bluuebunny/crossref_metadata_2025_split huggingface dataset:
Holocene re‐colonisation, central–marginal distribution and habitat specialisation shape population genetic patterns within an Atlantic European grass species
Authors: Harter D. E. V. , Jentsch A. , Durka W. 
Published: September 2014

AbstractCorynephorus canescens (L.) P.Beauv. is an outbreeding, short‐lived and wind‐dispersed grass species, highly specialised on scattered and disturbance‐dependent habitats of open sandy sites. Its distribution ranges from the Iberian Peninsula over Atlantic regions of Western and Central Europe, but excludes the two other classical European glacial refuge regions on the Apennine and Balkan Peninsulas. To investigate genetic patterns of this uncommon combination of ecological and biogeographic species characteristics, we analysed AFLP variation among 49 populations throughout the European distribution range, expecting (i) patterns of SW European glacial refugia and post‐glacial expansion to the NE; (ii) decreasing genetic diversity from central to marginal populations; and (iii) interacting effects of high gene flow and disturbance‐driven genetic drift. Decreasing genetic diversity from SW to NE and distinct gene pool clustering imply refugia on the Iberian Peninsula and in western France, from where range expansion originated towards the NE. High genetic diversity within and moderate genetic differentiation among populations, and a significant pattern of isolation‐by‐distance indicate a gene flow drift equilibrium within C. canescens, probably due to its restriction to scattered and dynamic habitats and limited dispersal distances. These features, as well as the re‐colonisation history, were found to affect genetic diversity gradients from central to marginal populations. Our study emphasises the need for including the specific ecology into analyses of species (re–)colonisation histories and range centre–margin analyses. To account for discontinuous distributions, new indices of marginality were tested for their suitability in studies of centre–periphery gradients.
The Impact of Arteriovenous Fistulae on the Myocardium: The Impact of Creation and Ligation in the Transplant Era
Authors: Duque Juan Camilo , Gomez Camilo , Tabbara Marwan , Alfonso Carlos E. , Li Xiaoyi , Vazquez‐Padron Roberto I. , Asif Arif , Lenz Oliver , Briones Patricia L. , Salman Loay H. 
Published: September 2014

AbstractCardiac hypertrophy is a relatively common complication seen in patients with advanced chronic kidney disease (CKD) and end‐stage renal disease (ESRD). Moreover, cardiac hypertrophy is even more frequently seen in patients with ESRD who have an arteriovenous (AV) access. There has been substantial evidence pertaining to the effects of AV access creation on the heart structure and function. Similarly, there is increasing evidence on the effects of AV access closure, flow reduction, transplantation, and immunosuppressive medication on both endpoints. In this review, we present the evidence available in the literature on these topics and open the dialog for further research in this interesting field.
Deciphering the roles of Arabidopsis LPCAT and PAH in phosphatidylcholine homeostasis and pathway coordination for chloroplast lipid synthesis
Authors: Wang Liping , Kazachkov Michael , Shen Wenyun , Bai Mei , Wu Hong , Zou Jitao 
Published: September 2014

SummaryPhosphatidylcholine (PC) is a key intermediate in the metabolic network of glycerolipid biosynthesis. Lysophosphatidylcholine acyltransferase (LPCAT) and phosphatidic acid phosphatase (PAH) are two key enzymes of PC homeostasis. We report that LPCAT activity is markedly induced in the Arabidopsis pah mutant. The quadruple pah lpcat mutant, with dual defects in PAH and LPCAT, had a level of lysophosphatidylcholine (LPC) that was much higher than that in the lpcat mutants and a PC content that was higher than that in the pah mutant. Comparative molecular profile analysis of monogalactosyldiacylglycerol and digalactosyldiacylglycerol revealed that both the pah and pah lpcat mutants had increased proportions of 34:6 from the prokaryotic pathway despite differing levels of LPCAT activity. We show that a decreased representation of the C16:0C18:2 diacylglycerol moiety in PC was a shared feature of pah and pah lpcat, and that this change in PC metabolic profile correlated with the increased prokaryotic contribution to chloroplast lipid synthesis. We detected increased PC deacylation in the pah lpcat mutant that was attributable at least in part to the induced phospholipases. Increased LPC generation was also evident in the pah mutant, but the phospholipases were not induced, raising the possibility that PC deacylation is mediated by the reverse reaction of LPCAT. We discuss possible roles of LPCAT and PAH in PC turnover that impacts lipid pathway coordination for chloroplast lipid synthesis.
Improving the accuracy of the preoperative diagnosis of long head of the biceps pathology: the biceps resisted flexion test
Authors: Arrigoni Paolo , Ragone Vincenza , D’Ambrosi Riccardo , Denard Patrick , Randelli Filippo , Banfi Giuseppe , Cabitza Paolo , Randelli Pietro 
Published: September 2014

