Fiaschi D.,University of Pisa |
Gianmoena L.,Marche Polytechnic University |
Parenti A.,ICES Inc
Spatial Economic Analysis | Year: 2017
Asymmetric macroeconomic volatility in European regions. Spatial Economic Analysis. This paper investigates, on the basis of a theoretical spatial model, the determinants of macroeconomic volatility of per capita gross domestic product (GDP) in a panel of 257 NUTS-2 European regions in 1992–2008, considering positive and negative fluctuations separately. Evidence is found of strong positive spatial dependence, and of considerable asymmetric effects on macroeconomic volatility of sectoral output (its composition and concentration), of composition of aggregate demand, and of other regional/country characteristics. In particular, while public expenditure exerts a stabilizing effect on both types of fluctuations, financial depth amplifies negative fluctuations. Finally, inflation fluctuations and participation in European Monetary Union (EMU) appear to have no effect on macroeconomic volatility. © 2017 Regional Studies Association
Dickey-Collas M.,ICES Inc |
Dickey-Collas M.,Institute for Marine Resources and Ecosystem Studies |
Hintzen N.T.,Institute for Marine Resources and Ecosystem Studies |
Nash R.D.M.,Norwegian Institute of Marine Research |
And 2 more authors.
ICES Journal of Marine Science | Year: 2014
The accessibility of databases of global or regional stock assessment outputs is leading to an increase in meta-analysis of the dynamics of fish stocks. In most of these analyses, each of the time-series is generally assumed to be directly comparable. However, the approach to stock assessment employed, and the associated modelling assumptions, can have an important influence on the characteristics of each time-series. We explore this idea by investigating recruitment time-series with three different recruitment parameterizations: a stock-recruitment model, a random-walk time-series model, and non-parametric "free" estimation of recruitment. We show that the recruitment time-series is sensitive to model assumptions and this can impact reference points in management, the perception of variability in recruitment and thus undermine meta-analyses. The assumption of the direct comparability of recruitment time-series in databases is therefore not consistent across or within species and stocks. Caution is therefore required as perhaps the characteristics of the time-series of stock dynamics may be determined by the model used to generate them, rather than underlying ecological phenomena. This is especially true when information about cohort abundance is noisy or lacking. © 2014 © International Council for the Exploration of the Sea 2014. All rights reserved.
Dana G.V.,Dana and Sharpe Risk Associates |
Cooper A.M.,ICES Inc |
Pennington K.M.,University of Minnesota |
Sharpe L.S.,University of Minnesota
Biological Invasions | Year: 2014
Genetic biocontrol of invasive aquatic species proposes to introduce, for control purposes, a genetically modified (GM) version of an invasive fish species to a targeted aquatic environment. Safe deployment and long term use of such technologies will depend on identifying and managing possible unintended effects to the natural environment. Environmental risk analysis (ERA) is a method for identifying the likelihood and consequences of unintended impacts, and for developing risk management strategies. For the unique situation of genetically modified biocontrol organisms (GMBOs), we review the latest thinking in ERA methodologies for GM fish and explore how terminology and assumptions from ERAs of traditional, non-modified biocontrol organisms and GM fish will need to be recast in ERAs of GMBOs. We also outline some special considerations that an ERA of a GMBOs will have to contend with: non-intuitive potential hazards; uncertainty introduced by extrapolating from domestic systems to natural ecosystems; redundancy in risk management options; and challenges of stakeholder engagement related to new technologies. © 2013 Springer Science+Business Media Dordrecht.
Heino J.,Finnish Environment Institute |
Melo A.S.,Federal University of Goais |
Siqueira T.,Claro |
Soininen J.,University of Helsinki |
And 4 more authors.
Freshwater Biology | Year: 2015
Metacommunity ecology addresses the situation where sets of local communities are connected by the dispersal of a number of potentially interacting species. Aquatic systems (e.g. lentic versus lotic versus marine) differ from each other in connectivity and environmental heterogeneity, suggesting that metacommunity organisation also differs between major aquatic systems. Here, we review findings from observational field studies on metacommunity organisation in aquatic systems. Species sorting (i.e. species are 'filtered' by environmental factors and occur only at environmentally suitable sites) prevails in aquatic systems, particularly in streams and lakes, but the degree to which dispersal limitation interacts with such environmental control varies among different systems and spatial scales. For example, mainstem rivers and marine coastal systems may be strongly affected by 'mass effects' (i.e. where high dispersal rates homogenise communities to some degree at neighbouring localities, irrespective of their abiotic and biotic environmental conditions), whereas isolated lakes and ponds may be structured by dispersal limitation (i.e. some species do not occur at otherwise-suitable localities simply because sites with potential colonists are too far away). Flow directionality in running waters also differs from water movements in other systems, and this difference may also have effects on the role of dispersal in different aquatic systems. Dispersal limitation typically increases with increasing spatial distance between sites, mass effects potentially increase in importance with decreasing distance between sites, and the dispersal ability of organisms may determine the spatial extents at which species sorting and dispersal processes are most important. A better understanding of the relative roles of species sorting, mass effects and dispersal limitation in affecting aquatic metacommunities requires the following: (i) characterising dispersal rates more directly or adopting better proxies than have been used previously; (ii) considering the nature of aquatic networks; (iii) combining correlative and experimental approaches; (iv) exploring temporal aspects of metacommunity organisation and (v) applying past approaches and statistical methods innovatively for increasing our understanding of metacommunity organisation. © 2014 John Wiley & Sons Ltd.
