bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal and Among‐Stream Variation in Predator Encounter Rates for Fish Prey
Authors: Harvey Bret C. , Nakamoto Rodney J. 
Published: March 2013

AbstractRecognition that predators have indirect effects on prey populations that may exceed their direct consumptive effects highlights the need for a better understanding of spatiotemporal variation in predator–prey interactions. We used photographic monitoring of tethered Rainbow Trout Oncorhynchus mykiss and Cutthroat Trout O. clarkii to quantify predator encounter rates for fish in four streams of northwestern California during winter–spring and summer. To estimate maximum encounter rates, provide the clearest contrast among streams and seasons, and provide an empirical estimate of a key parameter in an individual‐based model of stream salmonids, we consistently placed fish in shallow microhabitats that lacked cover. Over 14‐d periods, predators captured fish at 66 of the 88 locations where fish were placed. Eight species of birds (including two species of owls) and mammals were documented as capturing fish. Thirty‐six percent of the predator encounters occurred at night. Predator encounter rates varied among streams and between seasons; the best‐fitting model of survival included a stream × season interaction. Encounter rates tended to be higher in larger streams than in smaller streams and higher in winter–spring than in summer. Conversion of predator encounter rates from this study to estimates of predation risk by using published information on capture success yielded values similar to an independent estimate of predation risk obtained from calibration of an individual‐based model of the trout population in one of the study streams. The multiple mechanisms linking predation risk to population dynamics argue for additional effort to identify patterns of spatiotemporal variation in predation risk.
Trophic Niche of Invasive White Perch and Potential Interactions with Representative Reservoir Species
Authors: Feiner Zachary S. , Rice James A. , Aday D. Derek 
Published: March 2013

AbstractThe trophic dynamics of invasive species can yield insights into the mechanisms of invasion success and aid in the prediction of potential impacts on established species. Additionally, the predicted effects of an invader may differ depending on how it integrates into the resident food web and whether its resource use changes throughout the invasion process. We investigated the trophic dynamics of populations of invasive White Perch Morone americana in three large North Carolina reservoirs and evaluated the potential for impacts on members of the resident fish community. Specifically, we used stable isotope and diet analyses to evaluate their trophic niche relative to three representative species in each reservoir chosen for their widespread range, potential overlaps with White Perch, recreational value, and representation of ecological guilds based on habitat and prey sources. The species were a native littoral generalist invertivore (Bluegill Lepomis macrochirus), native littoral piscivore (Largemouth Bass Micropterus salmoides), and stocked pelagic piscivore (Striped Bass Morone saxatilis or Walleye Sander vitreus, depending on their availability). Small (<70 mm TL), medium (120–170 mm TL), and large (>200 mm TL) White Perch occupied different trophic positions, and these positions were generally consistent among reservoirs relative to the representative species. Small and medium White Perch had the largest niche areas and high diet overlap with Bluegill in two of three lakes, whereas large White Perch had moderate diet overlap with Striped Bass, Largemouth Bass, and Walleye. As a species, White Perch occupy a wide trophic niche, which may aid in successfully establishing invasive populations. However, White Perch use resources shared by other members of the fish community, which could lead to negative impacts on these species.
Rhizobial Infection Is Associated with the Development of Peripheral Vasculature in Nodules ofMedicago truncatula
Authors: Guan Dian , Stacey Nicola , Liu Chengwu , Wen Jiangqi , Mysore Kirankumar S. , Torres-Jerez Ivone , Vernié Tatiana , Tadege Million , Zhou Chuanen , Wang Zeng-yu , Udvardi Michael K. , Oldroyd Giles E.D. , Murray Jeremy D. 
Published: March 2013

AbstractNodulation in legumes involves the coordination of epidermal infection by rhizobia with cell divisions in the underlying cortex. During nodulation, rhizobia are entrapped within curled root hairs to form an infection pocket. Transcellular tubes called infection threads then develop from the pocket and become colonized by rhizobia. The infection thread grows toward the developing nodule primordia and rhizobia are taken up into the nodule cells, where they eventually fix nitrogen. The epidermal and cortical developmental programs are synchronized by a yet-to-be-identified signal that is transmitted from the outer to the inner cell layers of the root. Using a new allele of the Medicago truncatula mutant Lumpy Infections, lin-4, which forms normal infection pockets but cannot initiate infection threads, we show that infection thread initiation is required for normal nodule development. lin-4 forms nodules with centrally located vascular bundles similar to that found in lateral roots rather than the peripheral vasculature characteristic of legume nodules. The same phenomenon was observed in M. truncatula plants inoculated with the Sinorhizobium meliloti exoY mutant, and the M. truncatula vapyrin-2 mutant, all cases where infections arrest. Nodules on lin-4 have reduced expression of the nodule meristem marker MtCRE1 and do not express root-tip markers. In addition, these mutant nodules have altered patterns of gene expression for the cytokinin and auxin markers CRE1 and DR5. Our work highlights the coordinating role that bacterial infection exerts on the developing nodule and allows us to draw comparisons with primitive actinorhizal nodules and rhizobia-induced nodules on the nonlegume Parasponia andersonii.
Rotor unsteady aerodynamics model using an efficient free‐vortex method
Authors: Li Pan , Chen Renliang 
Published: March 2013

