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  1. Modelling Organizational Preservation Goals to Guide Digital Preservation

    Directory of Open Access Journals (Sweden)

    Angela Dappert

    2009-10-01

    Full Text Available This paper is an extended and updated version of the work reported at iPres 2008. Digital preservation activities can only succeed if they go beyond the technical properties of digital objects. They must consider the strategy, policy, goals, and constraints of the institution that undertakes them and take into account the cultural and institutional framework in which data, documents and records are preserved. Furthermore, because organizations differ in many ways, a one-size-fits-all approach cannot be appropriate. Fortunately, organizations involved in digital preservation have created documents describing their policies, strategies, work-flows, plans, and goals to provide guidance. They also have skilled staff who are aware of sometimes unwritten considerations. Within Planets (Farquhar & Hockx-Yu, 2007, a four-year project co-funded by the European Union to address core digital preservation challenges, we have analyzed preservation guiding documents and interviewed staff from libraries, archives, and data centres that are actively engaged in digital preservation. This paper introduces a conceptual model for expressing the core concepts and requirements that appear in preservation guiding documents. It defines a specific vocabulary that institutions can reuse for expressing their own policies and strategies. In addition to providing a conceptual framework, the model and vocabulary support automated preservation planning tools through an XML representation.

  2. Preservation Planning in the OAIS Model

    Institute of Scientific and Technical Information of China (English)

    STEPHAN STRODL; ANDREAS RAUBER

    2008-01-01

    The OAIS model has gained widespread acceptance as the fundamental design reference model for an archival system by the digital library community.One of its core entities is Preservation Planning,for which central functional entities are given yet without every detail breaking down into activities requirements.The Planets Preservation Planning approach addresses this by providing a way to make informed and accountable decisions on which preservation strategy to implement in order to most suitably preserve digital objects for a given preservation context.It allows the explicit definition of requirements and goals and offers a systematic way to evaluate preservation strategies.This paper shows the implementation of the Develop Preservation Strategies and Standards function of the OAIS model through the Planets Preservation Planning approach.Moreover,the paper examines the information flows within the OAIS Preservation Planning entity and with other functional entities with respect to the Planets model.

  3. Evaluation of Natural Food Preservatives in Domestic and Imported Cheese

    Science.gov (United States)

    Paik, Hyun-Dong

    2016-01-01

    In milk and milk products, a number of organic acids naturally occur. We investigated the contents of some naturally occurred food preservatives (sorbic acid, benzoic acid, propionic acid, nitrite, and nitrate) contained in domestic and imported cheeses to establish the standard for the allowable range of food preservatives content in cheese. 8 kinds of domestic precheeses (n=104), 16 kinds of domestic cured cheeses (n=204) and 40 kinds of imported cheeses (n=74) were collected. Each domestic cheese was aged for a suitable number of months and stored for 2 mon at 5℃ and 10℃. No preservatives were detected in domestic soft and fresh cheeses, except cream cheese. In case of semi-hard cheeses, 2-5 mg/kg of benzoic acid was detected after 1-2 mon of aging. In imported cheeses, only benzoic acid and propionic acid were detected. The average benzoic acid and propionic acid contents in semi-hard cheese were 8.73 mg/kg and 18.78 mg/kg, respectively. Specifically, 1.16 mg/kg and 6.80 mg/kg of benzoic acid and propionic acid, respectively, were contained in soft cheese, 3.27 mg/kg and 2.84 mg/kg, respectively, in fresh cheese, 1.87 mg/kg and not detected, respectively, in hard cheese, and 2.07 mg/kg and 182.26 mg/kg, respectively, in blended processed cheese. PMID:27621695

  4. Evaluation of Natural Food Preservatives in Domestic and Imported Cheese.

    Science.gov (United States)

    Park, Sun-Young; Han, Noori; Kim, Sun-Young; Yoo, Mi-Young; Paik, Hyun-Dong; Lim, Sang-Dong

