bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extended survival of Puccinia graminis f. sp. tritici urediniospores: implications for biosecurity and on‐farm management
Authors: Barua P. , You M. P. , Bayliss K. L. , Lanoiselet V. , Barbetti M. J. 
Published: October 2017

Puccinia graminis f. sp. tritici (Pgt), the causal organism of stem rust, is of global importance across wheat‐growing countries. However, some epidemics commence without the obvious presence of ‘alternate’ or ‘green bridge’ hosts, suggesting urediniospores can survive in the absence of suitable host plants for many weeks. Testing a range of inert material types, including metals, plastics, fabrics and woods, highlighted a significant effect of material type and temperature on urediniospore viability (P < 0.001), with urediniospores remaining attached and viable on these materials (aluminium, paper, rubber, all fabric and all woods) for up to 365 days at 23/8 °C day/night. At 36/14 °C day/night, urediniospore viability was retained for a maximum of 300 days on denim and jute. Furthermore, at 45/15 °C day/night, urediniospores remained viable for a maximum of 180 days on cotton and jute. The frequency of recovery of attached urediniospores was also dependent upon the material type, with significant differences between materials in their abilities to retain urediniospores after washing (P < 0.001). Urediniospores recovered even after 300 or 365 days from the lower two temperature regimes successfully initiated infections of wheat seedlings. Results confirm the potential importance of inert materials as long‐term carriers of viable Pgt urediniospores, highlighting risks of spread of new pathotypes and strains across wheat‐growing regions, the significant biosecurity implications for contaminated carrier materials, and its likely survival across seasons without a host.
A molecular phylogeny of East African Amytta (Orthoptera: Tettigoniidae, Meconematinae) with data on their cytogenetics
Authors: HEMP CLAUDIA , HELLER KLAUS‐GERHARD , WARCHAŁOWSKA‐ŚLIWA ELŻBIETA , GRZYWACZ BEATA 
Published: October 2017

AbstractThis is the first study to address the molecular phylogeny of East African Meconematinae. We used DNA sequence data from the three genes cytochrome oxidase subunit I (COI), 16S rRNA and histone H3 to reconstruct the relationships within the genus Amytta using Bayesian Inference and maximum likelihood. We included 45 individuals representing 19 Meconematinae taxa from Africa, Europe and Australia, and three outgroup species to explore taxonomic limits at different levels. Members of the genus Amytta belong to three related lineages within Meconematinae. Species of Amytta were found to be monophyletic with Meconema and Phlugidia as sister groups. The molecular results are in accordance with previous morphological and ecological studies. Chromosome numbers and the type of sex determination systems found in Amytta agrees with the three lineages also found in the phylogenetic tree. We conclude that the radiation of Amytta species is geological young. Biogeographical patterns caused by climatic fluctuations of the past seen also in other nonrelated Orthoptera taxa such as the coptacrine genus Parepistaurus are the drivers of biodiversity in the area.
Largely additive effects of gibberellin and strigolactone on gene expression in Arabidopsis thaliana seedlings
Authors: Lantzouni Ourania , Klermund Carina , Schwechheimer Claus 
Published: October 2017