Purpose: the purpose of this study was to describe a new test for identifying lesions of the long head of the biceps (LHB) and to evaluate its diagnostic performance in comparison with selected traditional clinical tests.
Methods: one hundred and nine consecutive candidates for arthroscopic rotator cuff repair were prospectively recruited.The BRF test, which measures biceps resisted flexion strength, was performed with the patient seated (armat the side and elbow flexed at 90°). The patient was asked to maintain maximal resistance for five seconds while strength was assessed with a digital dynamometer. Since the dynamometer expresses a continuous variable in kilograms, the measure was dichotomized using a threshold value (cut-off ) valueable to simultaneously maximize the sensitivity and specificity. This cut-off value was derived from receiver operating characteristic (ROC) curve analysis.Speed’s test and the O’Brien test were also performed. During arthroscopy the presence of LHB pathology was assessed.
Results: biceps resisted flexion strength was significantly higher in patients without associated LHB lesions [median (range): 3 kg (0-9.5 kg) versus 0 kg (0-8.5 kg); p< 0.001]. The cut-off level able to simultaneously maximize the sensitivity and specificity of the test was 1.1kg.The area under the ROC curve was 0.745 (p<0.001) for the dichotomic BRF test (dBRF), 0.562 (p=0.3) for the O’Brien test, and 0.602 (p=0.113) for Speed’s test. A significant good level of accuracy was achieved only by the dBRF test. Specificity and the positive predictive value were significantly higher for the dBRF test than for Speed’s and O’Brien’s tests (p<0.02). Age and the dBRF test were both found to be significant predictors of LHB lesions.
Conclusions: the dBRF test showed higher accuracy than traditional clinical tests in diagnosing LHB lesions. This novel test for biceps pathology may be advantageous because it is objective and therefore likely reproducible.
Level of Evidence: Level II, Development of diagnostic test on basis of consecutive patients (with universally applied reference “gold” standard).
Analysis of differences in bone removal during femoral box osteotomy for primary total knee arthroplasty
Authors: Graceffa Angelo , Indelli Pier , Basnett Kaitlyn , Marcucci Massimiliano 
Published: September 2014

Purpose: this study was conducted to compare the quantity of intercondylar bone removed during femoral box osteotomy for implantation of three contemporary posterior stabilized (PS) total knee arthroplasty designs: Sigma PS (DePuy), Vanguard (Biomet) and Persona (Zimmer).
Methods: we compared the maximum volumetric bone resection required for the housing of the PS mechanism of these three designs. Bone removal by each PS box cutting jig was three-dimensionally measured. The differences between the three designs were analyzed by the Kruskal-Wallis test. The Mann-Whitney U-test was used for pairwise comparisons. The level of significance was set at p<0.05.
Results: for small-size implants, the average box osteotomy volume of Persona was significantly smaller than the Vanguard and Sigma PS volumes (p=0.003). The mean difference between Vanguard and Sigma PS (p=0.01) was also significant. For medium size implants, the mean difference between Persona and Sigma PS (p=0.008) and the mean difference between Vanguard and Sigma PS (p=0.01) were statistically significant. For large size implants, the mean difference between Vanguard and Sigma PS (p=0.01) and the mean difference between Sigma PS and Persona (p=0.008) were statistically significant.
Conclusions: irrespective of implant size, the Persona cutting jig always resected significantly less bone than did Vanguard and Sigma PS.
Clinical Relevance: although this study does not establish any clinical relevance of removing more or less bone at primary TKA, its results suggest that if a PS design is indicated, it is preferable to select a model which resects less distal femoral bone.
The Effect of Coverage Length and Density on the Performance of Helical Strakes
Authors: Allen Don W. , Liapis Stergios 
Published: September 2014