Lassen H.,ICES Inc |
Pedersen S.A.,ICES Inc |
Frost H.,Copenhagen University |
Hoff A.,Copenhagen University
ICES Journal of Marine Science | Year: 2013
The European Union Marine Strategy Framework Directive (MSFD) includes four descriptors of Good Environmental Status (GES) which are affected by fishing activity. These descriptors are: biodiversity, fish stocks, foodweb, and seabed integrity. This paper shows how these descriptors can be related to variables within an ecological model and how an ecological model can be used to analyse whether the fishing pressure that is estimated based on bioeconomic criteria is within general sustainable limits. The paper presents an example of such an analysis of the Eastern Baltic cod fishery using two models: a bioeconomic model and an ecological model. The models are calibrated based on historic data. The mapping between the descriptors specified by MSFD and variables available for analysis in the models is incomplete, e.g. genetics and spatial structures are not included in the models. The models can be used strategically, providing a qualitative understanding of the anticipated relative changes. © 2013 International Council for the Exploration of the Sea.
Dickey-Collas M.,ICES Inc |
Payne M.R.,Technical University of Denmark |
Trenkel V.M.,French Research Institute for Exploitation of the Sea |
ICES Journal of Marine Science | Year: 2014
The use of modelling approaches in marine science, and in particular fisheries science, is explored. We highlight that the choice of model used for an analysis should account for the question being posed or the context of the management problem. We examine a model-classification scheme based on Richard Levins' 1966 work suggesting that models can only achieve two of three desirable model attributes: realism, precision, and generality. Model creation, therefore, requires trading-off of one of these attributes in favour of the other two: however, this is often in conflict with the desires of end-users (i.e. mangers or policy developers). The combination of attributes leads to models that are considered to have empirical, mechanistic, or analytical characteristics, but not a combination of them. In fisheries science, many examples can be found of models with these characteristics. However, we suggest that models or techniques are often employed without consideration of their limitations, such as projecting into unknown space without generalism, or fitting empirical models and inferring causality. We suggest that the idea of trade-offs and limitations in modelling be considered as an essential first step in assessing the utility of a model in the context of knowledge for decision-making in management. © 2014 International Council for the Exploration of the Sea. All rights reserved.
Cadrin S.X.,University of Massachusetts Dartmouth |
Dickey-Collas M.,ICES Inc
ICES Journal of Marine Science | Year: 2014
This special volume of the ICES Journal compiles contributions from the World Conference on Stock Assessment Methods for Sustainable Fisheries (July 2013, Boston, USA). The conference was the product of a strategic initiative on stock assessment methods that engaged many national and regional fishery management organizations to assure that scientists can apply the most appropriate methods when developing management advice. An inclusive workshop was designed to evaluate the performance of a variety of model categories by applying multiple models to selected case study data as well as simulated pseudo-data that had realistic measurement error. All model applications had difficulties in recovering the simulated stock and fishing mortality trends, particularly at the end of the assessment time series, when they are most important for informing fishery management. This general result suggests that the next steps in evaluating the performance of stock assessment methods should include stock status relative to sustainable reference points, catch advice, multi-model consideration, and alternative management procedures. Recognition of the limitations of conventional stock assessment methods should promote further development of data-limited approaches, methods with time-varying parameters, or spatial complexity, and a more revolutionary shift towards the application of multispecies and ecosystem models. The contributions in this volume address methodological themes that are expected to improve the scientific basis of fishery management. Furthermore, the limitations of stock assessment methods and associated uncertainty should be more extensively considered in fishery management strategies and tactical decisions. Recommendations developed during the conference called for the establishment of a global initiative to synthesize regional advances, form guidance on best practices, promote strategic investments, and highlight research needs for fish stock assessments. © 2014 © International Council for the Exploration of the Sea 2014. All rights reserved.
Walther Y.,ICES Inc
Environmental Development | Year: 2016
ICES has successfully advanced ecosystemknowledge in a framework connecting scientists, managers, and stake holders.The instrumental developing of tools specific to regional ecosystems has proven to overcome national fragmented structures in ecosystem assessments. The framework guiding the international LME network has the explicit aim to assist developing countries in introducing EBM practice to sustain LME goods and services.Both the LME approach and the ICES approach to EBM embrace the importance of collaboration to integrate research and management views and concepts. ICES has much to offer in terms of training and capacity development for LME projects. Areas where ICES can offer scientific support and advice include traditional fish stock assessments as well as the broader IEAs.The systematic development and experience of the IEA framework in ICES could be a model that could be of substantial value to LME projects worldwide.