SummaryThe phytohormones gibberellin (GA) and strigolactone (SL) are involved in essential processes in plant development. Both GA and SL signal transduction mechanisms employ α/β‐hydrolase‐derived receptors that confer E3 ubiquitin ligase‐mediated protein degradation processes. This suggests a common evolutionary origin of these pathways and possibly a molecular interaction between them. One such indication stems from rice, where the DELLA protein of the GA pathway was reported to interact with the SL receptor. Here, we examine the physiological interaction between both pathways through the analysis of GA (ga1) and SL biosynthesis (max1 and max3) mutants. In ga1 max double mutants, we find indications only for additive interactions when examining several phenotypic readouts. We further identify short‐term transcriptional responses to GA and the synthetic SL rac‐GR24 through next‐generation sequencing of poly‐adenylated RNAs (RNA‐seq) in ga1 max1. Remarkably, both hormones lead to predominantly additive transcriptional changes of a largely overlapping set of genes. The expression of only a few genes was altered in a synergistic manner but, interestingly, these include the genes encoding the GA catabolic enzyme GA2 OXIDASE2 (GA2ox2) as well as the SL pathway regulators BRANCHED1 (BRC1) and SUPPRESSOR OF max2 1‐LIKE8 (SMXL8). We conclude that GA and rac‐GR24 signaling in Arabidopsis seedlings converge at the level of transcription of a common gene‐set.
Multifaceted plant responses to circumvent Phe hyperaccumulation by downregulation of flux through the shikimate pathway and by vacuolar Phe sequestration
Authors: Lynch Joseph H. , Orlova Irina , Zhao Chengsong , Guo Longyun , Jaini Rohit , Maeda Hiroshi , Akhtar Tariq , Cruz‐Lebron Junellie , Rhodes David , Morgan John , Pilot Guillaume , Pichersky Eran , Dudareva Natalia 
Published: October 2017

SummaryDetrimental effects of hyperaccumulation of the aromatic amino acid phenylalanine (Phe) in animals, known as phenylketonuria, are mitigated by excretion of Phe derivatives; however, how plants endure Phe accumulating conditions in the absence of an excretion system is currently unknown. To achieve Phe hyperaccumulation in a plant system, we simultaneously decreased in petunia flowers expression of all three Phe ammonia lyase (PAL) isoforms that catalyze the non‐oxidative deamination of Phe to trans‐cinnamic acid, the committed step for the major pathway of Phe metabolism. A total decrease in PAL activity by 81–94% led to an 18‐fold expansion of the internal Phe pool. Phe accumulation had multifaceted intercompartmental effects on aromatic amino acid metabolism. It resulted in a decrease in the overall flux through the shikimate pathway, and a redirection of carbon flux toward the shikimate‐derived aromatic amino acids tyrosine and tryptophan. Accumulation of Phe did not lead to an increase in flux toward phenylacetaldehyde, for which Phe is a direct precursor. Metabolic flux analysis revealed this to be due to the presence of a distinct metabolically inactive pool of Phe, likely localized in the vacuole. We have identified a vacuolar cationic amino acid transporter (PhCAT2) that contributes to sequestering excess of Phe in the vacuole. In vitro assays confirmed PhCAT2 can transport Phe, and decreased PhCAT2 expression in PAL‐RNAi transgenic plants resulted in 1.6‐fold increase in phenylacetaldehyde emission. These results demonstrate mechanisms by which plants maintain intercompartmental aromatic amino acid homeostasis, and provide critical insight for future phenylpropanoid metabolic engineering strategies.
Moonpool Behavior of a Stationary Vessel in Waves and a Method to Increase Operability
Authors: Chalkias Dimitris , Krijger Jan-Willem 
Published: October 2017

Potential flow frequency domain calculations have been performed to predict the natural frequencies and water motions for several moonpools. The moonpool free surface has been replaced by a damping lid in WAMIT without changing the kinematic free surface condition. Instead, the free surface modes of motion have been modeled as generalized modes. In this way, different damping values per mode can be applied. Damping values have been calculated based on CFD free decay tests and validated with model tests.
Two vessels were chosen for this study with different moonpool dimensions and shapes. The first is a construction vessel with a small rectangular moonpool, whereas the second is a drillship featuring a large moonpool optimized for transit. Free decay CFD calculations have been performed for both vessels, while CFD regular wave calculations have been performed for the construction vessel and model tests were performed for the drillship.
Using the aforementioned methodology, a motion reduction device is designed and presented in this paper. The aim of this device is to reduce the motions experienced in the moonpool during vessel operations in a sea state and thus to increase the operability of the vessel with respect to moonpool motion limitations.
The increased vessel operability with the new device is shown by a wave scatter analysis. In order to calculate the workability limit curves, suitable limits have been chosen for the free surface elevation and the water vertical velocity in the moonpool.
Motion Characteristic Analysis of a Floating Structure in the South China Sea Based on Prototype Monitoring
Authors: Wu Wen-hua , Cui Xiao-wei , Lv Bai-cheng , Wang Shi-sheng , Feng Jia-guo , Yue Qian-jin 
Published: October 2017

