bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feedback–feedforward individual pitch control for wind turbine load reduction
Authors: Selvam K. , Kanev S. , van Wingerden J. W. , van Engelen T. , Verhaegen M. 
Published: April 2008

AbstractThis paper focuses on the problem of wind turbine fatigue load reduction by means of individual pitch control (IPC). The control approach has a two‐degree‐of‐freedom structure, consisting of an optimal multivariable LQG controller and a feedforward disturbance rejection controller based on estimated wind speed signals. To make the control design problem time invariant, all signals are transformed to the non‐rotating reference frame using the Coleman transformation. In the Coleman domain, the LQG control objective is minimization of the rotor tilt and yaw moments, whereas the feedforward controller tries to achieve even further improvement by rejecting the influence of the low‐frequency components of the wind on the rotor moments. To this end, the tilt‐ and yaw‐oriented components of the blade‐effective wind speeds are approximated using stochastic random walk models, the states of which are then augmented with the turbine states and estimated using a Kalman filter. The effects of these (estimated) disturbances on the controlled outputs are then reduced using stable dynamic model inversion. The approach is tested and compared with the conventional IPC method in simulation studies with models of different complexities. The results demonstrate very good load reduction at not only low frequencies (1p blade fatigue load reduction) but also at the 3p frequency, giving rise to fatigue load reduction of the non‐rotating turbine components. Copyright © 2008 John Wiley & Sons, Ltd.
Correction
Authors: Borghi Elaine 
Published: April 2008

Abstract‘Construction of the World Health Organization child growth standards: selection of methods for attained growth curves’ by Borghi E, de Onis M, Garza C, Van den Broeck J, Frongillo EA, Grummer‐Strawn L, Van Buuren S, Pan H, Molinari L, Martorell R, Onyango AW, Martines JC, for the WHO Multicentre Growth Reference Study Group (Statistics in Medicine 2006; 25:247–265).The correct reference for citation [59] was supposed to be [59] Dunn PK, Smyth GK. Randomized quantile residuals. Journal of Computational and Graphical Statistics 1996; 5(3):236–244.The authors offer their apologies to the authors of the cited paper and readers.
Reduced‐rank proportional hazards regression and simulation‐based prediction for multi‐state models
Authors: Fiocco Marta , Putter Hein , van Houwelingen Hans C. 
Published: April 2008

AbstractIn this paper we address two issues arising in multi‐state models with covariates. The first issue deals with how to obtain parsimony in the modeling of the effect of covariates. The standard way of incorporating covariates in multi‐state models is by considering the transitions as separate building blocks, and modeling the effect of covariates for each transition separately, usually through a proportional hazards model for the transition hazard. This typically leads to a large number of regression coefficients to be estimated, and there is a real danger of over‐fitting, especially when transitions with few events are present. We extend the reduced‐rank ideas, proposed earlier in the context of competing risks, to multi‐state models, in order to deal with this issue.The second issue addressed in this paper was motivated by the wish to obtain standard errors of the regression coefficients of the reduced‐rank model. We propose a model‐based resampling technique, based on repeatedly sampling trajectories through the multi‐state model. The same ideas are also used for the estimation of prediction probabilities in general multi‐state models and associated standard errors.We use data from the European Group for Blood and Marrow Transplantation to illustrate our techniques. Copyright © 2008 John Wiley & Sons, Ltd.
Heat‐Moisture Treatment and Enzymatic Digestibility of Peruvian Carrot, Sweet Potato and Ginger Starches
Authors: Vieira Fabiana C. , Sarmento Silene B. S. 
Published: April 2008

