (a) we consider mixed strategies and multiple thresholds for each sensor, which provide more effective inspection strategies; (b) our model can accommodate realistic limitations (budget, sensor capacity, time limits, etc.), as well as multiple container types; (c) our model is computationally more tractable allowing us to solve cases that were prohibitive in preceding models, and making it possible to analyze the potential impact of new sensor technologies. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009
Level set topology optimization of fluids in Stokes flow
Authors: Challis Vivien J. , Guest James K.
Published: April 2009

We propose the level set method of topology optimization as a viable, robust and efficient alternative to density‐based approaches in the setting of fluid flow. The proposed algorithm maintains the discrete nature of the optimization problem throughout the optimization process, leading to significant advantages over density‐based topology optimization algorithms. Specifically, the no‐slip boundary condition is implemented directly—this is accurate, removes the need for interpolation schemes and continuation methods, and gives significant computational savings by only requiring flow to be modeled in fluid regions. Topological sensitivity information is utilized to give a robust algorithm in two dimensions and familiar two‐dimensional power dissipation minimization problems are solved successfully. Computational efficiency of the algorithm is also clearly demonstrated on large‐scale three‐dimensional problems. Copyright © 2009 John Wiley & Sons, Ltd.
Displacement‐based finite elements with nodal integration for Reissner–Mindlin plates
Authors: Castellazzi G. , Krysl P.
Published: April 2009

An assumed‐strain finite element technique is presented for shear‐deformable (Reissner–Mindlin) plates. The weighted residual method (reminiscent of the strain–displacement functional) is used to enforce weakly the balance equation with the natural boundary condition and, separately, the kinematic equation (the strain–displacement relationship). The a priori satisfaction of the kinematic weighted residual serves as a condition from which strain–displacement operators are derived via nodal integration, for linear triangles, and quadrilaterals, and also for quadratic triangles. The degrees of freedom are only the primitive variables: transverse displacements and rotations at the nodes. A straightforward constraint count can partially explain the insensitivity of the resulting finite element models to locking in the thin‐plate limit. We also construct an energy‐based argument for the ability of the present formulation to converge to the correct deflections in the limit of the thickness approaching zero. Examples are used to illustrate the performance with particular attention to the sensitivity to element shape and shear locking. Copyright © 2009 John Wiley & Sons, Ltd.
The Well Woman Program: A community‐based randomized trial to prevent sexually transmitted infections in low‐income African American women
Authors: Marion Lucy N. , Finnegan Lorna , Campbell Richard T. , Szalacha Laura A.
Published: April 2009

In this sexually transmitted infection (STI) prevention study, we compared the efficacy of the Well Woman Program (WWP), a nurse practitioner‐directed, culturally specific, intensive intervention, to minimal intervention (MI), brief lecture, and referral to usual care, in a community‐based randomized controlled trial. African American women having past STIs and residing in high‐risk communities were randomly assigned to the two groups. STI outcome was measured at baseline and three later points. A random effects logistic longitudinal regression model showed that, at baseline, approximately 75% of participants tested positive for an STI, predominantly trichomoniasis. At month 15, the estimated probability of a WWP participant having an STI was 20% less than an MI participant. Better STI outcomes were due to the intensive individualized intervention. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32:274–285, 2009
Social welfare needs of residents in polluted areas: A case of Dioxin pollution in southern Taiwan
Authors: Lee Tsuey‐Ping , Yang Yungnane , Tung Chien‐Hung
Published: April 2009

This article defines the social welfare needs of residents living in a severely polluted community by examining a set of communities around the An‐shun plant in southern Taiwan that were polluted by dioxin. The study examines the inhabitants' economic status, the communities' manpower utilization, and the prevention of social contingencies and the provision of aftercare. A survey conducted between March–April 2008 revealed the need to reduce poverty in these highly polluted communities, to identify and maximize each community's human resources, to address illness, aging, pollution, and lack of professional skills, and to better inform residents about pollution so that they can understand how to protect themselves. The article concludes with suggested programs to meet the social welfare needs of residents in a highly polluted community. Copyright © 2009 John Wiley & Sons, Ltd.
Wilms tumor, AML and medulloblastoma in a child with cancer prone syndrome of total premature chromatid separation and Fanconi anemia
Authors: Sari Neriman , Akyuz Canan , Aktas Dilek , Gumruk Fatma , Orhan Diclehan , Alikasifoglu Mehmet , Aydin Burca , Alanay Yasemin , Buyukpamukcu Munevver
Published: April 2009