When utilizing helical strakes, a critical decision is how much of the tubular to cover with helical strakes. While minimizing the cost of the helical strakes is one objective, often it is not possible to fully cover a tubular due to connectors, anodes, and other appurtenances. There are also important questions around ascertaining the performance of helical strakes when only a portion of the tubular is covered, for example when the top portion of a tubular is straked and the remainder is left bare.
This paper combines results from two testing programs on long cylinders towed at high Reynolds numbers to assess the performance of helical strakes with differing conditions along the cylinder length. The results show that the coverage length, density, and location of the helical strakes have a substantial effect on both the local and global response of the tubular.
An Advanced Thrust Allocation Algorithm for DP Applications, Taking Into Account Interaction Effects and Physical Limitations
Authors: Arditti F. , Cozijn J. L. , van Daalen E. F. G. 
Published: September 2014

The Dynamic Positioning (DP) system is responsible for the stationkeeping and manoeuvrability of a vessel in offshore operations. The forces required by the DP system are distributed among the available thrusters of the vessel by a thrust allocation algorithm, which should be both accurate — i.e. the sum of the effective forces is close to the required forces — and efficient — i.e. the total consumed power is minimal.
Ideally, the thrust allocation algorithm accounts for the forbidden zones, a practical solution to avoid significant hydrodynamic interaction effects such as thruster-hull interaction, thruster-current interaction and thruster-thruster interaction. Moreover, the thrust allocation algorithm should also take into account the physical limitations of each thruster such as the maximum thrust (saturation), the maximum rate of turn (azimuth) and the maximum rate of change of RPM.
In order to include these complex requirements in the thrust allocation algorithm the hydrodynamic interaction effects are modelled as efficiency functions, which are incorporated in the (power) object function and in the (required forces) constraints.
With the purpose of solving the complete problem, including the physical limitations and the hydrodynamic interaction effects, several advanced optimization methods were investigated. The selected optimization algorithms were the Sequential Quadratic Programming (SQP) method and the Steepest Descent (SD) method.
In this paper a DP drill ship is considered, with 6 azimuthing thrusters. Results were obtained for environmental conditions of increasing strength, from benign sea states to higher sea states with large required forces, eventually leading to thruster saturation. As a final test case, the required forces are such that the thrust allocation algorithm forces the thrusters to cross large forbidden zones with significant thruster-hull interaction.
The results show that the enhanced thrust allocation algorithm can deal with both hydrodynamic interaction effects and physical limitations in a time-efficient and robust manner. Altogether, these improvements are expected to lead to higher accuracy and efficiency for DP operations.
Study of Ice Failure and Deformation Processes
Authors: Aleksandrov Anatolii V. , Platonov Viktor V. , Matantsev Roman A. 
Published: September 2014

Intensive development of computer simulation technique for ice deformation and failure processes is an important problem in respect to both ice propulsion definition and strength analysis for ice vessel and ice-resistant structures. However, evaluation of applied algorithms effectiveness requires developing a procedure for verification of numerical models.
This paper presents results of experiment-calculated studies for strains in a bounded region on a specimen surface containing a point grid. Grid movement during the tests was recorded with the help of a system of three-dimensional computer vision and digital image correlation for noncontacting shape and deformation measurements. An experimental facility, test methodology, observed results and test results processing method are explained. Experimental data on freshwater field ice under uniaxial compression and bending are given.
Ice mechanical characteristics were evaluated based on inverse solution and finding ice strain characteristics as initial data for the finite element analysis. The calculated results were analyzed and compared with experimental data. Application of the proposed methodology will extend essentially a verification base for computer simulation of ice failure under contact with a structure and create prerequisites for forming a new direction in the area of ice numerical simulation.
Rankine Source Method for Seakeeping Analysis in Shallow Water
Authors: von Graefe Alexander 
Published: September 2014