AbstractThe aim of this work was to study the effects of heat‐moisture treatment (27% moisture, 100°C, 16 h) and of enzymatic digestion (alpha‐amylase and glucoamylase) on the properties of sweet potato (SP), Peruvian carrot (PC) and ginger (G) starches. The structural modification with heat‐moisture treatment (HMT) affected crystallinity, enzyme susceptibility and viscosity profile. The changes in PC starch were the most pronounced, with a strong decrease of relative crystallinity (from 0.31 to 0.21) and a shift of X‐ray pattern from B‐ to A‐type. HMT of SP and G starch did not change the X‐ray pattern (A‐type). The relative crystallinity of these starches changed only slightly, from 0.32 to 0.29 (SP) and from 0.33 to 0.32 (G). The extent of these structural changes (PC > SP > G) altered the susceptibility of the starches to enzymatic attack, but not in same order (PC > G > SP). HMT increased the starches digestion, probably due to rearrangement of disrupted crystallites, increasing accessible areas to attack of enzymes. The viscosity profiles and values changed significantly with HMT, resulting in higher pasting temperatures, decrease of viscosity values and no breakdown, i.e., stability at high temperatures and shear rates. Changes in pasting properties appeared to be more significant for PC and SP starch, whereas the changes for G starch were small. Setback was minimized following HMT in SP and G starches.
Effect of Glycerol on Water Vapor Sorption and Mechanical Properties of Starch/Clay Composite Films
Authors: Yu Jian‐hua , Wang Jia‐li , Wu Xiao , Zhu Pu‐xin 
Published: April 2008

AbstractPlasticized starch/clay composite films were prepared by casting aqueous solutions containing oxidized corn starch, different concentrations of glycerol as a plasticizer and 5% clay (sodium montmorillonite, Na+‐MMT) on the basis of dry starch. The water‐binding properties of the composite films were evaluated by water vapor sorption isotherms at room temperature and various relative humidities (RHs). Mechanical properties and abrasion resistance were also analyzed for the films with varying glycerol contents at 68% RH and room temperature. Changes in water sorption isotherms suggested that glycerol interacted with both water and starch in a complicated way. A saturation phenomenon of glycerol, depending on RH, was observed based on the isotherms. Above this saturation content, phase separation of the system occurred with the appearance of free glycerol. According to mechanical performance and abrasion resistance, as well as water vapor sorption of the starch blend films, the three‐stage transition was presented to be related to the state of glycerol in the blend system, i.e. adsorption of glycerol onto H‐bonding sites of starch, supersaturation of glycerol as plasticizer and further supersaturation of glycerol. Only above the supersaturation content can glycerol play a plasticizer role in starch‐based composites.
MARS: a multiple access scheme with sender driven and reception first for smart antenna inad hocnetworks
Authors: Lai Wei Kuang , Tseng Kuo‐Shu , Chen Jiunn‐Ching 
Published: April 2008

AbstractThe deployment of directional antennas offers many advantages, such as transmission range extension, co‐channel interference reducing, the increasing of spatial reuse degree, throughput improving of networks, and transmission power saving. Hence, manyad hocMAC protocols with directional antennas have been proposed. However, these protocols do not provide significant improvement of network performance due to the lack of supporting multiple transmissions and receptions simultaneously. With the adaptive beam‐forming system (Smart Antenna), a newly designed MAC protocol (MARS) that enables nodes with multiple transmissions and receptions is proposed. Simulation results show that our MARS do exploit the advantage of space division multiple access. In terms of total number of data forward and complete sessions in bottleneck nodes, MARS achieves three times better than Novel and nine times better than IEEE 802.11. In addition, the end‐to‐end delay keeps very short. Copyright © 2008 John Wiley & Sons, Ltd.
Low hitting time random walks in wireless networks
Authors: Roberto Beraldi , Leonardo Querzoni , Roberto Baldoni 
Published: April 2008

AbstractRandom walks can be conveniently exploited for implementing probabilistic algorithms to solve many searching problems arised by distributed applications, for example, service discovery, p2p file sharing, etc. In this paper we consider random walks executed on uniform wireless networks and study how to reduce the expected number of walk steps required to reach a target, namely the hitting time. The latter is the main search performance metric of a random walk based algorithm, since it determines the average response to a search as well as its cost; thus, the actual convenience of using random walks compared to other solutions depends on achieving a low hitting time. We show how in uniform wireless networks, the natural implementation of a random walk which selects the next node to visit at random among all neighbors is not a good choice, since it has a strong negative effect on the hitting time. This paper studies such a negative effect analytically and proposes two neighbor selection rules aiming at reducing the hitting time. A simulation study confirms the benefits of the proposed solutions. Copyright © 2008 John Wiley & Sons, Ltd.
Stability‐aware multi‐metric clustering in mobile ad hoc networks with group mobility
Authors: Cheng Hui , Cao Jiannong , Wang Xingwei , Das Sajal K. , Yang Shengxiang 
Published: April 2008