Wilms tumor (WT) is the most common primary renal tumor in childhood. The occurrence of WT in patients with growth retardation, mental retardation and central nervous system abnormalities in association with premature chromatid separation (PCS) and mosaic variegated aneuploidy has been previously described in only 10 patients. Here we report the very rare occurrence of WT with two other malignancies, acute myeloid leukemia and medulloblastoma in association with chromosomal instability. This is a novel presentation of Fanconi anemia with this cytogenetic abnormality. Pediatr Blood Cancer 2009;53:208–210. © 2009 Wiley‐Liss, Inc.
Death and serious illness following influenza vaccination: a multidisciplinary investigation
Authors: Rue‐Cover Alison , Iskander John , Lyn Shauna , Burwen Dale R. , Gargiullo Paul , Shadomy Sean , Blostein Joel , Bridges Carolyn B. , Haber Penina , Satzger R. Duane , Ball Robert , Seward Jane F.
Published: April 2009

Purpose

To evaluate a possible association between influenza vaccination and four deaths and four serious illnesses among 114 recent influenza vaccinees in a long‐term care facility (LTCF) and two deaths from a nearby physician's office. All had received vaccine from the same lot (Lot A).

Methods

Field investigation including (1) a retrospective cohort study among LTCF residents who received Lot A or other influenza vaccine, (2) review of medical records of cases of death or serious illness, (3) active surveillance of deaths among 1500 community based Lot A vaccinees and (4) laboratory testing of vaccine from available Lot A vials.

Results

Medical record reviews showed no common clinical syndrome or cause of death. Laboratory testing of Lot A samples revealed no evidence of tampering and no differences compared to an unrelated lot. The risk of death or hospitalization was not significantly different between persons who received Lot A versus a comparison lot, Lot B (incidence rate ratio (IRR) = 0.9, 95%CI = 0.3–3.3).

Conclusions

There was no clinical or biological evidence pointing to inherent vaccine safety issues, nor was there a detectable increased risk of death or hospitalization among persons vaccinated with Lot A. Lot specific clustering of adverse events (AEs) may reflect medical events causally unrelated to vaccination. Rapid investigations of potential AEs are important to ensure vaccine safety and to maintain public and healthcare provider confidence in vaccines. Copyright © 2009 John Wiley & Sons, Ltd.
Are herbicide‐resistant crops the answer to controlling Cuscuta?
Authors: Nadler‐Hassar Talia , Shaner Dale L , Nissen Scott , Westra Phill , Rubin Baruch
Published: April 2009

BACKGROUND: Herbicide‐resistant crop technology could provide new management strategies for the control of parasitic plants. Three herbicide‐resistant oilseed rape (Brassica napus L.) genotypes were used to examine the response of attached Cuscuta campestris Yuncker to glyphosate, imazamox and glufosinate. Cuscata campestris was allowed to establish on all oilseed rape genotypes before herbicides were applied.

RESULTS: Unattached seedlings of C. campestris, C. subinclusa Durand & Hilg. and C. gronovii Willd. were resistant to imazamox and glyphosate and sensitive to glufosinate, indicating that resistance initially discovered in C. campestris is universal to all Cuscuta species. Glufosinate applied to C. campestris attached to glufosinate‐resistant oilseed rape had little impact on the parasite, while imazamox completely inhibited C. campestris growth on the imidazolinone‐resistant host. The growth of C. campestris on glyphosate‐resistant host was initially inhibited by glyphosate, but the parasite recovered and resumed growth within 3–4 weeks.

CONCLUSION: The ability of C. campestris to recover was related to the quality of interaction between the host and parasite and to the resistance mechanism of the host. The parasite was less likely to recover when it had low compatibility with the host, indicating that parasite‐resistant crops coupled with herbicide resistance could be highly effective in controlling Cuscuta. Published 2009 by John Wiley & Sons, Ltd.
Dependence of N incorporation into (Ga)InAsN QDs on Ga content probed by rapid thermal annealing
Authors: Gargallo‐Caballero R. , Guzmán A. , Hopkinson M. , Ulloa J. M. , Hierro A. , Calleja E.
Published: April 2009

