bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling and forecasting snowmelt runoff process using the HBV model in the eastern part of Turkey
Authors: Şorman A. Arda , Şensoy A. , Tekeli A. E. , Şorman A. Ü. , Akyürek Z. 
Published: January 2009

AbstractSnowmelt runoff in the mountainous eastern part of Turkey is of great importance as it constitutes 60–70% in volume of the total yearly runoff during spring and early summer months. Therefore, determining the amount and timing of snowmelt runoff especially in the Euphrates basin, where large dams are located, is an important task in order to use the water resources of the country in an optimal manner.The HBV model, being one of the well‐known conceptual hydrological models used more than 45 countries over the world, is applied for the first time in Turkey to a small basin of 242 km2 on the headwaters of Euphrates river for 2002–2004 water years. The input data are provided from the automatic snow‐meteorological stations installed at various locations and altitudes in upper Euphrates basin operating in real‐time. Since ground‐based observations can only represent a small part of the region of interest, spatially and temporally distributed snow cover data are acquired through the use of Moderate Resolution Imaging Spectroradiometer (MODIS) optical satellite. In the first part of the study, an automatic model parameter estimation method, Shuffled Complex Evolution, University of Arizona (SCE‐UA), is utilized to calibrate the HBV model parameters with a multi‐variable criteria using runoff as well as snow‐covered area (SCA) to ensure the internal validity of the model. Results show that calibrations against SCA in addition to discharge simulate discharge nearly as well as calibrations against discharge only, but further suggest that longer time periods and more study catchments should be included to achieve more comprehensible conclusions. In the second part of the study, the calibrated HBV model is applied to forecast runoff with a 1‐day lead time using gridded input data from Mesoscale Model 5 (MM5) for the 2004 snowmelt period. Promising results indicate the possible operational use of runoff forecasting driven by numerical weather prediction data for flood mitigation, reservoir operation and dam safety. Copyright © 2009 John Wiley & Sons, Ltd.
Reconstructing snow water equivalent in the Rio Grande headwaters using remotely sensed snow cover data and a spatially distributed snowmelt model
Authors: Molotch Noah P. 
Published: January 2009

AbstractSnow covered area (SCA) observations from the Landsat Enhanced Thematic Mapper (ETM+) were used in combination with a distributed snowmelt model to estimate snow water equivalent (SWE) in the headwaters of the Rio Grande basin (3,419 km2) ‐ a spatial scale that is an order of magnitude greater than previous reconstruction model applications. In this reconstruction approach, modeled snowmelt over each pixel is integrated over the time of ETM+ observed snow cover to estimate SWE. Considerable differences in the magnitude of SWE were simulated during the study. Basin‐wide mean SWE was 2·6 times greater in April 2001 versus 2002. Despite these climatological differences, the model adequately recovered SWE at intensive study areas (ISAs); mean absolute SWE error was 23% relative to observed SWE. Reconstruction model SWE errors were within one standard deviation of the mean observed SWE over 37 and 55% of the four 16‐km2 intensive field campaign study sites in 2001 and 2002, respectively; a result comparable to previous works at much smaller scales. A key strength of the technique is that spatially distributed SWE estimates are not dependent upon ground‐based observations of SWE. Moreover, the model was relatively insensitive to the location of forcing observations relative to commonly used statistical SWE interpolation models. Hence, the reconstruction technique is a viable approach for obtaining high‐resolution SWE estimates at larger scales (e.g. >1000 km2) and in locations where detailed hydrometeorological observations are scarce. Copyright © 2009 John Wiley & Sons, Ltd.
Towards a technological ripening index for olive oil fruits
Authors: Cherubini Chiara , Migliorini Marzia , Mugelli Marco , Viti Paolo , Berti Andrea , Cini Enrico , Zanoni Bruno 
Published: January 2009