    2016-01-01

    In milk and milk products, a number of organic acids naturally occur. We investigated the contents of some naturally occurred food preservatives (sorbic acid, benzoic acid, propionic acid, nitrite, and nitrate) contained in domestic and imported cheeses to establish the standard for the allowable range of food preservatives content in cheese. 8 kinds of domestic precheeses (n=104), 16 kinds of domestic cured cheeses (n=204) and 40 kinds of imported cheeses (n=74) were collected. Each domestic cheese was aged for a suitable number of months and stored for 2 mon at 5℃ and 10℃. No preservatives were detected in domestic soft and fresh cheeses, except cream cheese. In case of semi-hard cheeses, 2-5 mg/kg of benzoic acid was detected after 1-2 mon of aging. In imported cheeses, only benzoic acid and propionic acid were detected. The average benzoic acid and propionic acid contents in semi-hard cheese were 8.73 mg/kg and 18.78 mg/kg, respectively. Specifically, 1.16 mg/kg and 6.80 mg/kg of benzoic acid and propionic acid, respectively, were contained in soft cheese, 3.27 mg/kg and 2.84 mg/kg, respectively, in fresh cheese, 1.87 mg/kg and not detected, respectively, in hard cheese, and 2.07 mg/kg and 182.26 mg/kg, respectively, in blended processed cheese.

  5. Modelling the Costs of Preserving Digital Assets

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

    2012-01-01

    on experiences from a Danish project to develop a cost model. It was found that a generic cost model should account for the nature of the organisation and the assets to be preserved, and for all major preservation activities and cost drivers. In addition, it should describe accounting principles. It was proposed......Information is increasingly being produced in digital form, and some of it must be preserved for the longterm. Digital preservation includes a series of actively managed activities that require on-going funding. To obtain sufficient resources, there is a need for assessing the costs...... and the benefits accrued by preserving the assets. Cost data is also needed for optimizing activities and comparing the costs of different preservation alternatives. The purpose of this study is to analyse generic requirements for modelling the cost of preserving digital assets. The analysis was based...

  6. Modelling the Costs of Preserving Digital Assets

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

    2012-01-01

    and the benefits accrued by preserving the assets. Cost data is also needed for optimizing activities and comparing the costs of different preservation alternatives. The purpose of this study is to analyse generic requirements for modelling the cost of preserving digital assets. The analysis was based......Information is increasingly being produced in digital form, and some of it must be preserved for the longterm. Digital preservation includes a series of actively managed activities that require on-going funding. To obtain sufficient resources, there is a need for assessing the costs...... on experiences from a Danish project to develop a cost model. It was found that a generic cost model should account for the nature of the organisation and the assets to be preserved, and for all major preservation activities and cost drivers. In addition, it should describe accounting principles. It was proposed...

  7. Environmental sustainability model and biodiversity preservation in Central Rhodopes

    Directory of Open Access Journals (Sweden)

    Zlatka Grigorova

    2013-03-01

    In fact that model is composed of many components and considers a number of important aspects. Its application will contribute to the sustainable use of natural resources and preserved biodiversity for future generations.

  8. Preservatives as important etiologic factors of allergic contact dermatitis

    Directory of Open Access Journals (Sweden)

    Beata Kręcisz

    2015-07-01

    Full Text Available Background: Preservatives present in cosmetics and other industrial products can cause allergic contact dermatitis. The aim of the study was to assess the frequency of allergy to selected preservatives in consecutive patients examined due to contact dermatitis in the Nofer Institute of Occupational Medicine, Łódź, and to establish whether individuals sensitized to formaldehyde react simultaneously to formaldehyde releasers. Material and Methods: A group of 405 patients (308 females and 97 males was examined in 2011–2013. In all participants patch tests with a series of 13 preservatives (paraben mix, formaldehyde, Quaternium 15, chloromethylisothiazolinone/methylisothiazolinone mix, methyldibromoglutaronitrile, diazolidinyl urea, imidazolidinyl urea, DMDM hydantoin, 2-bromo-2-nitropropane-1,3-diol, iodopropynyl butylcarbamate, benzalkonium chloride, sodium metabisulfite, produced by Chemotechnique Diagnostics, Sweden were performed. Results: Of the 405 patients 74 (including 52 females showed positive results of patch tests. Contact allergy to at least 1 preservative was noted in 47 (11.6% patients, including 34 (11% females and 13 (13.4% males. Methylisothiazolinone proved to be the most frequent sensitizer – 4.7% (5.2% females, 3.1% males while parabens, 2-bromo-2-nitropropane-1,3-diol and imidazolidinyl urea (0.2% were found to be the least frequent. Fourteen (3.4% participants, 10 women and 4 men, were allergic to formaldehyde and/or formaldehyde releasers. In 11 (78.6% of them monovalent hypersensitivity was observed. In 13 (3.2% of the examined group patients allergy to preservatives might have been of occupational origin. Conclusions: Preservatives, particularly isothiazolinones, are significant causal factors of allergic contact dermatitis, including occupational cases. Individuals sensitized to formaldehyde may react simultaneously to formaldehyde releasers, however, such reactions are relatively rare. Med Pr 2015;66(3:327–332