In this letter we demonstrate that the N incorporation into (Ga)InAsN quantum dots (QDs), grown on GaAs (100) by radio‐frequency (RF) plasma assisted molecular beam epitaxy (MBE), is enhanced as the Ga content increases up to 30% and decreases for Ga contents higher than 30%. Thus, this effect exhibits a maximum N incorporation with a Ga content of 30%. Two sets of (Ga)InAsN QDs samples have been grown under the same growth conditions but with different N contents in one of them and with different Ga concentration in the other set. Optical analysis using Photoluminescence (PL) measurements of the as‐grown and post growth rapid thermal annealed samples have been performed. The experimental results show a clear increase of the blueshift with the N concentration as occurred in dilute nitride quantum well (QW) structures. PL peak emission wavelength as high as 1.55 μm has been obtained from QDs capped with GaAs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performances comparison of Si and GaAs based resonant tunneling diodes
Authors: Buccafurri Emanuela , Clerc Raphael , Calmon Francis , Pala Marco , Poncet Alain , Ghibaudo Gerard
Published: April 2009

On the basis of an original, physically based analytical model, I‐V characteristic of the resonant tunneling diode structure (RTD) has been studied. Comparing AlAs/GaAs heterostructure RTD and Si‐based RTD of same dimensions, it turns out that the performances of GaAs devices are superior. However, similar performances can be achieved in the HfO2/Si RTD, by a strong reduction in barrier tunnel thickness and width well. In conclusion, an extreme shrinking of Hf02/Si structure dimensions can offer, in principle, RTD performances comparable to conventional AlAs/GaAs heterostructures. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of In‐doped ZnO films by metalorganic chemical vapor deposition on GaN(0001) templates
Authors: Ben‐Yaacov Tammy , Ive Tommy , Van de Walle Chris G. , Mishra Umesh K. , Speck James S. , Denbaars Steven P.
Published: April 2009

We investigated the properties of indium‐doped zinc oxide layers grown by metalorganic chemical vapor deposition on semi‐insulating GaN(0001) templates. Specular and transparent films with n‐type carrier concentrations up to 1.82 × 1019 cm–3, as determined by hall measurements, were grown. An undoped film grown under the same conditions had carrier concentration 5.4 × 1017 cm–3. An interesting trend was observed for carrier concentration dependence on In precursor flow. For low In flows, carrier concentration increased with TMI flow until a peak was reached for a TMI flow of 5 standard cubic centimetres per minute. Beyond this flow, carrier concentration decreased with increasing TMI flow rate. A sheet resistance as low as 185 ohm/sq was achieved for the indium‐doped films, which is a significant decrease from the undoped ZnO film which had a sheet resistance of 3100 ohm/sq. The results of this In doping study show that In is an effective dopant for controlling the n‐type conductivity of ZnO. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InGaAs channel MOSFET with self‐aligned source/drain MBE regrowth technology
Authors: Singisetti Uttam , Wistey Mark A. , Burek Gregory J. , Arkun Erdem , Baraskar Ashish K. , Sun Yanning , Kiewra Edward W. , Thibeault Brian J. , Gossard Arthur C. , Palmstrøm Chris J. , Rodwell Mark J. W.
Published: April 2009

InGaAs is a promising alternative channel material to Si for sub‐22 nm node technology because of its low electron effective mass (m*) hence high electron velocities. We report a gate‐first MOSFET process with self‐aligned source/drain formation using non‐selective MBE re‐growth, suitable for realizing high performance scaled III‐V MOSFETs. A W/Cr/SiO2 gate stack was defined on thin (4 nm/2.5 nm) InGaAs/InP channel by an alternating selective dry etch technique. A 5 nm Al2O3 layer was used as gate dielectric. An InAlAs bottom barrier provided vertical confinement of the channel. An in‐situ H cleaning of the wafer leaves an epi‐ready surface suitable for MBE or MOCVD regrowth.

Source/Drain region were defined by non‐selective MBE regrowth and in situ molybdenum contacts. First generation of devices fabricated using this process showed extremely low drive current of 2 μA/μm. The drive current was limited by an extremely high source resistance. A regrowth gap between source/drain and gate was the cause for high source resistance. The gap in the regrowth was because of low growth temperature (400 °C). A modified high temperature growth technique resolved the problem. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An over 100 W AlGaN/GaN enhancement‐mode HEMT power amplifier with piezoelectric‐induced cap structure
Authors: Ohki Toshihiro , Kikkawa Toshihide , Kanamura Masahito , Imanishi Kenji , Makiyama Kozo , Okamoto Naoya , Joshin Kazukiyo , Hara Naoki
Published: April 2009