Background: Due to the complexity of ocean environmental loading models, together with the nonlinearity and empirical parameters involved in hydrodynamic numerical modeling and model testing, many uncertainties and challenges still exist in the design and operation of platforms built to float at sea. On-site prototype measurements carried out on actual floating structures provide a valid strategy for obtaining accurate environmental loading parameters and floater motion responses.
Problem definition: A prototype monitoring system has been built as part of a joint industrial project in the South China Sea. A complete set of long-term ocean environment loading parameters and structural dynamic motion responses has been gathered for the period from 2012 to the present. Several advanced techniques, such as the independent remote monitoring technique (IRMT), the integrated continuous measurement technique and the standalone underwater measurement technique were established to enhance the reliability of data collection even during extreme typhoon conditions when there was no power.
Solution approach and findings: this paper analyzes the dynamic motion characteristics of the platform structure based on the monitoring data. The relationship between the measured wave spectrum and the JONSWAP spectrum is discussed. The spectral shape parameters of the JONSWAP spectrum for the South China Sea, as derived from the monitoring data, are discussed. The dynamic motions of the platform structure are analyzed based on artificial neural networks (ANN) using data from a typical monitored typhoon. The numerical modeling used in this research is constructed to perform the identification analysis of the platform parameters using radius basic function (RBF) and hydrodynamic results produced by ANSYS-AQWA. This research selects five main geometric parameters related to the platform design. Mass, moments of inertia of three rotation degrees, and the position of the center of gravity (COG) are selected as the optimization objectives. The mean values of surge and pitch and standard deviations of roll and pitch are treated as the input parameters. Modeling verifications show that the present ANN-based method performs well in obtaining the optimal platform parameters. The maximum error between the simulated and monitored results in terms of the measurement of the roll, pitch, surge and sway motions fall within 5%. The model of the monitored platform could be further updated; it could be made capable of performing the performance assessments of the dynamic characteristics in extreme and/or harsh environmental conditions.
Estimating Hydrodynamic Sectional Loads for FPSOs Using Artificial Neural Networks
Authors: Engebretsen Espen , Shu Zhi , Borgen Jon Erik 
Published: October 2017

Sizing of a new build FPSO hull is an iterative optimization process, where the main dimensions of the FPSO are varied until the optimal size is found, within a defined input domain. A wide range of criteria should be evaluated per size iteration, and thus the sizing process may be a very time consuming task. In order to speed up this process, it may be beneficial to adopt an automated iterative algorithm for performing the sizing of new build FPSOs for the Concept and Front-End Engineering Design (FEED) phase.
The hull steel weight should be calculated for each size iteration, thus the hydrodynamic bending moment and shear force are needed. Obtaining the hydrodynamic sectional loads requires relatively time consuming calculations (compared to e.g. the required hydrostatic calculation), such as linear diffraction/radiation analysis and stochastic postprocessing. The required computational time of the automated sizing algorithm can be significantly reduced by calculating the hydrodynamic sectional loads by a simplified estimator, eliminating the need for e.g. diffraction/radiation analysis. Such an estimator may be obtained by the use of Artificial Neural Networks (ANNs).
This paper presents how to estimate the hydrodynamic vertical bending moment and shear force for FPSOs, within acceptable accuracy to be used for initial sizing, using ANNs. The estimators, i.e. the ANNs, take known inputs such as the main dimensions, draft and pitch radius of gyration of the FPSO. The ANNs are trained on a database containing linear diffraction/radiation analyses for a variety of FPSO main dimensions, hull shapes and loading conditions.
The database has been established by batch processing of the DNV-GL software HydroD [1], Wadam [2] and Postresp [3] through MATLAB [4]. This paper presents the methods used to obtain the results contained in the database, as well as training and performance of the ANNs.
Reliability Analysis of Offshore Structures Using OMA Based Fatigue Stresses
Authors: Nabuco Bruna , Tarpø Marius , Aïssani Amina , Brincker Rune 
Published: October 2017