  9. Analysis of Price and Product Competition from Imports in the Preserved Mushrooms Market in Australia

    OpenAIRE

    Rodgers, Trudi; Fleming, Euan M.; Villano, Renato A.

    2006-01-01

    The Australian preserved mushrooms industry is one of a number of industries in the horticultural sector that is under threat from cheaper imported products. The Australian Customs Service is currently investigating the alleged dumping of Chinese imported cans of preserved mushrooms that feature prominently on supermarket shelves. Evidence exists that cheaper imported Chinese products have incurred injury in the Australian market. These Chinese imports have penetrated the Australian preserved...

  10. Reduction of Protein Networks Models by Passivity Preserving Projection

    Institute of Scientific and Technical Information of China (English)

    Luca Mesin; Flavio Canavero; Lamberto Rondoni

    2013-01-01

    Reduction of complex protein networks models is of great importance.The accuracy of a passivity preserving algorithm (PRIMA) for model order reduction (MOR) is here tested on protein networks,introducing innovative variations of the standard PRIMA method to fit the problem at hand.The reduction method does not require to solve the complete system,resulting in a promising tool for studying very large-scale models for which the full solution cannot be computed.The mathematical structure of the considered kinetic equations is preserved.Keeping constant the reduction factor,the approximation error is lower for larger systems.

  11. Modelling OAIS Compliance for Disaggregated Preservation Services

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    Gareth Knight

    2007-07-01

    Full Text Available The reference model for the Open Archival Information System (OAIS is well established in the research community as a method of modelling the functions of a digital repository and as a basis in which to frame digital curation and preservation issues. In reference to the 5th anniversary review of the OAIS, it is timely to consider how it may be interpreted by an institutional repository. The paper examines methods of sharing essential functions and requirements of an OAIS between two or more institutions, outlining the practical considerations of outsourcing. It also details the approach taken by the SHERPA DP Project to introduce a disaggregated service model for institutional repositories that wish to implement preservation services.

  12. A diffuse interface model with immiscibility preservation

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Arpit, E-mail: atiwari2@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Freund, Jonathan B., E-mail: jbfreund@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Pantano, Carlos [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2013-11-01

    A new, simple, and computationally efficient interface capturing scheme based on a diffuse interface approach is presented for simulation of compressible multiphase flows. Multi-fluid interfaces are represented using field variables (interface functions) with associated transport equations that are augmented, with respect to an established formulation, to enforce a selected interface thickness. The resulting interface region can be set just thick enough to be resolved by the underlying mesh and numerical method, yet thin enough to provide an efficient model for dynamics of well-resolved scales. A key advance in the present method is that the interface regularization is asymptotically compatible with the thermodynamic mixture laws of the mixture model upon which it is constructed. It incorporates first-order pressure and velocity non-equilibrium effects while preserving interface conditions for equilibrium flows, even within the thin diffused mixture region. We first quantify the improved convergence of this formulation in some widely used one-dimensional configurations, then show that it enables fundamentally better simulations of bubble dynamics. Demonstrations include both a spherical-bubble collapse, which is shown to maintain excellent symmetry despite the Cartesian mesh, and a jetting bubble collapse adjacent a wall. Comparisons show that without the new formulation the jet is suppressed by numerical diffusion leading to qualitatively incorrect results.