Following Hachmann approach, Söding’s Rankine source method describes the steady perturbation potential in the body-fixed reference frame. This is beneficial for seakeeping predictions at forward speed, because error-prone m-terms do not occur in the boundary condition on the ship hull. Although similar terms arise in the boundary condition on the free surface, numerical inaccuracies in these terms have much less influence on the behaviour of the ship than in the traditional approach, where m-terms are evaluated on the hull. The periodic flow is linearised with respect to the amplitude of the incident wave, taking into account the steady ship wave.
A problem arises for shallow water problems if the Hachmann approach is used. For the shallow water problem, the boundary condition ‘no flow through the bottom’ must be fulfilled. Usually, this is done using image sources. If the steady perturbation potential is described in the body-fixed reference frame, this is not possible directly. This paper extends the Hachmann approach to treat this issue. Following the usual procedure for steady flow calculation, the boundary condition at the flat bottom of the steady problem is realised using image sources. For seakeeping computations, the steady perturbation potential is split into two parts, modelled respectively by steady sources above and below the flat bottom. The first part is assumed to be constant in the body-fixed reference frame, whereas the second part is assumed to be constant in the reference frame of the mirror image of the ship. This extended Hachmann approach fulfils the boundary condition at the flat bottom analytically.
Computed ship motions with and without forward speed in shallow water are validated by model test results from Flanders Hydraulics Research, Antwerp, and from TU Berlin.
Model Test of the STC Concept in Survival Modes
Authors: Wan Ling , Gao Zhen , Moan Torgeir 
Published: September 2014

The STC (Spar Torus Combination) concept combines a Spar floating wind turbine and a torus-shaped heaving-body wave energy converter (WEC). Numerical simulation has shown positive synergy between the WEC and the Spar floating wind turbine in operational conditions. However, in extreme wind and wave conditions, it is challenging to maintain structural integrity, especially for the WEC. To ensure survivability of this concept in extreme conditions, three survival modes have been proposed.
To investigate the performance of the STC in extreme conditions, model tests with a scale factor of 1:50 were carried out in the towing tank of MARINTEK, Norway. Two survival modes were tested. In both modes, the Torus WEC was fixed to the Spar. In the first mode, the Torus WEC is at the mean water surface, while in the second mode, the Torus WEC is fully submerged to a specified position. In the tests, 6 D.O.F rigid body motions, mooring line tensions, forces in 3 directions (X, Y and Z) between the Spar and Torus were measured, wind velocity and wind force were also measured by a sensor in front of the model and a load cell installed on the wind disc.
In this paper, the model test set-up for the two survival modes are described, and then decay tests, regular wave tests and the statistical tests for wind only, irregular wave only and irregular wave plus wind are presented, compared and analyzed. In the mean water level survival mode, the Torus had a small draft and large water plane area, so slamming and green water were observed as expected. In addition, Mathieu instability phenomena were observed during the regular wave test. In some large wave conditions in the fully submerged mode, no severe wave load occurred. All the results are presented in model scale unless specified, for direct comparison with numerical simulations later.
Comparison of Model Tests and Coupled Simulations for a Semi-Submersible Floating Wind Turbine
Authors: Huijs Fons , de Ridder Erik-Jan , Savenije Feike 
Published: September 2014

The GustoMSC Tri-Floater is a slender and robust three-column semi-submersible supporting an offshore wind turbine. Model tests were performed for a Tri-Floater equipped with an operational wind turbine and mooring system exposed to wind and waves in the offshore basin at MARIN. A high quality wind setup and special low Reynolds number blades were used, aiming at delivering the Froude scaled thrust. The base scope of experiments was performed with fixed blade pitch angle and generator speed. Some of the experiments were repeated with active blade pitch and generator torque control using a dedicated algorithm developed by ECN. The experiments covered typical operational and survival design conditions. Numerical simulations for the same wave and wind conditions were performed using ANSYS-AQWA coupled with PHATAS. The paper describes the setup and results of both the model tests and the simulations.
From the comparison of the numerical and experimental results, it is concluded that coupled aero-hydro-servo-elastic simulations can be used to predict the response of the floating offshore wind turbine to a sufficiently accurate level for design purposes. Furthermore, it is shown that the Tri-Floater motion response is very favorable and that the nacelle accelerations, air gap and mooring loads comply with the design requirements.
Assessing Conductor and Casing Systems for Damage From Extreme Snag Loads
Authors: Arikan Yusuf , Koska Ryan , Zlokich Jess 
Published: September 2014