PurposeThe purpose of this paper is to present and validate an efficient time‐marching free‐vortex method for rotor wake analysis and study the rotor wake dynamics in transient and maneuvering flight conditions.Design/methodology/approachThe rotor wake is represented by vortex filament elements. The equations governing the convection, strain and viscous diffusion of the vortex elements are derived from incompressible Navier‐Stokes equations based on the viscous splitting algorithm. The initial core size of the blade tip vortices is directly computed by a vortex sheet roll‐up model. Then, a second‐order time‐marching algorithm is developed for solving the governing equations. The algorithm is formulated in explicit form to improve computing efficiency. To avoid the numerical instability, a high order variable artificial dissipative term is directly introduced into the algorithm. Finally, the developed method is applied to examine rotor wake geometries in steady‐state and maneuvering flight conditions. Comparisons between predictions and experimental results are made for rotor wake geometries, induced inflow distributions and rotor transient responses, to help validate the new method.FindingsThe algorithm is found to be numerically stable and efficient. The predicted rotor responses have good agreement with experimental data. The transient behavior of the wake dominates the rotor responses following rapid control inputs in hover. The wake curvature effect induced by rotor pitching or rolling rate significantly changes the rotor off‐axis response.Research limitations/implicationsThis method should be further validated using experimental measurements of full‐scale helicopter rotors.Originality/valueThe paper presents a new time‐marching free‐vortex wake method, which is suitable for application in helicopter flight simulation.
Attitude cooperative control of spacecraft formation via output‐feedback
Authors: Lv Yueyong , Hu Qinglei , Ma Guangfu , Zhang Jian 
Published: March 2013

PurposeThe purpose of this paper is to propose a decentralized output feedback controller for cooperative attitude regulation of spacecraft formation in absence of angular velocity feedback.Design/methodology/approachThe nonlinear relative attitude dynamic and kinematic equations represented by relative quaternion and relative angular velocity, respectively, are considered in this paper. The lead filter is employed to synthesize virtual angular velocity signal so that the design of output feedback controller is achieved. Lyapunov method is adopted to prove the stability of closed‐loop system. Considering the external disturbance, the theory of L2‐gain disturbance attenuation is employed to improve the designed controller. Numerical simulations are carried out to verify the controllers proposed.FindingsIt is found that the closed‐loop system can be guaranteed asymptotically stable in absence of external disturbance. When disturbance is considered, as long as the sufficient condition proposed is satisfied, the improved controller can render system uniformly ultimately bounded stable.Practical implicationsThe proposed output feedback control scheme can be considered as a fall‐back alternative for the case that the angular velocity sensors fail, or seen as another option for the system without angular velocity sensors at all.Originality/valueUnlike most classical works in the field of output feedback which focus on centralized scheme and neglect the disturbance, the controller proposed in this paper is able to handle the output feedback control problem of multi‐agent formation in a decentralized fashion, so as to avoid the single failure point of a centralized scheme. Meanwhile, the capability of L2‐gain disturbance attenuation is also achieved simultaneously.
Cluster flight orbit design method for fractionated spacecraft
Authors: Wang Jihe , Nakasuka Shinichi 
Published: March 2013

PurposeThe purpose of this paper is to propose an intuitive and effective cluster flight orbit design method for fractionated spacecraft.Design/methodology/approachBased on the concept of fractionated spacecraft, orbit design requirements for cluster flight in the case of fractionated spacecraft are proposed, and categorized into three requirements: stabilization requirement, passive safety requirement, and the maximum inter‐satellite distance requirement. These design requirements are then reformulated in terms of relative eccentricity and inclination vectors (E/I vectors) using a relative motion model based on relative orbital elements (ROEs). By using ROEs theory, the cluster flight orbit design issue is modelled as the distribution of relative E/I vectors for each member satellite in the cluster, and solved by combining three different heuristic search methods and one nonlinear programming (NLP) method.FindingsThe simulation results show that the NLP method is valid and efficient in solving the cluster flight orbit design problem and that for some cluster flight scenarios, the heuristic search methods can be adopted to give feasible solutions without the NLP method.Research limitations/implicationsThe cluster flight scenario in this paper is limited because the cluster should be in the near‐circular low earth orbit (LEO), and the relative distance between the member satellites should be small enough to satisfy the relative motion linearization assumption.Practical implicationsThe cluster flight orbit design method proposed in this paper can be applied by fractionated spacecraft mission designers to propose potential cluster flight orbit solutions.Originality/valueIn this paper, the relative E/I vectors method is adopted to propose an intuitive and effective cluster flight orbit design method for fractionated spacecraft.
Aerodynamic performance of Parastoo UAV
Authors: Eslami Esmaeel , Tadjfar Mehran , Najafi Saman 
Published: March 2013