AbstractClustering can help aggregate the topology information and reduce the size of routing tables in a mobile ad hoc network (MANET). The maintenance of the cluster structure should be as stable as possible to reduce overhead and make the network topology less dynamic. Hence, stability measures the goodness of clustering. However, for a complex system like MANET, one clustering metric is far from reflecting the network dynamics. Some prior works have considered multiple metrics by combining them into one weighted sum, which suffers from intrinsic drawbacks as a scalar objective function to provide solution for multi‐objective optimization. In this paper, we propose a stability‐aware multi‐metric clustering algorithm, which can (1) achieve stable cluster structure by exploiting group mobility and (2) optimize multiple metrics with the help of a multi‐objective evolutionary algorithm (MOEA). Performance evaluation shows that our algorithm can generate a stable clustered topology and also achieve optimal solutions in small‐scale networks. For large‐scale networks, it outperforms the well‐known weighted clustering algorithm (WCA) that uses a weighted sum of multiple metrics. Copyright © 2008 John Wiley & Sons, Ltd.
Aflatoxin control program for Peanuts
Authors: Dickens J. W. 
Published: April 2008

Abstract and SummaryUnder provisions of a USDA Marketing Agreement, an aflatoxin control program for peanuts produced in the United States is administered by the Peanut Administrative Committee composed of peanut growers and shellers. Regulations of this committee contain provisions about the quality of peanuts acquired from farmers, storage of unshelled peanuts, aflatoxin testing, quality and disposition of processed lots, and indemnification of handlers for losses caused by lots which test over 25 parts‐perbillion aflatoxin. Effects of the control program on aflatoxin concentrations in peanut products are discussed.
Solitary Fibrous Tumor of the Pleura: An Analysis of 13 Cases
Authors: Lu Chunlai , Ji Yuan , Shan Fei , Guo Weigang , Ding Jianyong , Ge Di 
Published: April 2008

AbstractBackgroundSolitary fibrous tumor of the pleura is a rare soft‐tissue tumor. In search of appropriate diagnosis and treatment methods, we present our experience with 13 patients.MethodsThe medical charts of 13 patients treated during the last 5 years were reviewed, as well as pathological records, including immunohistochemical stains. Follow‐up data were obtained. In addition, a literature review with regard to treatment and clinical outcome was performed.ResultsOur series consisted of four men and nine women with a mean age of 47 years. Two were diagnosed before operation with ultrasonography‐guided core needle biopsy. All patients underwent primary surgical treatment, and four of them were resected by video‐assisted thoracic surgery. Seven tumors were malignant and the other six were benign. Immunohistochemical staining showed nestin was positive in three malignant solitary fibrous tumors of pleura (3/7), which were negative for CD34. Except for one, all patients were followed‐up for 3 to 35 (mean, 14.5) months. Among them, one patient experienced a recurrence and one patient died of brain metastasis.ConclusionUltrasonography‐guided core needle biopsy combined with immunohistochemical analysis might be a safe and rapid method to provide a confirmatory diagnosis before resection. For smaller, pedunculated tumors, video‐assisted thoracic surgery could be a powerful and useful approach. We speculate that CD34‐negative and nestin‐positive might be a malignant marker for solitary fibrous tumor of pleura.
Invasion under a trade‐off between density dependence and maximum growth rate
Authors: Aikio Sami , Valosaari Kata‐Riina , Ranta Esa , Kaitala Veijo , Lundberg Per 
Published: April 2008