A novel piezoelectric‐induced cap structure in an AlGaN/GaN high electron mobility transistor (HEMT) was developed for enhancement‐mode (E‐mode) operation with high maximum drain current density (Idmax), high breakdown voltage (BVgd) and small current collapse. Our developed cap structure consists of a thin GaN/AlN/ GaN triple‐layer, which reduces the sheet resistance (Rsh) due to conduction band bending. The threshold voltage (Vth) is +0.25 V with a high Idmax of 520 mA/mm, a high BVgd of 336 V and small current collapse by using the developed cap structure and a gate recess technique. The single‐chip AlGaN/GaN E‐mode HEMT amplifier achieved a high output power of 126 W at 2.5 GHz with improved distortion characteristics. This is the first report of an AlGaN/GaN E‐mode HEMT with an output power of over 100 W. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Advanced mHEMT MMICs for 220 GHz high‐resolution imaging systems
Authors: Chartier Sébastien , Tessmann Axel , Leuther Arnulf , Weber Rainer , Kallfass Ingmar , Schlechtweg Michael , Stanko Stephan , Essen Helmut , Ambacher Oliver
Published: April 2009

The development of advanced millimeter‐wave monolithic integrated circuits for application in active and passive high‐resolution imaging systems operating beyond 200 GHz is presented. A wideband 210 GHz Low Noise Amplifier has been successfully realized using one of our three metamorphic high electron mobility transistor (mHEMT) technologies in combination with grounded coplanar circuit topology (GCPW). Additionally, a 200 GHz voltage controlled oscillator (VCO) MMIC demonstrating good output power over a wide bandwidth was fabricated, using our 100 nm mHEMT technology. Finally, a high resolution 220 GHz radiometer was realized and shows very promising performance. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of band offsets and subband levels for a GaInP/AlGaInP quantum well by photoreflectance using a InGaP laser diode
Authors: Susaki Wataru , Kakuda Shinichi , Igawa Takahiro , Inada Takeshi , Tomioka Akihiro
Published: April 2009

The band offsets and subband levels in a double quantum well layer for a 660nm‐Ga0.4In0.6P/(Al0.5Ga0.5)0.5In0.5P quantum well laser are determined by photoreflectance using a 410 nm InGaN laser with current modulation at room temperature. The subband levels are analyzed by numerical calculation of the Schrödinger equation for the layer structure by varying the conduction band offset and compared with the measured photoreflectance spectra. The conduction band offset ratio is determined to be 0.5+0.03. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: Phys. Status Solidi C 6/4
Authors: Cho Yong‐Hoon , Kim Eun Kyu , Guest Editors
Published: April 2009

The Proceedings contained in this issue comprise all peer‐reviewed scientific papers presented at the 5th International Conference on Semiconductor Quantum Dots (QD 2008). The conference was held in Gyeongju, Korea, from 11 to 16 May 2008. Gyeongju, the capital of the Shilla Kingdom (BC 57–AD 935) for almost a thousand years, was designated as one of the World Cultural Heritage sites by UNESCO in 1995. QD 2008 was the fifth conference in a successful series, first held in Munich (2000) and then continued in Tokyo (2002), Banff (2004), and Chamonix‐Mont Blanc (2006). QD 2008 has enjoyed a record attendance by more than 300 participants from 27 countries. QD 2008 selected 304 papers for oral and poster presentation among contributed papers from all over the world. In these proceedings, we have included 87 papers which were presented at QD 2008. The present proceedings provide an excellent up‐to‐date overview over novel fabrication techniques of quantum dots, structural and electronic properties, optical and transport properties, magnetic and spin properties, as well as applications of quantum dots.

We would like to express our sincere thanks to all the participants and speakers, as well as all to the sponsors and public agencies for their help in making QD 2008 successful. We also express our gratitude to all organizing and program committee members for making a great contribution to the conference, as well as all publication committee members and the referees for their careful reading and scientific evaluation of the papers appearing in these proceedings. Finally, we also express our appreciation to Stefan Hildebrandt, Julia Hübner, and Irina Juschak for their great editorial assistance and to physica status solidi for the rapid publication of the proceedings (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inhibitory effect of total lignan from Fructus Arctii on aldose reductase
Authors: Xu Zhaohui , Yang Hongzhou , Zhou Mingmei , Feng Yi , Jia Wei
Published: April 2009

The potent inhibitory effect of the total lignan from the plant Fructus Arctii on aldose reductase was observed, suggesting its preventive potential on diabetic complications upon long term administration. Copyright © 2009 John Wiley & Sons, Ltd.
Orbital‐free effective embedding potential: Density‐matrix functional theory case
Authors: Pernal Katarzyna , Wesolowski Tomasz A.
Published: April 2009