PurposeThe purpose of this paper is to investigate the flow around Parastoo UAV's wing, with the aim of improving its aerodynamic performance. A major source of concern is the use of relatively large flaps in the original design. This unmanned aerial vehicle (UAV) operates at low Reynolds numbers of below 500,000 and was designed for short‐range reconnaissance.Design/methodology/approachA finite volume solver is utilized to investigate the flow over different wing designs to find a replacement for the current one. To check the accuracy of this numerical modeling, the authors first duplicate the conditions of available relevant experiments. The numerical results are in good agreement with the wind tunnel experiments. Here, the aerodynamic performances of Parastoo's wing at different flight conditions with and without the proposed modification are studied and compared.FindingsAs the original design of Parastoo uses relatively large flaps, it is found that the aerodynamic performance of Parastoo is significantly hampered due to their existence. The use of a new wing cross‐section can improve the aerodynamics efficiency of Parastoo. It is recommended that FX‐63137 airfoil is a more suitable cross section instead of Parastoo's original NACA‐63215 airfoil. It is shown that this change improves the aerodynamic performance of the UAV and with the use of smaller flaps (changing the flaperons to only ailerons), the existing payload weight can be increased by 90 per cent.Originality/valueThe issues discussed for this UAV may be of use for other small unmanned plane designers. The numerical data generated for this study are useful for other design teams, both as in direct uses of the data in their own designs and/or for the validation of their numerical methods before investigating other wing designs.
Knowledge barriers, knowledge transfer, and innovation competitive advantage in healthcare settings
Authors: Sheng Margaret L. , Chang Shen‐Yao , Teo Thompson , Lin Yuh‐Feng 
Published: March 2013

PurposeThe aim of this paper is to examine the moderating role of information communication technology (ICT) competencies in enhancing knowledge transfer and mitigating the effects of two key knowledge barriers, namely knowledge stickiness and knowledge ambiguity, thereby increasing the firm's innovation competitive advantage.Design/methodology/approachThe study is carried out in the context of the healthcare industry in Taiwan. A total of 160 questionnaires were distributed to hospitals and 112 usable responses were received, representing a response rate of 70 percent. Hierarchical regression analysis was used to analyze the data.FindingsThe results show that ICT competencies do enhance knowledge transfer inside hospitals. Although knowledge stickiness and knowledge ambiguity have negative effects on knowledge transfer, the negative effects can be moderated by ICT competencies (defined in terms of competencies in computer‐assisted instruction, interactive videoconferencing, and hand‐held technology).Practical implicationsAmong the three ICT competencies, computer‐assisted instruction and hand‐held technology have the largest and smallest effects on the relationship between knowledge barriers and knowledge transfer. The results also allow decision makers for forward‐looking allocation of ICT competencies.Originality/valueThe study presents a valid model that comprises the antecedents, moderators (three specific types of ICT competencies), and consequences of knowledge transfer for innovation competitive advantage of healthcare organizations.
A sustainable collaborative research dialogue between practitioners and academics
Authors: Chen Chun‐Yu , Jim Wu Yen‐Chun , Wu Wen‐Hsiung 
Published: March 2013

PurposeThe purpose of this paper is to investigate the co‐production of knowledge and dialogic relationships via the collaboration between business practitioners and academic researchers.Design/methodology/approachThe motivations, expectations, communication processes, and final performance of those engaged in collaborative management research are explored by applying a two‐pronged methodology with a content analysis and an e‐mail survey. The authors conducted a content analysis on 136 articles identified out of a total of 2,029 articles from six leading journals during 2006‐2011 which fulfilled the criteria of being coauthored by both professors and practitioners. An e‐mail survey of six open questions was given to pre‐screened authors in the first stage to investigate the in‐depth dialogue processes and stories of these collaborations.FindingsThe results revealed that collaboration topics of interest focused mostly on organizational behavior, business policy, and strategy, and that theoretical inquiry and case study were the most used research methods. According to the 68 valid returned e‐mail surveys, the providing of consulting services by professors in firms plays a critical role in facilitating knowledge co‐creation between practice and knowing. The findings also highlight key factors of sustainable co‐production relationships.Originality/valueThis study provides an empirical, valuable step towards an investigation into the co‐creation dialogue experiences of practitioners and academics in three dimensions: purpose, procedure, and promise.
The Bologna process in higher education: an exploratory case study in a Russian context
Authors: Esyutina Maria , Fearon Colm , Leatherbarrow Nicky 
Published: March 2013