  13. Cost Model for Digital Preservation: Cost of Digital Migration

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

    2011-01-01

    The Danish Ministry of Culture has funded a project to set up a model for costing preservation of digital materials held by national cultural heritage institutions. The overall objective of the project was to increase cost effectiveness of digital preservation activities and to provide a basis...... for comparing and estimating future cost requirements for digital preservation. In this study we describe an activity-based costing methodology for digital preservation based on the Open Archice Information System (OAIS) Reference Model. Within this framework, which we denote the Cost Model for Digital...... Preservation (CMDP), the focus is on costing the functional entity Preservation Planning from the OAIS and digital migration activities. In order to estimate these costs we have identified cost-critical activities by analysing the functions in the OAIS model and the flows between them. The analysis has been...

  14. Modelling the Cost and Quality of Preservation Imaging and Archiving

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad

    2009-01-01

    in the OAIS Reference Model. The cost model divides the OAIS functions in a hierarchy of cost critical activities and measurable components, which are implemented as formulas in a spreadsheet. So far the model has only been completed for activities relating to preservation planning and digital migrations......, fire and other risks. In this PhD thesis it is examined how one may evaluate the long‐term costs and benefits to cultural heritage institutions of different preservation strategies for digital copies. The investigated alternatives are preserving the copies in a digital repository, and printing...... the files out on microfilm and preserving them in a non‐digital repository. In order to obtain empirical data and to understand the decisive cost factors in preservation copying, a case study was set up in which degrading sheet‐film negatives were digitised. Requirements for image quality and metadata were...

  15. Modelling the Cost and Quality of Preservation Imaging and Archiving

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad

    2009-01-01

    materials held by national cultural heritage institutions in Denmark, a study was undertaken to provide a generic cost model for digital preservation. The outcome of the study is an activity based cost model, which accounts for full economic costs. It is structured around the functional descriptions...... investigated and specifications based on best practice and testing established. Also, the image quality parameters, which influence the long term preservation costs, were identified. In addition, the suitability for preservation of different image file formats and compression algorithms was evaluated...... in the OAIS Reference Model. The cost model divides the OAIS functions in a hierarchy of cost critical activities and measurable components, which are implemented as formulas in a spreadsheet. So far the model has only been completed for activities relating to preservation planning and digital migrations...

  16. Semantics-preserving bag-of-words models and applications.

    Science.gov (United States)

    Wu, Lei; Hoi, Steven C H; Yu, Nenghai

    2010-07-01

    The Bag-of-Words (BoW) model is a promising image representation technique for image categorization and annotation tasks. One critical limitation of existing BoW models is that much semantic information is lost during the codebook generation process, an important step of BoW. This is because the codebook generated by BoW is often obtained via building the codebook simply by clustering visual features in Euclidian space. However, visual features related to the same semantics may not distribute in clusters in the Euclidian space, which is primarily due to the semantic gap between low-level features and high-level semantics. In this paper, we propose a novel scheme to learn optimized BoW models, which aims to map semantically related features to the same visual words. In particular, we consider the distance between semantically identical features as a measurement of the semantic gap, and attempt to learn an optimized codebook by minimizing this gap, aiming to achieve the minimal loss of the semantics. We refer to such kind of novel codebook as semantics-preserving codebook (SPC) and the corresponding model as the Semantics-Preserving Bag-of-Words (SPBoW) model. Extensive experiments on image annotation and object detection tasks with public testbeds from MIT's Labelme and PASCAL VOC challenge databases show that the proposed SPC learning scheme is effective for optimizing the codebook generation process, and the SPBoW model is able to greatly enhance the performance of the existing BoW model.