Minimization of the Hohenberg–Kohn total energy functional EHK [ρ] in the presence of the constraint ρ − ρB ≥ 0, where ρB is some arbitrarily chosen electron density comprising integer number of electrons is considered. To access better numerical accuracy of approximations to EHK [ρ] in practice, the search for optimal ρ − ρB is performed using auxiliary quantities such as orbitals of a reference system of non‐interacting electrons [Wesolowski and Warshel, J Phys Chem 1993, 97, 8050] or a wavefunction‐like object corresponding to interacting electrons [Wesolowski, Phys Rev A 2008, 77, 012504]. In both cases, the condition ρ − ρB ≥ 0 leads to a local potential (orbital‐free effective embedding potential) of the same general form if expressed by means of universal density functionals. In this work, it is shown that the same local potential is obtained if the search for optimal ρ − ρB is performed among one‐particle reduced density matrices. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Multipartitioning Møller–Plesset perturbation theory: Size‐extensivity at third order and symmetry conservation
Authors: Rolik Zoltán , Szabados Ágnes
Published: April 2009

Multipartitioning multireference many‐body perturbation theory (Zaitevskii and Malrieu, Chem. Phys. Lett. 1995, 233, 597) is investigated with regard to symmetry and size‐extensivity. We show that the spin‐adapted formulation suffers from spatial symmetry breaking and propose a general symmetry‐conserving zero‐order Hamiltonian. We analyze size‐extensivity of various partitionings at the third order and find that extensivity holds if one‐particle quantities in the zero‐order Hamiltonian are properly chosen. In particular, third order of the spin‐adapted and general symmetry‐adapted theory prove to be extensive. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Pt(II)‐ion hydration: Structural and vibrational characteristics from theory and experiment
Authors: Stirling András , Bakó Imre , Kocsis László , Hajba László , Mink János
Published: April 2009

IR, Raman measurements, and ab initio molecular dynamics simulations have been carried out to describe and understand the structural and dynamic behavior of hydrated Pt2+ ion in water. The experiments have revealed strong red‐shifted O–H bond frequencies and blue‐shifted ligand deformation bands. The simulations have showed that the presence of the doubly charged cation and the enhanced hydrogen bond formations between the first and second shells result in significant structural changes in the first solvation shell, which in turn yield the characteristic shifts in the vibrational spectra. The weakening of the ligand O–H bonds and the strengthened hydrogen‐bonds around the cation can be accounted for as the result of the strong Coulombic field of the Pt(II)‐ion. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Quaternion‐based visual servo control in the presence of camera calibration error
Authors: Hu Guoqiang , Gans Nicholas , Dixon Warren
Published: April 2009

Visual servo control systems use information from images along with knowledge of the optic parameters (i.e. camera calibration) to position the camera relative to some viewed object. If there are inaccuracies in the camera calibration, then performance degradation and potentially unpredictable response from the visual servo control system may occur. Motivated by the desire to incorporate robustness to the camera calibration, different control methods have been developed. Previous adaptive/robust controllers (especially for six degree‐of‐freedom camera motion) rely heavily on properties of the rotation parameterization to formulate state estimates and a measurable closed‐loop error system. All of these results are based on the singular axis–angle parameterization. Motivated by the desire to express the rotation by a non‐singular parameterization, efforts in this paper address the question:Can state estimates and a measurable closed‐loop error system be crafted in terms of the quaternion parameterization when the camera calibration parameters are unknown? To answer this question, a contribution of this paper is the development of a robust controller and closed‐loop error system based on a new quaternion‐based estimate of the rotation error. A Lyapunov‐based analysis is provided which indicates that the controller yields asymptotic regulation of the rotation and translation error signals given a sufficient approximate of the camera calibration parameters. Simulation results are provided that illustrate the performance of the controller for a range of calibration uncertainty. Copyright © 2009 John Wiley & Sons, Ltd.
Catalytic Microtubular Jet Engines Self‐Propelled by Accumulated Gas Bubbles
Authors: Solovev Alexander A. , Mei Yongfeng , Bermúdez Ureña Esteban , Huang Gaoshan , Schmidt Oliver G.
Published: April 2009