PurposeThe aim of the current article is to discuss the role of the Bologna process in enabling quality of educational change, internationalisation and greater mobility using an example case study of a Russian university. Some discussion is provided to offer insights and inform future research and practice.Design/methodology/approachThe authors highlight some of the quality issues associated with the Bologna process and reflect on how the statements underpin quality of learning and mobility in a European higher education area (EHEA) context. They explore some of the issues raised from the documentation and examine some early experiences and challenges from a leading Russian university as part of a wider examination of higher education in a Russian context.FindingsThe Bologna Declaration was signed in 1999 by 29 European countries. The Declaration became the guiding document for the Bologna process which is now being implemented by 47 (inclusive) EU and non‐EU countries. In Russia, Bologna did not begin well and was originally resisted by employers and universities several years ago. It has recently been started again but it is still in its early stages, as Bologna is only now being implemented more fully. Nevertheless, there are issues around the two cycle system and diploma certificates. Recognition from some employers is also still an issue but less so than before. However, specialist auditing agencies can also be used in conjunction with the universities to assure quality and reassure employers going forward. There is also a strong recognition that Russian higher educational institutions have come a long way in a short space of time in terms of quality and process development.Originality/valueWhilst the research is limited to one case and is essentially qualitative and exploratory, the integrated analysis and discussion still provides useful insight and reflection concerning key issues as a consequence of recently implementing the Bologna process within the Russian educational system.
Why Agile can be a game changer for managing continuous innovation in many industries
Authors: Denning Stephen 
Published: March 2013

PurposeVeteran managers trained to respect hierarchical systems are daunted by the fundamental changes in thinking and culture that are required to implement the Agile continuous innovation approach to manufacturing. Though widely hailed by software developers it has been slow to catch on in manufacturing. This paper aims to address this issue.Design/methodology/approachTo assuage managers concerns, ten prevalent myths about Agile are addressed along with a description of how the approach really works in practice.FindingsThe paper reveals that the Agile outside‐in orientation that maximizes customer value requires a reinvention of management roles, practices, values and communications to implement it.Research limitations/implicationsIf research is reported on in the paper this section must be completed and should include suggestions for future research and any identified limitations in the research process.Practical implicationsAgile is a way of forcing either high performance or change because results are apparent so quickly, not years later when the project runs out of money and the product flops in the marketplace.Originality/valueThe article dispels many myths about Agile and shows managers how to overcome resistance to adopting the Agile approach, which addresses the central problem at the very core of a hierarchical bureaucracy, namely, its limited ability to innovate.
Using the customer journey to road test and refine the business model
Authors: Norton David W. , Pine B. Joseph 
Published: March 2013

PurposeThe article describes how to strategically analyze and stage manage the customer journey – the sequence of events that customers go through to learn about, purchase and interact with company offerings.Design/methodology/approachThe article explains how to develop a customer journey that implements a coherent strategic plan. One that follows a scripted sequence of events companies produce to deliver value to the customer, profitability to the company and differentiation from the competition.FindingsThe customer journey, when approached as a strategic design process, can provide all the elements of a business with a unifying organizational map.Research limitations/implicationsThe examples reported on in this article are drawn from the authors' consulting experience.Practical implicationsToo often companies map a customer journey without any real participation from customers themselves. It's best to start by identifying jobs customers need to get done so that companies clarify what aspects of the journey are most important to the customer.Originality/valueTop executives should make their company's goal to align its business strategy and the experiences that create most value for customers.
Fidelity Investments: adopting new models of innovation
Authors: Bukowitz Wendi R. 
Published: March 2013

PurposeThis case aims to describe what innovation looks like and how it works in Fidelity Investments, a financial services organization that is large and decentralized.Design/methodology/approachThe case looks at how the firm's internal consultants introduced idea‐management systems, idea‐management contests, design thinking, open innovation, innovation tools, coaching and mentoring and new innovation processesFindingsThe study show that internal consultants made progress by demonstrating that different ways of thinking through business problems could lead to better solutions without making a huge investment of resources – people, time, and budget.Research limitations/implicationsThe implementation results findings are based on first‐hand reporting by the author.Practical implicationsThe combination of internal consultants and business unit champions learned to create a home for innovation that focuses and leverages impact.Originality/valueThis case explains how the internal consulting unit charged with disseminating innovation processes developed the trust and cooperation of the company business units.