bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nematology Situation in the United States and Priority Areas in Research1
Authors: GUNDY S.D. VAN 
Published: April 2008

After a review of the state of plant nematology research and teaching in the USA, the author discusses current research progress on the biology and ecology of nematodes (insect parasites, microbial and fungal feeders, nematodes as model biological systems), and on plant parasitic nematodes and their control by biological cultural and chemical methods and the use of resistant varieties. The impact of Integrated Pest Management and modeling methods is discussed. The achievements of the International Meloidogyne Project are briefly reviewed.RESUMESituation de la nématologie aux Etats‐Unis et recherches à caractère prioritaireL'étude est consacrée à la façon d'aborder les problèmes nématologiques aux Etats‐Unis, notamment recherche et formation, et aux principaux progrès réalisés dans la connaissance de la biologie et de l'écologie de ces ravageurs (entornoparasitisme. mycotrophie, nénidtodes en tant qu'organismes modèles pour la recherche). La lutte contre les nématodes nuisibles est entreprise par les méthodes biologiques, culturales et chimiques et par l'utilisation des variétés résistantes. L'impact de la protection intégrée et de la modélisation est mis en évidence. Enfin, l'auteur se référe aux travaux réalisés dans le cadre du Projet International sur les Meloidogyne.
Nematode Problems in Field Crops and Vineyards1
Authors: WEISCHER B. 
Published: April 2008

The most important nematode in sugar‐beet production is Helerodera schachtii. Since breeding for resistance is difficult due to sterility barriers, crop rotation and nematicides are the main control methods. In crop rotation a three‐year course often leads to a population increase whilst a four‐year course is usually safe. In potato production losses by yield reduction are equalled by losses to plant health and quarantine regulations. A serious problem is the occurrence of pathotypes in both species of potato cyst‐nematodes that can multiply on resistant varieties. In cereals Heterodera avenae is a main factor limiting production of wheat and barley. Since the application of nematicides is uneconomic in most cereals, the use of resistant plant cultivars is the most important means of control. In viticulture Meloidogyne spp. and the virus vector Xiphinema index cause severe damage. Nematicidal soil treatment is the most important means of control. In order to achieve persistent effects at sufficient depth, high dosages are required and this causes pollution problems.RESUMEProblèmes dus aux nématodes dans les grandes cultures et les vignoblesLe nématode le plus dangereux pour la production de betteraves sucriéres est Heterodera schachtii. Etant donné que la sélection de variétés résistantes se révèle difficile face aux barrières de stérilité, la lutte se concentre sur l'assolement et les traitements nématicides. Une rotation de trois ans paraît insuffisante pour limiter sufflsamment le développement des populations; il faut done un intervalle de quatre ans. En ce qui concerne la pomme de terre, les pertes dues directement aux nématodes équivalent à celles qui sont enregistrées pour satisfaire à la réglementation phytosanitaire. L'utilisation de la résistance génétique est compliquée en raison de l'existence, pour les deux espèces de nématodes à kystes, de pathotypes capables d'attaquer les variétés résistantes. Heterodera avenae est un important facteur limitant le rendement du blé et de l'orge. Les variétés résistantes offrent le meilleur moyen de lutte, puisque les traitements nématicides sont trop coûteux. En viticulture, ce sont les espéces de Meloidogyne et le vecteur de virus Xiphinema index qui sont les plus redoutables. Le traitement du sol à l'aide de nématicides constitue le principal moyen de lutte utilisé. Cependant, la nécessité d'assurer un effet persistant à une profondeur suffisante exige l'emploi de doses élevées, ce qui entraîne des problèmes de résidus.
Nematology at the Commonwealth Institute of Helminthology1
Authors: FRANKLIN M.T. 
Published: April 2008

The Commonwealth Institute of Helminthology publishes in the nematological field (Helminthological Abstracts, descriptions of Plant‐parasitic Nematodes, Nematicide Index etc.), provides a nematode identification service, and contributes to nematode taxonomy.RESUMEService d'identification et établissement de documents signalétiques assurés par le Commonwealth Institute of HelminthologyL'Institut d'Helminthologie du Commonwealth Agricultural Bureaux édite des publications nématologiques telles que « Helminthological Abstracts », descriptions concernant les nématodes parasites des plantes, index des nématicides, etc. II assure un service d'identification des nématodes et contribue directement à la taxonomie de ceux‐ci.
Control of Verticillium dahliae on tomato in Tunisia by resistant cultivars and soil disinfestation1
Authors: MOENS M. , AICHA B. BEN 
Published: April 2008