Strain‐engineered microtubes with an inner catalytic surface serve as self‐propelled microjet engines with speeds of up to ≈2 mm s−1 (approximately 50 body lengths per second). The motion of the microjets is caused by gas bubbles ejecting from one opening of the tube, and the velocity can be well approximated by the product of the bubble radius and the bubble ejection frequency. Trajectories of various different geometries are well visualized by long microbubble tails. If a magnetic layer is integrated into the wall of the microjet engine, we can control and localize the trajectories by applying external rotating magnetic fields. Fluid (i.e., fuel) pumping through the microtubes is revealed and directly clarifies the working principle of the catalytic microjet engines.
Freestanding 3D Supramolecular Particle Bridges: Fabrication and Mechanical Behavior
Authors: Ling Xing Yi , Phang In Yee , Schönherr Holger , Reinhoudt David N. , Vancso G. Julius , Huskens Jurriaan
Published: April 2009

Freestanding particle bridges with controlled composition and macroscopic robustness are demonstrated by the use of supramolecular nanoparticle assembly. Self‐assembly of nanoparticles, templating, and supramolecular glue infiltration are combined to form stable and ordered three‐dimensional polystyrene particle composites on a polydimethylsiloxane stamp. Freestanding hybrid polystyrene nanoparticle bridges are obtained by transfer printing of the hybrid structures onto topographically patterned substrates via host–guest interactions. The mechanical robustness and rigidity of the particle bridges can be controlled by manipulating the layer‐by‐layer cycles of supramolecular glues of gold nanoparticles and dendrimers. Atomic force microscopy‐based microbending results, in particular the location and force‐dependent deflection behavior, confirm that the particle bridge fulfills the classical supported‐beam characteristics. As estimated from classical beam theory, the bending moduli of the particle bridges vary between 0.8 and 1.1 GPa, depending on the degree of filling by the supramolecular glues. Failure analysis on the particle structure indicates linear elastic behavior and a plastic deformation upon failure.
Comprehend and analyze knowledge networks to improve software evolution
Authors: Del Rosso Christian
Published: April 2009

When a set of people are connected by a set of meaningful social relationships we talk of a social network. A social network represents a social structure and the underlying structural patterns can be used to analyze and comprehend how people relate to each other and their emergent behavior as a group. Developing software is fundamentally a human activity. Developers cooperate and exchange knowledge and information, creating in fact, a particular type of social network that we call knowledge network. In this paper we investigate knowledge networks in software development teams by applying social network analysis and we use the Apache web server as a case study. By analyzing the structural communication and coordination patterns in Apache we have been able to identify the Apache knowledge network, highlight potential communication bottlenecks, and find brokers and important coordination points in the software development team. Furthermore, our work enables a software architect to analyze and maintain the organization and the software architecture aligned during software evolution. An important lesson that we have is that the analysis of knowledge networks constitutes an additional tool to be added to the traditional software architecture assessment methods. Copyright © 2009 John Wiley & Sons, Ltd.
Verification of real‐time systems design
Authors: Cambronero M. Emilia , Valero Valentín , Díaz Gregorio
Published: April 2009

The main objective of this paper is to present an approach to accomplish verification in the early design phases of a system, which allows us to make the system verification easier, specifically for those systems with timing restrictions. For this purpose we use RT‐UML sequence diagrams in the design phase and we translate these diagrams into timed automata for performing the verification by using model checking techniques. Specifically, we use the Object Management Group's UML Profile for Schedulability, Performance, and Time and from the specifications written using this profile we obtain the corresponding timed automata. The ‘RT‐UML Profile’ is used in conjunction with a very well‐known tool to perform validation and verification of the timing needs, namely, the UPPAAL tool, which is used to simulate and analyze the behaviour of real‐time dynamic systems described by timed automata. Copyright © 2009 John Wiley & Sons, Ltd.
System testing for object‐oriented systems with test case prioritization
Authors: Kundu Debasish , Sarma Monalisa , Samanta Debasis , Mall Rajib
Published: April 2009

This paper presents an approach to generate test cases from UML 2.0 sequence diagrams and subsequently prioritize those test cases using model information encapsulated in the sequence diagrams. The test cases generated according to the proposed approach satisfy the scenario coverage criterion and are suitable for system‐level testing. For prioritizing test cases, three different prioritization metrics are proposed. The values of these prioritization metrics can be analytically computed from the model information only. This paper also presents an approach to generate test data using a concept called rule‐based matrix. The prioritization metrics are used to control the number of test data without compromising the test adequacy. The effectiveness of the proposed approach has been verified using two industrial designs. Copyright © 2009 John Wiley & Sons, Ltd.