AbstractBACKGROUND: The aim of this work was to study the evolution of sugar and oil contents in Frantoio cultivar olives during ripening in order to propose a technological ripening index for olive oil fruits. Olive fruits were picked at nine different farms once a week from the beginning of September to the beginning of December during three crop seasons.RESULTS: As a result of the biochemical phenomenon of oil formation in olive fruits, sugar concentration during ripening was shown to follow a sigmoidal decrease, which recurred periodically in different microclimates over years. This trend resulted to be the cause of an opposite sigmoidal increase in oil content. Experimental data for sugar and oil contents were also statistically related by significant linear relationships. In addition, it was observed that reaching a minimum environmental temperature of ⩽10 °C resulted in a definite minimum asymptotic value for sugars.CONCLUSION: Sugar concentration can be proposed as an accurate, reproducible index for technological ripening of olive oil fruits by the following prediction function: proper ripening degree of olives corresponds to achievement of a constant minimum value for sugar content and, consequently, a constant maximum value for oil content, associated with reduced risk of fermentation activities of olive paste. Copyright © 2009 Society of Chemical Industry
Plasmonic metasurfaces for waveguiding and field enhancement
Authors: Radko I.P. , Volkov V.S. , Beermann J. , Evlyukhin A.B. , Søndergaard T. , Boltasseva A. , Bozhevolnyi S.I. 
Published: January 2009

AbstractThe explosive progress in nanoscience has led to uncovering and exploring numerous physical phenomena occurring at nanoscale, especially when metal nanostructures are involved so that optical fields and electronic oscillations can be resonantly coupled. The latter is the subject of (nano) plasmonics with implications extending from subwavelength waveguiding to localized field enhancements. In this review paper, we consider making use of various phenomena related to multiple scattering of surface plasmons (SPs) at periodically and randomly (nano) structured metal surfaces. After reviewing the SP waveguiding along channels in nanostructured areas exhibiting band‐gap and localization effects, SP‐driven field enhancement in random structures and plasmonic fractal drums is discussed in detail. SP manipulation and waveguiding using periodic nanostructures on the long‐wavelength side of the band gap is also considered.
A simple mathematical model for seasonal planktonic blooms
Authors: Chatterjee Samrat , Venturino Ezio , Chakraborty Subhendu , Chattopadhyay Joydev 
Published: January 2009

AbstractWe show how the inclusion of the defense strategy by different species can alter the prediction of simple models. One of the defense strategy by the phytoplankton population against their grazer is the release of toxic chemicals. In turn the zooplankton population reduces there predation rate over toxin producing phytoplankton (TPP) to protect themselves from those toxic chemicals. Thus, when the level of toxicity is high, the grazing pressure is low and when the level of toxicity is low or when the toxin is absent, the grazing pressure is high. Here we have considered a TPP–zooplankton system where the rate of toxin liberation and the predation rate vary with zooplankton abundance. We observe that our proposed model has the potential to show different dynamical behaviour that are similar to that seen in real‐world situations. Further, we consider three different functional forms for the distribution of the toxins and compare them using latin hypercube sampling technique and found that the functional forms seem to have no effect in determining the final outcome of the system. Copyright © 2009 John Wiley & Sons, Ltd.
Examining how advocacy groups build relationships on the Internet
Authors: Waters Richard D. , Lord Meredith 
Published: January 2009

Abstract

In 2006, the Animal Enterprise Terrorism Act (AETA) became American law after brief Congressional discussions despite the public outcries from animal rights organizations. The AETA made it a federal terrorist crime to harm any animal enterprise financially, which could include legal forms of protests and boycotts. Members of the “Stop AETA” coalition failed to draw attention to the legislation. The relationship management theory of public relations provides a framework to determine how well the coalition members developed relationships with like‐minded individuals and the media. Results from a content analysis of the coalition members' Web sites revealed that nonprofit organizations and citizen‐advocacy groups attempted to develop relationships through a variety of strategies, including making the visit a positive experience, being open and transparent in their advocacy efforts, and providing access to coalition leaders. The results suggest that the coalition was unable to generate much news coverage for the issue because coalition members did not sufficiently reach out to cultivate relationships with journalists. Specific suggestions are provided for future advocacy groups to use the Internet to develop and cultivate relationships with key stakeholder groups.
Copyright © 2009 John Wiley & Sons, Ltd.
Smoking and acute urinary retention: The Olmsted County study of urinary symptoms and health status among men
Authors: Sarma Aruna V. , Jacobson Debra J. , St. Sauver Jennifer L. , Lieber Michael M. , Girman Cynthia J. , Nehra Ajay , Jacobsen Steven J. 
Published: January 2009