Dickey-Collas M.,ICES Inc
ICES Journal of Marine Science | Year: 2014
This article considers the approach taken by the ICES to integrated ecosystem assessments (IEAs) in the context of the wider evolution of IEAs and the science/policy landscape within the ICES region. It looks forward and considers the challenges facing the development of IEAs, specifically those of scoping for objectives, participatory engagement, developing indicators and targets, risk analysis, and creating tools to evaluate management measures for marine anthropogenic activities. It concludes that expectations that the implementation of IEAs will take an ordered, stepwise approach will lead to disappointment and frustration. This is a consequence of the need to operate in an adaptive manner in a complex system. The ecosystem, the science support infrastructure, and the governance systems are all complex. Plus when engaged in a debate about societal objectives, we expect to encounter a complex and changing landscape. As a community, the challenge is to find leverage mechanisms to encourage IEA efforts to provide insights and tools within resources. We will need to innovate and be responsive to the complexity of the ecosystem and governance structures encountered when performing IEA. © 2014 International Council for the Exploration of the Sea. All rights reserved.
News Article | June 2, 2008
A supercomputer at the Texas Advanced Computing Center (TACC) recently piloted a laser to perform prostate surgery on a dog. The operation was done in Houston without the intervention of a human surgeon while the Lonestar supercomputer, a Dell Linux Cluster with 5,840 processors, was in Austin. According to TACC, 'the procedure was the culmination of three years of research and development into the algorithms, computer codes, imaging technology, and cyberinfrastructure.' Please note that even if the intervention was a success, the dog ultimately died. But the researchers are confident that their approach could lead to specific treatments in five to ten years for humans. In fact, they think this is the future of surgery, bringing engineering tools into medicine. Fascinating research!!! But read more... The image above shows the "schematic of the peer to peer communication architecture used to control the laser treatment process. Feedback control is achieved through the continual interaction of the data, compute, and visualization modules." (Credit: David Fuentes, ICES) Even if the HPCwire is informative, a recent TACC news release provides more details. As explained David Fuentes, a post-doctoral student at the University of Texas at Austin's Institute for Computational Engineering and Sciences (ICES), and the central developer of the project, "We had a fifteen minute window in which a million things had to go right for this treatment to be successful. There had to be no flaw, no silly bug, everything had to go perfectly. And if that wasn't complicated enough, you add the complexity of a living animal. This is a pretty formidable problem." And J. Tinsley Oden, director of ICES and principal investigator of the project, added, "It's been an extremely challenging problem that's met one unresolved open problem after another, solved it and pushed forward. And now we have a system that's working." But how a supercomputer can be used as a surgeon? "The laser cancer treatment project uses the massive parallel processing power of supercomputers like Lonestar to perform real-time, patient-specific surgery remotely, in a way that responds to data-intensive monitoring methods. Using precise lasers, state-of-the-art thermal imaging technology, and computational methods that synthesize complex information in a fraction of a second, dynamic, data-driven laser treatments are being pursued as a minimally invasive alternative to the standard treatment of cancer. 'We're basically bringing engineering tools into medicine,' Oden said. 'We're making surgery an engineering or mathematical process.'" Please read this long news release for additional details on the process and the treatment summarized by this quote. "The treatment itself is broken into four stages: 1) Lonestar instructs the laser to heat the domain with a non-damaging calibration pulse; 2) the thermal MRI acquires baseline images of the heating and cooling of the patient’s tissue for model calibration; 3) Lonestar inputs this patient-specific information and recomputes the optimal power profile for the rest of the treatments; and 4) surgery begins, with remote visualizations and evolving predictions continuing throughout the procedure." About the communications between Austin and Houston, which were essential for the success of the operation, Fuentes said: "This is a laser treatment where the surgery is ongoing in Houston on the canine, and the laser is being controlled by Lonestar in Austin for the entire duration of the treatment. The data is orchestrated so every time a new set of thermal images is sent from Houston to Austin, the power control for the next five seconds is sent from Austin to Houston, and it's done that way for the duration of the treatment." For more information, please visit the Dynamic Data Driven Application Systems (DDDAS) website. Here are two papers of interest. The first one, "Nanoshell-Mediated Laser Surgery Simulation for Prostate Cancer Treatment" (PDF format, 19 pages, 2.33 MB) has been published in 2007 in Engineering with Computers, a Springer journal. The second document, "A Data Driven Application System for Laser Treatment of Cancer" (PDF format, 18 pages, 3.68 MB) was presented in July 2007 at the 9th National Congress on Computational Mechanics held in San Francisco, California. The above image was extracted from this document. Sources: Michael Feldman, HPCwire, May 27, 2008; and various websites You'll find related stories by following the links below.