AbstractThe invasion of alien species and genotypes is an increasing concern in contemporary ecology. A central question is, what life‐history traits enable invasion amidst populations of wild species and conventional cultivars? In order to invade, the initially rare species must perform better than their resident competitors. We conducted a mathematical analysis and simulation of a two‐species extension of the Maynard Smith and Slatkin model for population dynamics in discrete time to study the role of density dependence as different types of competition in the invasion of new species. The type of density dependence ranged from scramble to contest competition. This led to intrinsic dynamics of the species range from point equilibrium to cycles and chaos. The traits were treated either as free parameters or constrained by a trade‐off resulting from a common fixed strength of density dependence or equilibrium density. Resident and intruder traits had up to ten‐fold differences in all of the parameters investigated. Higher equilibrium density of the intruder allowed invasion. Under constrained equilibrium density, an intrinsically stable intruder could invade an unstable resident population. Scramble competition made a population more susceptible to invasion than contest competition (e.g., limitation by light or territory availability). This predicts that a population which is mainly limited by food (or nutrients in plants) is more likely to be invaded than a population limited by a hierarchical competition, such as light among plants. The intruder population may have an effect on the resident population's dynamics, which makes the traditional invasion analysis unable to predict invasion outcome.
Acupuncture and dry needling in the management of myofascial trigger point pain: A systematic review and meta‐analysis of randomised controlled trials
Authors: Tough Elizabeth A. , White Adrian R. , Cummings T. Michael , Richards Suzanne H. , Campbell John L. 
Published: April 2008

ABSTRACTPain from myofascial trigger points is often treated by needling, with or without injection, although evidence is inconclusive on whether this is effective. We aimed to review the current evidence on needling without injection, by conducting a systematic literature review.We searched electronic databases to identify relevant randomised controlled trials, and included studies where at least one group were treated by needling directly into the myofascial trigger points, and where the control was either no treatment, or usual care; indirect local dry needling or some form of placebo intervention. We extracted data on pain, using VAS scores as the standard.Seven studies were included. One study concluded that direct dry needling was superior to no intervention. Two studies, comparing direct dry needling to needling elsewhere in the muscle, produced contradictory results. Four studies used a placebo control and were included in a meta‐analysis. Combining these studies (n=134), needling was not found to be significantly superior to placebo (standardised mean difference, 14.9 [95%CI, −5.81 to 33.99]), however marked statistical heterogeneity was present (I2=88%).In conclusion, there is limited evidence deriving from one study that deep needling directly into myofascial trigger points has an overall treatment effect when compared with standardised care. Whilst the result of the meta‐analysis of needling compared with placebo controls does not attain statistically significant, the overall direction could be compatible with a treatment effect of dry needling on myofascial trigger point pain. However, the limited sample size and poor quality of these studies highlights and supports the need for large scale, good quality placebo controlled trials in this area.
Hydrologic and climatic implications of stable isotope and minor element analyses of authigenic calcite silts and gastropod shells from a mid-Pleistocene pluvial lake, Western Desert, Egypt
Authors: Kieniewicz Johanna M. , Smith Jennifer R. 
Published: April 2008

AbstractAuthigenic calcite silts at Wadi Midauwara in Kharga Oasis, Egypt, indicate the prolonged presence of surface water during the Marine Isotope Stage 5e pluvial phase recognized across North Africa. Exposed over an area of ∼ 4.25 km2, these silts record the ponding of water derived from springs along the Libyan Plateau escarpment and from surface drainage. The δ18O values of these lacustrine carbonates (− 11.3‰ to − 8.0‰ PDB), are too high to reflect equilibrium precipitation with Nubian aquifer water or water of an exclusively Atlantic origin. Mg/Ca and Sr/Ca of the silts have a modest negative covariance with silt δ18O values, suggesting that the water may have experienced the shortest residence time in local aquifers when the water δ18O values were highest. Furthermore, intra-shell δ18O, Sr/Ca, and Ba/Ca analyses of the freshwater gastropodMelanoides tuberculataare consistent with a perennially fresh water source, suggesting that strong evaporative effects expected in a monsoonal climate did not occur, or that dry season spring flow was of sufficient magnitude to mute the effects of evaporation. The input of a second, isotopically heavier water source to aquifers, possibly Indian Ocean monsoonal rain, could explain the observed trends in δ18O and minor element ratios.
Pleistocene ice and paleo-strain rates at Taylor Glacier, Antarctica
Authors: Aciego S.M. , Cuffey K.M. , Kavanaugh J.L. , Morse D.L. , Severinghaus J.P. 
Published: April 2008

