When do young birds disperse? : Tests from studies of golden eagles in Scotland

Peer reviewedPublisher PD

A virtual environment to support the distributed design of large made-to-order products

An overview of a virtual design environment (virtual platform) developed as part of the European Commission funded VRShips-ROPAX (VRS) project is presented. The main objectives for the development of the virtual platform are described, followed by the discussion of the techniques chosen to address the objectives, and finally a description of a use-case for the platform. Whilst the focus of the VRS virtual platform was to facilitate the design of ROPAX (roll-on passengers and cargo) vessels, the components within the platform are entirely generic and may be applied to the distributed design of any type of vessel, or other complex made-to-order products

Age and sex-selective predation moderate the overall impact of predators

© 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. Acknowledgements: Thanks to J. Reid, S. Redpath, A. Beckerman and an anonymous reviewer for their helpful comments on a previous version of the manuscript. This work was partly funded by a Natural Environment Research Council studentship NE/J500148/1 to SH and a grant NE/F021402/1 to XL and by Natural Research Limited. Forest Research funded all the fieldwork on goshawks, tawny owls and field voles during 1973–1996. We thank B. Little, P. Hotchin, D. Anderson and all field assistants for their help with data collection and Forest Enterprise, T. Dearnley and N. Geddes for allowing and facilitating work in Kielder Forest. In addition, we are grateful to English Nature and the BTO for kindly issuing licences annually visit goshawk nest sites. Data accessibility: All data associated with the study which have not already been given in the text are available from the Dryad Digital Repository: http://doi.org/10.5061/dryad.h1289 (Hoy et al. 2014).Peer reviewedPublisher PD

Advancing Systems Engineering Excellence: The Marshall Systems Engineering Leadership Development Program

As NASA undertakes increasingly complex projects, the need for expert systems engineers and leaders in systems engineering is becoming more pronounced. As a result of this issue, the Agency has undertaken an initiative to develop more systems engineering leaders through its Systems Engineering Leadership Development Program; however, the NASA Office of the Chief Engineer has also called on the field Centers to develop mechanisms to strengthen their expertise in systems engineering locally. In response to this call, Marshall Space Flight Center (MSFC) has developed a comprehensive development program for aspiring systems engineers and systems engineering leaders. This presentation will summarize the two-level program, which consists of a combination of training courses and on-the-job, developmental training assignments at the Center to help develop stronger expertise in systems engineering and technical leadership. In addition, it will focus on the success the program has had in its pilot year. The program hosted a formal kickoff event for Level I on October 13, 2009. The first class includes 42 participants from across MSFC and Michoud Assembly Facility (MAF). A formal call for Level II is forthcoming. With the new Agency focus on research and development of new technologies, having a strong pool of well-trained systems engineers is becoming increasingly more critical. Programs such as the Marshall Systems Engineering Leadership Development Program, as well as those developed at other Centers, help ensure that there is an upcoming generation of trained systems engineers and systems engineering leaders to meet future design challenges

A network science-based assessment methodology for robust modular system architectures during early conceptual design

This article describes a methodology to assess, during the early conceptual design stage, the robustness, and modularity of engineering system architectures, which integrates concepts from network science with engineering systems. The application specifically focuses on the architecture of the power, propulsion, and cooling systems of a naval ship. The methodology incorporates a binary Design Structure Matrix as the basis for an assessment of redundancy and modularity effects on robustness, in response to disruption of modules in the architecture. Robustness is used to drive the module selection, which supports the formulation of a robust module configuration subject to the level of redundancy in the system architecture. The case study results demonstrated: redundancy promotes robustness of the architecture and enables modularity; however, high levels of redundancy in comparison to medium level redundancy does not significantly improve robustness. The novel contribution of this article relates to the combined quantitative assessment of redundancy, modularity and robustness in a collective methodology. This methodology supports conceptual design decision making, allowing early prediction of compliance of requirements that enable cost, development time and survivability targets to be achieved

A network tool to analyse and improve robustness of system architectures

The architecture of a system is decided at the initial stage of the design. However, the robustness of the system is not usually assessed in detail during the initial stages, and the exploration of alternative system architectures is limited due to the influence of previous designs and opinions. This article presents a novel network generator that enables the analysis of the robustness of alternative system architectures in the initial stages of design. The generator is proposed as a network tool for system architectures dictated by their configuration of source and sink components structured in a way to deliver a particular functionality. Its parameters allow exploration with theoretical patterns to define the main structure and hub structure, vary the number, size, and connectivity of hub components, define source and sink components and directionality at the hub level and adapt a redundancy threshold criterion. The methodology in this article assesses the system architecture patterns through robustness and modularity network based metrics and methods. Two naval distributed engineering system architectures are examined as the basis of reference for the simulated networks. The generator provides the capacity to create alternative complex system architecture options with identifiable patterns and key features, aiding in a broader explorative and analytical, in-depth, time and cost-efficient initial design process

Genetic markers validate using the natural phenotypic characteristics of shed feathers to identify individual northern goshawks Accipiter gentilis

Acknowledgements We are grateful to S. Piertney for allowing access to laboratory facilities and to M. Wenzel, R. Ogden and G. Murray-Dickson for their advice on genetic methods. This research was partly funded by a Natural Environment Research Council studentship NE/J500148/1 to SH and by Natural Research Limited.Peer reviewedPublisher PD

Winter distribution of willow flycatcher subspecies

The article presents a study which examines the migratory connectivity in the Willow Flycatcher subspecies throughout the winter range using mitochondrial DNA sequences as well as the morphological characteristics of 68 museum specimens obtained in the winter range in Costa Rica. It notes that the findings reveal that the overlapping and distinct regions of the winter range were occupied by the four subspecies. The specific breeding of these species is connected to the winter grounds

Mitochondrial ROS cause motor deficits induced by synaptic inactivity:implications for synapse pruning

Developmental synapse pruning refines burgeoning connectomes. The basic mechanisms of mitochondrial reactive oxygen species (ROS) production suggest they select inactive synapses for pruning: whether they do so is unknown. To begin to unravel whether mitochondrial ROS regulate pruning, we made the local consequences of neuromuscular junction (NMJ) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing Xenopus laevis tadpoles. We resolved whether: (1) synaptic inactivity increases mitochondrial ROS; and (2) antioxidants rescue synaptic inactivity induced motor deficits. Regardless of whether it was achieved with muscle (α-bugarotoxin), nerve (α-latrotoxin) targeted neurotoxins or an endogenous pruning cue (SPARC), synaptic inactivity increased mitochondrial ROS in vivo. The manganese porphyrins MnTE-2-PyP5+ and/or MnTnBuOE-2-PyP5+ blocked mitochondrial ROS to significantly reduce neurotoxin and endogenous pruning cue induced motor deficits. Selectively inducing mitochondrial ROS—using mitochondria-targeted Paraquat (MitoPQ)—recapitulated synaptic inactivity induced motor deficits; which were significantly reduced by blocking mitochondrial ROS with MnTnBuOE-2-PyP5+. We unveil mitochondrial ROS as synaptic activity sentinels that regulate the phenotypical consequences of forced synaptic inactivity at the NMJ. Our novel results are relevant to pruning because synaptic inactivity is one of its defining features