AbstractBACKGROUNDPrevious reports have suggested an inverse relationship between smoking and surgery for benign prostatic hyperplasia (BPH). We hypothesized that acute urinary retention (AUR), an adverse outcome of this disease and indication for surgical treatment, may be related to smoking.METHODSStudy subjects were randomly selected from Olmsted County men aged 40–79 identified through the Rochester Epidemiology Project. Of the 3,854 eligible men, 2,089 (54%) completed a questionnaire that included the American Urological Association Symptom Score and assessed smoking status. Community medical records were examined for occurrence of AUR with documented catheterization in the subsequent 10 years and occurrence of BPH surgery. Proportional hazard models were used to assess the relationship between baseline smoking status and subsequent retention.RESULTSIn the 18,307 person‐years of follow‐up, 114 men had AUR. When compared to 727 never‐smokers, there was a trend among the 336 current smokers to be at lower risk (Relative risk (RR) = 0.62, 95% Confidence Interval (CI) = 0.33, 1.18) whereas the 1,026 former smokers were at similar risk to non‐smokers (RR = 1.0, 95%CI = 0.67, 1.46). Among men with moderate‐severe symptoms at baseline, current smokers were at lower risk of retention compared to non‐smokers (RR = 0.65, 95%CI = 0.22, 1.91) but the association approached the null among those with none‐mild symptoms (RR = 0.91, 95% CI = 0.40, 2.06).CONCLUSIONSCommunity‐dwelling men who currently smoke may be at a modestly reduced risk of AUR. The magnitude of this association is sufficiently small that it seems unlikely that this explains a sizable proportion of the inverse association between smoking and surgically treated BPH. Prostate 69: 699–705, 2009. © 2009 Wiley‐Liss, Inc.
Asymmetry effect on the spin relaxation in quantum dot structures
Authors: Zinovieva A. F. , Dvurechenskii A. V. , Stepina N. P. , Deryabin A. S. , Nikiforov A. I. , Rubinger R. M. , Sobolev N. A. , Leitão J. P. , Carmo M. C. 
Published: January 2009

AbstractSpin resonance of electron states in a Ge/Si heterosystem with Ge quantum dots has been investigated. Electron localization in the strain‐induced potential wells in Si in the vicinity of the Ge dots is confirmed by an analysis of the obtained g‐tensor values. A well pronounced anisotropy of the linewidth is explained in terms of an effective magnetic field lying in the plane of the quantum dot array. This magnetic field arises during the tunnelling of electrons between quantum dots and leads to an acceleration of the spin relaxation. The origin of the field is the structure‐induced asymmetry of electron potential wells. Two ways of increasing the spin lifetime are suggested: 1) creation of a higher‐symmetry confinement potential for electrons; 2) growth of a well‐separated quantum dot array (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of 3C‐SiC nanowires on nickel coated Si(100) substrate using dichloromethylvinylsilane and diethylmethylsilane by MOCVD method
Authors: Hyun J.‐S. , Nam S.‐H. , Kang B.‐C. , Boo J.‐H. 
Published: January 2009

AbstractWe have grown 3C‐SiC nanowires on nickel coated Si(100) substrates using single source precursors by thermal metal‐organic chemical vapor deposition (MOCVD) method. Dichloromethylvinylsilane (CH2CHSi(CH3)Cl2) and diethylmethylsilane (CH3SiH(C2H5)2) were used as a single precursor without any carrier and bubbler gas. 3C‐SiC nanowires with 40 ∼ 100 nm diameter could grow on substrates at temperature as low as 900 °C. XRD pattern showed that SiC nano‐wires were cubic silicon carbide. TEM analysis showed that an amorphous carbon layer surrounds the as‐deposited SiC nanowires, and the 3C‐SiC nanowire has [111] growth direction with well‐crystallized structure. XPS and EDX analyses showed that the as‐obtained SiC nanowire has an atomic Si and C composition of about 1.0:1.2, suggesting possible applications for both electronic devices and field emitters. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarization control of nonpolar‐oriented InGaN quantum‐well emission by utilizing (Al)InGaN alloy substrates
Authors: Yamaguchi A. Atsushi 
Published: January 2009