  17. nestor Guideline for Preservation Planning – a Process Model

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    Sabine Schrimpf

    2014-02-01

    Full Text Available The nestor guideline for preservation planning is the latest in a series of nestor publications. nestor is the German competence network for digital preservation and it offers all interested parties from the private and public domains the possibility to participate in working groups. The guideline for preservation planning is the result of such a working group, which discussed the conceptual and practical issues of implementing the OAIS Functional Entity “Preservation Planning”.The guideline describes a process model and offers some guidance on potential implementations. It integrates and builds on recognized community concepts like Significant Properties, the OAIS Designated Community, the National Archives of Australia’s Performance Model, the PREMIS concept of Intellectual Entities and Representations, and the PLANET’s approach to preservation planning. Furthermore, it introduces the concepts “intended use” (Nutzungsziele, “information type” (Informationstyp and “preservation group” (Erhaltungsgruppe. The purpose of these new categories is that information objects shall be grouped by information type (e.g., audio, video, text… and intended use (e.g., reading for pleasure, search for specific information… to preservation groups for automatic processing. Significant properties can then be derived for whole preservation groups. The file format alone is considered as not completely sufficient for such categorisation. Some exemplary implementation solutions of the new concepts are presented in an annex.The guideline takes into account that resources for preservation planning and preservation actions are limited and has therefore adopted 4 premises: adequacy, financial viability, automation, and authenticity of archived objects. Its pragmatic approach becomes apparent in the definition and explanation of these dimensions. The guideline is written from the point of view of representatives of memory institutions, i

  18. Cost Model for Digital Preservation: Cost of Digital Migration

    Directory of Open Access Journals (Sweden)

    Ulla Bøgvad Kejser

    2011-03-01

    Full Text Available The Danish Ministry of Culture has funded a project to set up a model for costing preservation of digital materials held by national cultural heritage institutions. The overall objective of the project was to increase cost effectiveness of digital preservation activities and to provide a basis for comparing and estimating future cost requirements for digital preservation. In this study we describe an activity-based costing methodology for digital preservation based on the Open Archice Information System (OAIS Reference Model. Within this framework, which we denote the Cost Model for Digital Preservation (CMDP, the focus is on costing the functional entity Preservation Planning from the OAIS and digital migration activities. In order to estimate these costs we have identified cost-critical activities by analysing the functions in the OAIS model and the flows between them. The analysis has been supplemented with findings from the literature, and our own knowledge and experience. The identified cost-critical activities have subsequently been deconstructed into measurable components, cost dependencies have been examined, and the resulting equations expressed in a spreadsheet. Currently the model can calculate the cost of different migration scenarios for a series of preservation formats for text, images, sound, video, geodata, and spreadsheets. In order to verify the model it has been tested on cost data from two different migration projects at the Danish National Archives (DNA. The study found that the OAIS model provides a sound overall framework for the cost breakdown, but that some functions need additional detailing in order to cost activities accurately. Running the two sets of empirical data showed among other things that the model underestimates the cost of manpower-intensive migration projects, while it reinstates an often underestimated cost, which is the cost of developing migration software. The model has proven useful for estimating the

  19. Towards The Long-Term Preservation of Building Information Models

    DEFF Research Database (Denmark)

    Beetz, Jacob; Dietze, Stefan; Berndt, René

    2013-01-01

    primarily been on textual and audio-visual media types. With the recent paradigm shift in architecture and construction from analog 2D plans and scale models to digital 3D information models of buildings, long-term preservation efforts must turn their attention to this new type of data. Currently......Long-term preservation of information about artifacts of the built environment is crucial to provide the ability to retrofit legacy buildings, to preserve cultural heritage, to ensure security precautions, to enable knowledge-reuse of design and engineering solutions and to guarantee the legal...... liabilities of all stakeholders (e.g. designer, engineers). Efforts for the digital preservation of information have come a long way and a number of mature methods, frameworks, guidelines and software systems are at the disposal of librarians and archivists. However, the focus of these developments has...

  20. The Importance of Digital Methods in Preservation of Cultural Heritage the Example of Zirnikli Mansion

    Science.gov (United States)

    Kan, T.; Buyuksalih, G.; Kaya, Y.; Baskaraca, A. P.

    2017-05-01

    Documentation in maintaining cultural properties is a highly important stage of work for determination of the unique properties. The researches having been carried out over years to increase the accuracy of documentation enabled it to reach such a point that the properties can be scanned by 3D laser scanners today. In order for the lost parts of the civil architecture examples required to be preserved in the context of cultural texture to be found and reconstructed, precise measurement have gained importance in documentation of the current status. Over years, major losses have arisen in the cultural texture situated around Erzurum Castle where the unique architectural examples are placed together. In this study, the importance of the 3D documentation in preserving the cultural properties is discussed in the context of Zırnıklı Vehbi Bey Mansion situated near to the Castle. The CAD drawings of this structure which has significantly lost its spatial integrity has been generated from the 3D laser point clouds, then the restitution and the restoration projects of the monument have been prepared accordingly.