Verticillium dahliae is an important soil‐borne pathogen of vegetables in the central coastal region of Tunisia. Cultivation of resistant tomato cultivars does not always give satisfaction as they do not fulfil agronomic requirements (earliness, fruit size and yield). Soil treatment with dichloropropene/methyl isothiocyanate mixture (36.12 g + 16.45 g m‐2) gave excellent control of verticillium wilt and nearly tripled the yield of the susceptible cultivar H63–5. Dazomet (60 g m‐2) caused only slight disease depression and less yield increase.Parmi les pathogènes édaphiques des cultures maraîchères, Verticillium dahliae occupe une place importante dans le Sahel tunisien. Bien que les cultivars résistants donnent entière satisfaction sur le plan phytopathologique, leur utilisation est limitée à cause de leurs faiblesses agronomiques (précocité, calibre des fruits et rendement). La désinfection du sol avec le mélange dichloropropène/méthyl‐isothiocyanate (36, 12 g + 16,45 g m‐2) réduit considérablement la verticilliose et triple presque le rendement de l'hybride sensible H63‐5. L'incidence du dazomet (60 g m‐2) sur la trachéomycose et le rendement était moindre.
Virus transmis par les graines de légumineuses: méthode d'évaluation rapide du taux de transmission d'un lot de graines1
Authors: MAURY Y. , BOSSENNEC J. M. , BOUDAZIN G. 
Published: April 2008

AbstractLa technique ELISA est utilisée pour évaluer le taux d'infection de lots de graines de soja et de graines de pois, respectivement par le soybean mosaic virus et le pea seed‐borne mosaic virus. Couplée à une méthode d'analyse par groupes, cette technique permet de tester un grand nombre de graines si la précision requise l'exige. Une mise au point préalable est nécessaire pour chaque cultivar à analyser: elle porte sur le nombre maximal de graines par groupe et sur les modalités du broyage dans les conditions de routine. L'analyse des lots de graines peut apporter une double information: lorsque le virus des téguments est pris en compte dans le test, le résultat obtenu est une estimation par défaut du pourcentage de plantes infectées avant la récolte; au contraire, lorsque seul le virus des embryons est dosé, le résultat traduit le pourcentage de sources primaires d'infection lors de la prochaine culture.
Non‐double‐couple mechanism of moderate earthquakes near Zakynthos, Greece, April 2006; explanation in terms of complexity
Authors: Zahradnik J. , Sokos E. , Tselentis G.‐A. , Martakis N. 
Published: April 2008

ABSTRACTDeviation of earthquakes from the double‐couple mechanism is an important, but delicate tool to study their source processes. For assessing the double‐couple percentage, the paper suggests to complement the standard least‐square moment‐tensor retrieval with a hierarchic spatio‐temporal grid search, progressively closer to the true source position and time. It enables identification of the double‐couple percentage convergence, while its limit is the resulting double‐couple percentage value, or range. The so‐called double‐couple percentage (DC%) versus correlation plots are introduced and difficulties of the double‐couple percentage assessment are discussed. It is proved that even close to the true source position, where the strike‐dip‐rake angles are already stable (within a few degrees), the double‐couple percentage may still vary by dozens of per cent. Moreover, even at the optimum spatial position, the double‐couple percentage estimate is extremely sensitive (0 to 100%) to small variations of the subevent origin time. This behaviour is explained in terms of the source complexity, implying a time‐dependent moment tensor. Therefore, the double‐couple percentage of complex events depends on the studied frequency band and, in general, also on the station azimuth. This explains broad variations of the double‐couple percentage reports among seismic agencies. Three earthquakes of mutually close epicentres were investigated (Zakynthos, Western Greece, April 2006, magnitudes ∼5.5) and a strong non‐double‐couple component of one of them was identified (double‐couple percentage of about 20%). Two equivalent models of this earthquake were found: a single‐event non‐ double‐couple model, and a double‐event model consisting of two double‐couple sources with highly different mechanisms.
Improved Monte Carlo inversion of surface wave data
Authors: Socco Laura Valentina , Boiero Daniele 
Published: April 2008

ABSTRACTInversion of surface wave data suffers from solution non‐uniqueness and is hence strongly biased by the initial model. The Monte Carlo approach can handle this non‐uniqueness by evidencing the local minima but it is inefficient for high dimensionality problems and makes use of subjective criteria, such as misfit thresholds, to interpret the results. If a smart sampling of the model parameter space, which exploits scale properties of the modal curves, is introduced the method becomes more efficient and with respect to traditional global search methods it avoids the subjective use of control parameters that are barely related to the physical problem. The results are interpreted drawing inference by means of a statistical test that selects an ensemble of feasible shear wave velocity models according to data quality and model parameterization. Tests on synthetic data demonstrate that the application of scale properties concentrates the sampling of model parameter space in high probability density zones and makes it poorly sensitive to the initial boundary of the model parameters. Tests on synthetic and field data, where boreholes are available, prove that the statistical test selects final results that are consistent with the true model and which are sensitive to data quality. The implemented strategies make the Monte Carlo inversion efficient for practical applications and able to effectively retrieve subsoil models even in complex and challenging situations such as velocity inversions.
Cross‐correlation of random fields: mathematical approach and applications
Authors: Gouédard P. , Stehly L. , Brenguier F. , Campillo M. , Colin de Verdière Y. , Larose E. , Margerin L. , Roux P. , Sánchez‐Sesma F. J. , Shapiro N. M. , Weaver R. L. 
Published: April 2008