AbstractThe polarization properties of InGaN quantum wells on nonpolar AlInGaN alloy substrates are calculated numerically using the 6×6 k·p Hamiltonian. It is shown that the polarization direction of quantum‐well emission changes, depending on the substrate alloy composition and quantum well width, and that these polarization switches are caused by the strain anisotropy and quantum confinement effects in the quantum wells. The calculations indicate that the utilization of InGaN or AlInGaN alloy substrates can be beneficial in obtaining desirable polarization properties for the formation of cleaved‐facet cavity mirrors in laser diodes on nonpolar substrates. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dislocation density in AlN grown on multistacked GaN/AlN quantum dot layers by molecular beam epitaxy
Authors: Managaki Nobuto , Iizuka Norio 
Published: January 2009

AbstractThe influence of GaN/AlN quantum dots (QDs) on crystalline quality of AlN grown on multistacked QD layers was studied as a function of the GaN deposition. Dislocations in the AlN grown on the QD layers were bent by the existence of the QD layers and the dislocation density in the AlN was one order of magnitude smaller than that in AlN grown on sapphire substrate. In the measurement of Raman spectra, AlN E2 frequency and GaN A1 (LO) frequency depended on the deposition of GaN. The dependence of these two frequencies was strongly correlated. This suggests that the crystalline quality of AlN is affected by the growth condition of the GaN QDs and size distribution of QDs was of great importance in reduction of the dislocation density in AlN by using the QD layers as a buffer layer. The reduction of dislocation in the AlN is efficient when the small QDs are grown uniformly but inefficient when the large QDs are grown. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of isotopic natGa15N by molecular‐beam epitaxy
Authors: Yao Yong‐zhao , Ohgaki Takeshi , Matsumoto Kenji , Sakaguchi Isao , Wada Yoshiki , Haneda Hajime , Sekiguchi Takashi , Ohashi Naoki 
Published: January 2009

AbstractIsotopically enriched gallium nitride films, Ga14N and Ga15N, have been fabricated by molecular‐beam epitaxy to study the effects of nitrogen atomic mass variation on structures and properties of GaN. The phonon frequency shift due to the isotopic substitution was clearly observed using Raman spectroscopy. The lattice constants of Ga15N differed from those of Ga14N; the unit cell volume of Ga15N was approximately 0.06% less than that of Ga14N. Temperature‐dependent photoluminescence measurements revealed that the recombination mechanism in Ga14N and Ga15N was the same in the temperature range of 4‐50 K, and the band gap energy difference was Eg15‐Eg14 = 6.0 ± 0.1 meV. This Eg difference is discussed in terms of volume shrinkage and change in phonon‐electron interaction due to isotopic substitution. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flip‐chip, micro‐pixellated InGaN light‐emitting diode arrays: attractive sources for micro‐displays, colour conversion, and fluorescence detection
Authors: Gong Z. , Massoubre D. , McKendry J. , Zhang H. X. , Griffin C. , Guilhabert B. , Gu E. , Girkin J. M. , Dawson M. D. , Rael B. R. , Henderson R. K. 
Published: January 2009

AbstractFlip‐chip micro‐pixellated InGaN light‐emitting diode (micro‐LED) arrays fabricated in both matrix‐addressable and individually‐addressable formats were presented. Despite different addressing schemes, all these LED arrays exhibited superior device operation performance in terms of power output, emission uniformity, and current handling capability, in contrast to the top‐emitting counterparts. With the aid of custom‐designed driver circuitry, a wide range of promising applications have been demonstrated by using these micro‐light sources including micro‐display, colour conversion, and fluorescence detection. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐situ doping and implantation of GaN layers with Mn
Authors: Sofer Zdeněk , Sedmidubský David , Stejskal Josef , Hejtmánek Jiří , Maryško Miroslav , Jurek Karel , Havránek Vladimír , Macková Anna , Hardtdegen Hilde , Václavů Michal 
Published: January 2009