  1. Cost Model for Digital Preservation: Cost of Digital Migration

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

    2011-01-01

    calculate the cost of different migration scenarios for a series of preservation formats for text, images, sound, video, geodata, and spreadsheets. In order to verify the model it has been tested on cost data from two different migration projects at the Danish National Archives (DNA). The study found...... Preservation (CMDP), the focus is on costing the functional entity Preservation Planning from the OAIS and digital migration activities. In order to estimate these costs we have identified cost-critical activities by analysing the functions in the OAIS model and the flows between them. The analysis has been...... that the OAIS model provides a sound overall framework for the cost breakdown, but that some functions need additional detailing in order to cost activities accurately. Running the two sets of empirical data showed among other things that the model underestimates the cost of manpower-intensive migration...

  2. USEPA SHEDS MODEL: METHODOLOGY FOR EXPOSURE ASSESSMENT FOR WOOD PRESERVATIVES

    Science.gov (United States)

    A physically-based, Monte Carlo probabilistic model (SHEDS-Wood: Stochastic Human Exposure and Dose Simulation model for wood preservatives) has been applied to assess the exposure and dose of children to arsenic (As) and chromium (Cr) from contact with chromated copper arsenat...

  3. Towards Preserving Model Coverage and Structural Code Coverage

    Directory of Open Access Journals (Sweden)

    Raimund Kirner

    2009-01-01

    Full Text Available Embedded systems are often used in safety-critical environments. Thus, thorough testing of them is mandatory. To achieve a required structural code-coverage criteria it is beneficial to derive the test data at a higher program-representation level than machine code. Higher program-representation levels include, beside the source-code level, languages of domain-specific modeling environments with automatic code generation. For a testing framework with automatic generation of test data this will enable high retargetability of the framework. In this article we address the challenge of ensuring that the structural code coverage achieved at a higher program representation level is preserved during the code generations and code transformations down to machine code. We define the formal properties that have to be fullfilled by a code transformation to guarantee preservation of structural code coverage. Based on these properties we discuss how to preserve code coverage achieved at source-code level. Additionally, we discuss how structural code coverage at model level could be preserved. The results presented in this article are aimed toward the integration of support for preserving structural code coverage into compilers and code generators.

  4. Privacy Preservation in Role-based Access Control Model

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    Zuo Chen

    2011-08-01

    Full Text Available Privacy preservation is a crucial problem in resource sharing and collaborating among multi-domains. Based on this problem, we propose a role-based access control model for privacy preservation. This scheme avoided the privacy leakage of resources while implementing access control, and it has the advantage of lower communication overhead. We demonstrate this scheme meets the IND-CCA2 semantic security by using random oracle. The simulation result shows this scheme has better execution efficiency and application effects.

  5. Supply chain production model with preservation technology under fuzzy environment

    Directory of Open Access Journals (Sweden)

    S.R. Singh

    2014-06-01

    Full Text Available In this paper, an attempt is made to characterize the preservation technology for deteriorating items to reduce the deterioration rate. This model assumes a single producer and single supplier and formulates a production model with a time varying rate of deterioration rate. Here production and demand are treated as a fuzzy variables and total cost is minimized for both the crisp and fuzzy model. Shortage is allowed on the supplier’s part, which is partially backlogged. A solution procedure is presented to determine an optimal replenishment cycle and total cost per unit time, which is a convex function of preservation technology cost. Results have been validated with relevant example. In a way, the proposed model provides a unique theory to reduce the deterioration rate for the production model.

  6. The Importance of On-Going Maintenance in Preserving the Heritage Listed Buildings

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    M.A.A. Rahman

    2012-01-01

    Full Text Available Maintenance is not only important in ensuring the condition and physical of the old building to operate safely and effectively, but it also for an activity that is important in determining the life long of the building, so that it can be preserve and be inherit by the next generation. The need of maintenance is not only on repairing but more towards prevention method. According to the previous study, maintenance is done reactively; this further will cost serious problems in future. Therefore maintenance need good planning from the early stage and is followed with on-going implementation from time to time by all those who are responsible in it. In conjunction with this, this paper is to discuss about the importance of on-going maintenance in order to manage the old building after it has been gazette as heritage listed. At the end of the discussion, several strategies have been put forward in order to stimulate the practice of on-going maintenance as an initiative to encourage the culture of maintenance and also help to increase the quality process in a more effective maintenance management.