Today, many offshore structures in the North Sea already reached their predicted lifetime. Since it is still required a huge demand of oil, it results in an important need to keep those structures in operation. The great attention concerning the lifetime of offshore platforms has trigged a need for monitoring these structures in order to gain information about their actual state and hence reduce the uncertainty and allow for more optimal decision planning regarding maintenance, repair and future inspection actions.
Throughout the lifetime, the performance of the structure can be evaluated by analyzing the deterioration process of the structure. In the offshore environment, one of the most common deterioration mechanisms is the fatigue of structural steel induced by wave loading. The deterioration formulation of a structural system subjected to fatigue is nowadays well known. However, many uncertainties may affect the accuracy of the performance evaluation. It can be mentioned mainly the uncertainties related to the materials, the uncertainty on Miner’s rule and the uncertainty on the SN curve but most importantly is the uncertainty on the stress ranges induced by the wave loading.
In this paper, the mainly focus is on the uncertainty observed on the different stresses used to predict the damage. This uncertainty can be reduced by Modal Based Fatigue Monitoring which is a technique based on continuously measuring of the accelerations in few points of the structure with the use of accelerometers known as reliable for long time measurements. An Operational Modal Analysis (OMA) is performed and then a modal filtering of the operating response is considered, so that the modal coordinates of all significant modes are known. Next, the experimental mode shapes are expanded using a Finite Element (FE) model together with the Local Correspondence (LC) principle and the displacements can be estimated in all degrees of freedom of the FE model, allowing the stresses and strains to be obtained from the element equations. It is important to emphasize that even though the accelerations are measured in only a few points of the structure, the stress history can be calculated in any arbitrary point of the structure.
The accuracy of the estimated actual stress is analyzed by experimental tests on a scale model where the obtained stresses are compared to strain gauges measurements. After evaluating the fatigue stresses directly from the operational response of the structure, a reliability analysis is performed in order to estimate the reliability of using Modal Based Fatigue Monitoring for long term fatigue studies.
VIV Responses of Riser With Buoyancy Elements: Forced Motion Test and Numerical Prediction
Authors: Wu Jie , Lie Halvor , Fu ShiXiao , Baarholm Rolf , Constantinides Yiannis 
Published: October 2017

Steel Lazy Wave Riser (SLWR) is an attractive deep water riser concept. When subjected to vortex induced vibrations (VIV), the vortex shedding process of the buoyancy element and the bare riser section will be different due to the difference in diameter. VIV responses can be strongly influenced by the dimension of the buoyancy element and its arrangement.
Empirical VIV prediction programs, such as VIVANA, SHEAR7 and VIVA, are widely used by the industry for design against VIV loads. However, there is lack of hydrodynamic data to be used in these programs when buoyancy elements are present.
Experiment to obtain hydrodynamic data for riser with staggered buoyancy elements was carried out in the towing tank in SINTEF Ocean. A rigid cylinder section with three staggered buoyancy elements was subjected to harmonic forced cross-flow (CF) motions. Hydrodynamic forces on one of the buoyancy elements were directly measured in addition to the measured forces at both ends of the test section. Two buoyancy element configurations were tested and the corresponding hydrodynamic data are compared with that of a bare cylinder. The obtained hydrodynamic data was also used in VIV prediction software and good prediction against existing flexible cylinder staggered buoyancy element VIV test data was achieved. A roadmap to achieve an optimal SLWR design by combining different experimental and numerical methods is suggested.
Column Slamming Loads on a TLP From Steep and Breaking Waves
Authors: Vestbøstad Tone M. , Økland Ole David , Lian Gunnar , Stavang Terje Peder 
Published: October 2017