ABSTRACTRandom field cross‐correlation is a new promising technique for seismic exploration, as it bypasses shortcomings of usual active methods. Seismic noise can be considered as a reproducible, stationary in time, natural source. In the present paper we show why and how cross‐correlation of noise records can be used for geophysical imaging. We discuss the theoretical conditions required to observe the emergence of the Green's functions between two receivers from the cross‐correlation of noise records. We present examples of seismic imaging using reconstructed surface waves from regional to local scales. We also show an application using body waves extracted from records of a small‐scale network. We then introduce a new way to achieve surface wave seismic experiments using cross‐correlation of unsynchronized sources. At a laboratory scale, we demonstrate that body wave extraction may also be used to image buried scatterers. These works show the feasibility of passive imaging from noise cross‐correlation at different scales.
Seismic and electromagnetic controlled‐source interferometry in dissipative media
Authors: Wapenaar Kees , Slob Evert , Snieder Roel 
Published: April 2008

ABSTRACTSeismic interferometry deals with the generation of new seismic responses by crosscorrelating existing ones. One of the main assumptions underlying most interferometry methods is that the medium is lossless. We develop an ‘interferometry‐by‐deconvolution’ approach which circumvents this assumption. The proposed method applies not only to seismic waves, but to any type of diffusion and/or wave field in a dissipative medium. This opens the way to applying interferometry to controlled‐source electromagnetic (CSEM) data. Interferometry‐by‐deconvolution replaces the overburden by a homogeneous half space, thereby solving the shallow sea problem for CSEM applications. We demonstrate this at the hand of numerically modeled CSEM data.
Seismic reflection coefficients of faults at low frequencies: a model study
Authors: Van Der Neut Joost , Sen Mrinal K. , Wapenaar Kees 
Published: April 2008

ABSTRACTWe use linear slip theory to evaluate seismic reflections at non‐welded interfaces, such as faults or fractures, sandwiched between general anisotropic media and show that at low frequencies the real parts of the reflection coefficients can be approximated by the responses of equivalent welded interfaces, whereas the imaginary parts can be related directly to the interface compliances. The imaginary parts of low frequency seismic reflection coefficients at fault zones can be used to estimate the interface compliances, which can be related to fault properties upon using a fault model. At normal incidence the expressions uncouple and the complex‐valued P‐wave reflection coefficient can be related linearly to the normal compliance. As the normal compliance is highly sensitive to the infill of the interface, it can be used for gas/fluid identification in the fault plane. Alternatively, the tangential compliance of a fault can be estimated from the complex‐valued S‐wave reflection coefficient. The tangential compliance can provide information on the crack density in a fault zone. Coupling compliances can be identified and quantified by the observation of PS conversion at normal incidence, with a comparable linear relationship.
Increased pancreatic islet mass is accompanied by activation of the insulin receptor substrate‐2/serine‐threonine kinase pathway and augmented cyclin D2 protein levels in insulin‐resistant rats
Authors: Rafacho Alex , Ribeiro Daniele Lisboa , Boschero Antonio Carlos , Taboga Sebastião Roberto , Bosqueiro José Roberto 
Published: April 2008

SummaryIt is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta‐cell function and proliferation, in islets from insulin‐resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7‐fold in islet mass and of 1.6‐fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta‐cell proliferation, evaluated at the immunohistochemical level using anti‐PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta‐cell proliferation of 6.4‐fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate‐2 (IRS‐2), phosphorylated‐serine‐threonine kinase AKT (p‐AKT), cyclin D2 and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta‐cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS‐2/AKT pathway and activation of the cell cycle, mediated by cyclin D2. These adaptations permit the maintenance of glycaemia at near‐physiological ranges.
Modelling wildlife–human relationships for social species with mixed‐effects resource selection models
Authors: Hebblewhite Mark , Merrill Evelyn 
Published: April 2008