AbstractIn this paper we present a growth of Ga1–xMnxN layers by MOVPE and ion implantation of GaN layers with Mn. The Mn concentration detected by electron microprobe and PIXE was well below the solubility limit, ranging from 0.2 to 1.1 at.%. Implanted doses of Mn ions were in the range 1x1016‐5x1016 Mn atoms.cm–2 with energy of 330 keV. The analysis of the MOVPE deposition process of Ga1–xMnxN thin films revealed an unfavorable ratio between the apparent Mn concentration in the gas phase and its doping level in the deposited layer. On the other hand, the incorporation of Mn has a positive effect on the resulting surface morphology. The optimal deposition temperature of 1000 °C was found out as a compromise between the layer quality and Mn concentration. In both in‐situ grown and implanted samples, a ferromagnetic component persisting up to room temperature and a prevailing paramagnetic phase were observed. The ferromagnetic moment observed in implanted samples was influenced by free carrier concentration in GaN layers which were used for implantation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study on growth and electrical performance of double‐heterostructure AlGaN/GaN/AlGaN field‐effect‐transistors
Authors: Vescan Andrei , Hardtdegen Hilde , Ketteniß Nico , Eickelkamp Martin , Noculak Achim , Goliasch Jens , Ahe Martina v. d. , Bay Helge Lago , Schäpers Thomas , Kalisch Holger , Grützmacher Detlev , Jansen Rolf H. 
Published: January 2009

AbstractDevice simulations and first experimental results on double‐heterostructure (DH) AlGaN/GaN/AlGaN field effect transistors are presented. Simulations show that above an Al content of approximately 10% in the back GaN/AlGaN barrier, a hole channel could be formed. On the other hand the DH is shown to reduce the electric field in the regions adjacent to the channel and to suppress trapping. First experimental results confirm the existence of the 2‐dimensional electron gas for a back barrier Al content of 5%. The device performance although strongly limited by the material quality, is comparable to that of conventional structures, promising significant potential once design and material issues are resolved. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time resolved measurement of longitudinal mode competition in 405 nm (Al,In)GaN laser diodes
Authors: Schmidtke Bernd , Braun Harald , Schwarz Ulrich T. , Queren Désirée , Schillgalies Marc , Lutgen Stephan , Strauß Uwe 
Published: January 2009

AbstractWe investigate the spectral and temporal behavior of conventional narrow ridge (Al,In)GaN laser diodes (LDs) emitting at a wavelength of about 405 nm, grown on low dislocation density GaN substrate. In time resolved measurements of the lasing spectra we find a quasi‐periodic hopping among several longitudinal modes, which leads to time‐averaged multimode‐like output spectra. The experimental data are compared to a multimode rate equation model that was adapted to the (Al,In)GaN material system. While mode hopping is well studied for other material systems, we investigate whether this mechanism is identical in blue (Al,In)GaN LDs (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auger losses in GaN‐based quantum wells: Microscopic theory
Authors: Pasenow B. , Koch S. W. , Hader J. , Moloney J. V. , Sabathil M. , Linder N. , Lutgen S. 
Published: January 2009

AbstractFully microscopic many‐body models are used to study the importance of radiative and Auger carrier losses in InGaN/GaN quantum wells. Since the usual direct bandto‐band Auger losses are too small to explain the experimentally observed droop of the external quantumefficiency in such structures, phonon assisted Auger processes are discussed. First numerical estimates indicate that the resulting losses constitute an important intrinsic loss process in InGaN/GaN quantum wells (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Statistical inference of risk difference in K correlated 2×2 tables with structural zero
Authors: Wang Shun‐Fang , Tang Nian‐Sheng , Zhang Bo , Wang Xue‐Ren 
Published: January 2009

AbstractK correlated 2×2 tables with structural zero are commonly encountered in infectious disease studies. A hypothesis test for risk difference is considered in K independent 2×2 tables with structural zero in this paper. Score statistic, likelihood ratio statistic and Wald‐type statistic are proposed to test the hypothesis on the basis of stratified data and pooled data. Sample size formulae are derived for controlling a pre‐specified power or a pre‐determined confidence interval width. Our empirical results show that score statistic and likelihood ratio statistic behave better than Wald‐type statistic in terms of type I error rate and coverage probability, sample sizes based on stratified test are smaller than those based on the pooled test in the same design. A real example is used to illustrate the proposed methodologies. Copyright © 2009 John Wiley & Sons, Ltd.