Conductor and casing systems for subsea wells can be damaged due to excessive loads caused by vessel drift offs and snag loads. These types of accidental loads on the conductor and casing system are uncontrolled in nature and hence difficult to predict. Therefore, designing the system for these types of loads can be very challenging and economically not practical. Additionally, in the event of an incident subsea, a conductor and casing system is permanently installed and cannot readily be retrieved or inspected once the damage is done.
The decision to abandon or to produce from a well with a damaged conductor has serious financial and environmental consequences and should be fully understood. Therefore, to make a knowledgeable decision, it is necessary to understand extent of the damage and its implications for future operations by forensic analytical tools. This paper examines the methodology of a conductor and casing system damage assessment in order to support more informed decisions and provides a case example for a typical deepwater subsea well undergone excessive accidental loading. The objective of the assessment is (1) to verify wellhead system integrity and (2) evaluate the effect of any future operations on the integrity of the system. The paper outlines a process, suggested code checks, and analysis techniques which can be implemented to determine fitness for service of an excessively loaded wellhead system.
Plastic Mechanism Analysis of Structural Performance of Web Girders During Ship Collision and Grounding
Authors: Gao Zhenguo , Hu Zhiqiang 
Published: September 2014

The behavior of web girders is of crucial importance during ship collision and grounding accidents. A new theoretical deformation model for ship web girders subjected to in-plane localized force is proposed in this paper. It is based on a summary of the existing theoretical models and progressive deformation process of the web girder in the numerical simulation, which is a reproduction of a previous experiment. From the analysis of the deformation process of the web girder in the numerical simulation it is found that there are some important features which have not been considered by any of the existing models. Based on these new features, plastic analytical method is employed, and special emphasis is placed on the folding mechanism establishing and major energy dissipation pattern identifying. Thus, a new theoretical deformation model is proposed.
The proposed model is verified by two previous experiments, one is small-scale and the other is large-scale. From the force-indentation curves in comparisons, it can be found that the results of the proposed method compare well with those of the experiments. Therefore, the proposed method can be a useful part in the quick and reliable assessment of the performance of the ship structures in the accidental collision and grounding events.
Proposed Rules for Fatigue in Offshore Transport Engineering
Authors: Bos A. J. , Sohns I. 
Published: September 2014

In follow up on the study presented, during OMAE 2013 regarding the importance and influence of ocean transport on offshore structures and the necessity to design for ocean transportation of modules. The importance is emphasized that design engineers must take into account forces on structures induced by ocean transport. We also warned for the significant effects of fatigue damage on offshore structures prior to commissioning them on site.
The 2013 paper generated reactions from advisers of the IACS (International Association of Classification Societies) and lead EPC contractors to develop common rules for fatigue damage calculations and monitoring.
There are no unambiguous rules and regulations for fatigue assessment and monitoring in ocean transportation. Different rules are being applied and in many cases fatigue is not addressed at all. Causing discrepancies that are unwanted and potentially dangerous since tolerating such a situation leads to a gray area in which responsibilities are unclear and processes and equipment are not properly checked. Moreover, in this situation, no common and unambiguous rules are in place to check on vital safety procedures. A proposal for fatigue assessment that will lead to common rules for transport engineering will be discussed in order to provide offshore construction organizations with a realistic and workable set of rules and regulations for fatigue assessment and monitoring in ocean transport.
The development of the formal rules is on the agenda of the Dutch working group heavy lift and transport which is organized under the auspices of DNV.