AbstractIce exposed in ablation zones of ice sheets can be a valuable source of samples for paleoclimate studies and information about long-term ice dynamics. We report a 28-km long stable isotope sampling transect along a flowline on lower Taylor Glacier, Antarctica, and show that ice from the last glacial period is exposed here over tens of kilometers. Gas isotope analyses on a small number of samples confirm our age hypothesis. These chronostratigraphic data contain information about past ice dynamics and in particular should be sensitive to the longitudinal strain rate on the north flank of Taylor Dome, averaged over millennia. The imprint of climatic changes on ice dynamics may be discernible in these data.
Younger Dryas to mid-Holocene environmental history of the lowlands of NW Transylvania, Romania
Authors: Feurdean Angelica , Mosbrugger Volker , Onac Bogdan P. , Polyak Victor , Veres Daniel 
Published: April 2008

AbstractPollen, micro-charcoal and total carbon analyses on sediments from the Turbuta palaeolake, in the Transylvanian Basin of NW Romania, reveal Younger Dryas to mid-Holocene environmental changes. The chronostratigraphy relies on AMS14C measurements on organic matter and U/Th TIMS datings of snail shells. Results indicate the presence ofPinusandBetulaopen woodlands with small populations ofPicea,Ulmus,AlnusandSalixbefore 12,000 cal yr BP. A fairly abrupt replacement ofPinusandBetulabyUlmus-dominated woodlands at ca. 11,900 cal. yr BP likely represents competition effects of vegetation driven by climate warming at the onset of the Holocene. By 11,000 cal yr BP, the woodlands were increasingly diverse and dense with the expansion ofQuercus,FraxinusandTilia, the establishment ofCorylusand the decline of upland herbaceous and shrubs taxa. The marked expansion ofQuercusaccompanied byTiliabetween 10,500 and 8000 cal yr BP could be the result of low effective moisture associated with both low elevation of the site and with regional change towards a drier climate. At 10,000 cal yr BP,Corylusspread across the region, and by 8000 cal yr BP it replacedQuercusas a dominant forest constituent, with only little representation ofPicea abies.Carpinusbecame established around 5500 cal yr BP, but it was only a minor constituent in local woodlands until ca. 5000 cal yr BP. Results from this study also indicate that the woodlands in the lowlands of Turbuta were never closed.
The ThirdDemocracy:Tocqueville's Views of America after 1840
Authors: CRAIUTU AURELIAN , JENNINGS JEREMY 
Published: April 2008

Tocqueville'sDemocracy in Americaoffered the image of an accomplished and successful democratic regime. Although Tocqueville never wrote a third volume, he continued to be interested in American political events and exchanged a number of important letters with his American friends after 1840. Did Tocqueville change his views on America outlined in the two volumes published in 1835 and 1840? If so, did the evolution of his views of America affect his theory of democracy? The paper answers these questions by examining Tocqueville's unduly neglected correspondence with his American friends. It seeks to reconstruct what Volume Three ofDemocracy in Americamight have looked like if it had ever been written. In these letters, Tocqueville addressed important topics such as the instability of the market and the immaturity of American democracy, issues that didnotloom large in the two published volumes. The paper shows that in the last years of his life Tocqueville became very disenchanted with American political life and reassessed some of his previous views of American democracy.I, who am half Yankee.Tocqueville (1986, 185)
Thrips (Thysanoptera) identification using artificial neural networks
Authors: Fedor P. , Malenovský I. , Vaňhara J. , Sierka W. , Havel J. 
Published: April 2008

AbstractWe studied the use of a supervised artificial neural network (ANN) model for semi-automated identification of 18 common European species of Thysanoptera from four genera:AeolothripsHaliday (Aeolothripidae),ChirothripsHaliday,DendrothripsUzel, andLimothripsHaliday (all Thripidae). As input data, we entered 17 continuous morphometric and two qualitative two-state characters measured or determined on different parts of the thrips body (head, pronotum, forewing and ovipositor) and the sex. Our experimental data set included 498 thrips specimens. A relatively simple ANN architecture (multilayer perceptrons with a single hidden layer) enabled a 97% correct simultaneous identification of both males and females of all the 18 species in an independent test. This high reliability of classification is promising for a wider application of ANN in the practice of Thysanoptera identification.