Previous model test campaigns of various large-volume platforms indicate that wave impact loads on vertical platform columns can become high in extreme sea states. Column slamming is a highly non-linear and complex problem and reliable estimation1 of Ultimate Limit State (ULS) and Accidental Limit State (ALS) design loads is a challenge. Previous measurements indicate ALS pressures of about 3 MPa acting on an area of typically 50m2 in North Sea and Norwegian Sea wave conditions. The corresponding ULS loads were in the range 1.5–2.0 MPa for the same impact area. Such high predictions for ULS and ALS impact pressures may be critical for both steel and concrete platforms, and accurate predictions of design loads is therefore crucial to establish the correct level of safety.
A model test campaign dedicated to investigate column slamming has been performed on the Heidrun platform, a large concrete Tension Leg Platform (TLP). The column diameter is 31 m. The test campaign was performed in 2013 at Marintek (now Sintef Ocean), at a model scale of 1:55. The main objective of the test campaign was to estimate the characteristic slamming loads, defined as the q-annual extreme 3-hour slamming load level of 10−2 for the Ultimate Limit State (ULS) and 10−4 for the Accidental Limit State (ALS).
To ascertain that the test campaign would result in reliable load estimates, a pre-study on column slamming was performed, involving a selected expert group with participants from several organizations. Review of previous work, identification of governing parameters for wave impact and assessment of model uncertainties and extreme value prediction of slamming loads was performed. It was concluded that two challenges were to be specifically addressed during the planning and execution of the test: 1) the localized nature and short duration of the slamming loads and 2) the large statistical variability of the slamming loads. To address the first challenge, special focus was given to the extent and quality of the instrumentation capturing the slamming loads. Comprehensive documentation of the instrumentation was also performed using hammer testing, structural analysis and drop tests. The second challenge was addressed with a carefully planned test strategy. The resulting model test campaign set a new standard for model testing of such loads, using over 80 slamming panels with a sampling frequency of 19.2 kHz, and over 300 sea state realizations.
This paper presents the planning and execution of the model test campaign, including the instrumentation and model set-up, the test matrix, main challenges, findings and results.
Investigations Into Fatigue Performance of Offshore Mooring Chains
Authors: Farrow Gary H. , Potts Andrew E. , Washington Daniel G. 
Published: October 2017

The Chain Finite Element Analysis of Residual Strength Joint Industry Project (Chain FEARS JIP) aimed to develop guidance for the determination of a rational discard criteria for mooring chains subject to severe pitting corrosion which would otherwise require immediate removal and replacement.
Critical to the ability to evaluate the residual fatigue life of a degraded chain, is to have an accurate estimate of the chain in its as-new condition, thereby providing a benchmark for any loss in fatigue life associated with severe corrosion or wear. A non-linear multi-axial Finite Element Analysis (FEA) fatigue assessment method was developed and correlated against available fatigue test data as part of the JIP achieving this critical requirement.
The development of this correlated methodology necessitated a review of:
• The available mooring chain fatigue test data, to identify the factors influencing chain fatigue life and failure location.
• FEA fatigue methodologies currently employed in the industry.
• Current Class Rules relating to fatigue estimation.
• The influence of material, manufacturing and operational factors on chain fatigue life.
It was established that while the linear FEA fatigue method currently employed in the industry does not correlate with the fatigue test data, the non-linear multi-axial FEA fatigue method developed in the JIP afforded good correlation with test data.
It was also demonstrated that the magnitude of mean chain tension and inconsistency in proof loading, as a consequence of the inconsistency in Class Minimum Break Load (MBL) specification, and with respect to chain size and the varying material ductility of steel grades, effects fatigue life.
The identified inconsistency in the proofing indicates a likely inconsistency in conservatism embodied in the Class Rules fatigue formulation. Consequently it is possible that chains of certain size and grade may have significantly less fatigue life than anticipated by Class.
Further work is recommended to establish a more rational proof load specification and to develop an alternative Class Rules fatigue formulation accounting for the identified factors influencing fatigue.