Summary

Resource selection functions (RSF) have contributed to the conservation of species negatively affected by human activities. Despite these applications, two assumptions frequent many studies: the assumption of independence among groups in social species, and that selection is proportional to resource availability. This latter case is known as a functional response in resource selection, and may be especially important in human–wildlife relationships where there is a fitness cost of proximity to humans.
Recent advances in generalized linear mixed models offer new ways to account for resource selection in social species and functional responses by accommodating correlations within hierarchical groups with random intercepts, and functional responses with random coefficients.
We illustrate the application of mixed‐effects RSF models using a case study of resource selection by individual wolves Canis lupus living in packs as a function of human activity.
In areas of low human activity, wolf resource selection was independent of proximity to humans. As human activity increased, wolves displayed a functional response selecting areas closer to human activity. With increasing human activity, however, wolves displayed spatio‐temporal avoidance of human activity during daylight. This could lead to behaviourally induced trophic cascades mediated by wolf avoidance of human activity, and fits within the framework of attractive sink habitats.
Accounting for the hierarchical social structure of wolves clearly showed that the response of wolves to human disturbance was strongly correlated, but different, within packs, and that the correlation was strongest during winter and weakest during summer.
Syntheses and applications. Failure to consider the social structure of wolves and the functional response to human activity would result in mistaken conclusions about wolf–human relationships. Our approach provides a unifying framework to understand the contradictory results of previous studies of wolf–human relationships and a template for future studies to evaluate effects of increasing human activity on wildlife.
Intensive care unit staff nurses: predicting factors for career decisions
Authors: Lai Hui‐Ling , Lin Ya‐Ping , Chang Hui‐Kuan , Wang Shu‐Chen , Liu Yun‐Ling , Lee Huei‐Chen , Peng Tai‐Chu , Chang Fwu‐Mei 
Published: April 2008

Aims and Objectives.  The aim of this study was to understand the factors related to intention to leave their job among intensive care unit (ICU) nurses in eastern Taiwan and to make between‐group comparisons between an intention to leave and an intention to stay as well as to predict the influencing factors that affect ICU staff nurses’ intention to leave.Background.  Nurses’ intention to leave their job may have an important impact on the actual turnover of nurses. The issue has always been of concern to nursing executives. Only limited empirical studies in the area have been investigated in an Asian culture context and particularly the eastern Taiwan region.Methods.  A cross‐sectional predictive study was performed during 2005 with 130 nurses recruited from two ICUs at a medical centre. A researcher‐designed questionnaire based on the Cooper's model with structured interviews was used to determine each nurse's characteristics and their intention to leave their job. Multiple logistic regression analysis was employed to investigate the various factors associated with this.Results.  The overall response rate was 100%; 63 (48·9%) revealed that they intended to leave their jobs. The findings were that their self‐rated health status, the number of diseases, the level of happiness, the presence of depression, job satisfaction, sleep quality, type of license and their unit were significantly associated with an intention to leave (p = 0·05–0·001). Depression and sleep quality proved to be the most significant predictors of ICU staff nurses’ intention to leave their job.Conclusions.  The findings suggest that there is a need to take steps to improve nurses’ health‐related quality of life and to develop effective strategies to improve nurse retention.Relevance to clinical practice.  A succinct validated instrument would help identify the important factors that predict ICU nurses’ intention to leave their job, which may result in job disengagement. Predictors found in this study may be used as outcome variables for developing such an effective method of improving nurse retention in ICUs.
The global, ppGpp‐mediated stringent response to amino acid starvation in Escherichia coli
Authors: Traxler Matthew F. , Summers Sean M. , Nguyen Huyen‐Tran , Zacharia Vineetha M. , Hightower G. Aaron , Smith Joel T. , Conway Tyrrell 
Published: April 2008

SummaryThe stringent response to amino acid starvation, whereby stable RNA synthesis is curtailed in favour of transcription of amino acid biosynthetic genes, is controlled by the alarmone ppGpp. To elucidate the extent of gene expression effected by ppGpp, we designed an experimental system based on starvation for isoleucine, which could be applied to both wild‐type Escherichia coli and the multiauxotrophic relA spoT mutant (ppGpp0). We used microarrays to profile the response to amino acid starvation in both strains. The wild‐type response included induction of the general stress response, downregulation of genes involved in production of macromolecular structures and comprehensive restructuring of metabolic gene expression, but not induction of amino acid biosynthesis genes en masse. This restructuring of metabolism was confirmed using kinetic Biolog assays. These responses were profoundly altered in the ppGpp0 strain. Furthermore, upon isoleucine starvation, the ppGpp0 strain exhibited a larger cell size and continued growth, ultimately producing 50% more biomass than the wild‐type, despite producing a similar amount of protein. This mutant phenotype correlated with aberrant gene expression in diverse processes, including DNA replication, cell division, and fatty acid and membrane biosynthesis. We present a model that expands and functionally integrates the ppGpp‐mediated stringent response to include control of virtually all macromolecular synthesis and intermediary metabolism.