  7. Long-term preservation of early formed mantle heterogeneity by mobile lid convection: Importance of grainsize evolution

    Science.gov (United States)

    Foley, Bradford J.; Rizo, Hanika

    2017-10-01

    The style of tectonics on the Hadean and Archean Earth, particularly whether plate tectonics was in operation or not, is debated. One important, albeit indirect, constraint on early Earth tectonics comes from observations of early-formed geochemical heterogeneities: 142Nd and 182W anomalies recorded in Hadean to Phanerozoic rocks from different localities indicate that chemically heterogeneous reservoirs, formed during the first ∼500 Myrs of Earth's history, survived their remixing into the mantle for over 1 Gyrs. Such a long mixing time is difficult to explain because hotter mantle temperatures, expected for the early Earth, act to lower mantle viscosity and increase convective vigor. Previous studies found that mobile lid convection typically erases heterogeneity within ∼100 Myrs under such conditions, leading to the hypothesis that stagnant lid convection on the early Earth was responsible for the observed long mixing times. However, using two-dimensional Cartesian convection models that include grainsize evolution, we find that mobile lid convection can preserve heterogeneity at high mantle temperature conditions for much longer than previously thought, because higher mantle temperatures lead to larger grainsizes in the lithosphere. These larger grainsizes result in stronger plate boundaries that act to slow down surface and interior convective motions, in competition with the direct effect temperature has on mantle viscosity. Our models indicate that mobile lid convection can preserve heterogeneity for ≈0.4-1 Gyrs at early Earth mantle temperatures when the initial heterogeneity has the same viscosity as the background mantle, and ≈1-4 Gyrs when the heterogeneity is ten times more viscous than the background mantle. Thus, stagnant lid convection is not required to explain long-term survival of early formed geochemical heterogeneities, though these heterogeneities having an elevated viscosity compared to the surrounding mantle may be essential for their

  8. Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain

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    Karen E. Samonds

    2006-12-01

    Full Text Available The origin of Madagascar’s highly endemic vertebrate fauna remains one of the great unsolved mysteries of natural history. From what landmasses did the basal stocks of this unique and imbalanced fauna come? When and how did the ancestral populations arrive on the island? How rapidly did they diversify, and why? The most direct means of addressing these questions, and other enigmas concerning the evolutionary and biogeographic history of Madagascar’s vertebrate fauna, is through discovery of fossils from a sequence of well-dated geological horizons. Many fossils relevant to these queries have been discovered by paleontologists in recent years ... but many more are being lost to commercial enterprises, both foreign and domestic, that have little or no regard for the scientific significance of fossils. The objectives of this essay are to 1 provide an overview of Madagascar’s vertebrate fossil record and its importance, 2 raise awareness concerning the illegal collection, exportation, and sale of vertebrate fossils, and 3 stress the importance of keeping vertebrate fossils from the island in the public domain. In light of these issues, we underscore the necessity for development of adequate repositories and support infrastructure in Madagascar to safeguard and display the country’s vertebrate fossil collections; doing so would ensure the preservation and appreciation of Madagascar’s rich natural heritage for future generations of scientists and Malagasy citizens alike.

  9. Research on Modelling Digital Paper-cut Preservation

    Institute of Scientific and Technical Information of China (English)

    Xiao-Fen Wang; Ying-Rui Liu; Wen-Sheng Zhang

    2009-01-01

    This paper studies the model of the digital preservation of paper-cut after analyzing the state-of-the-art of the preservation of intangible cultural heritage at home and abroad, focusing on paper-cutting in Hebei, China in a comprehensive approach of sociology, anthropology, folk art, folklore, communication, computer, and information science. Models, methods, and solutions for the preservation and retention of national and folk cultural heritage are proposed. A virtual multimedia interactive system framework of the digital preservation of national and folk cultural heritage is constructed. The standards of paper-cut digitization arc studied. The main content of the paper involves: regulated data collection and recording of the scattered Chinese folk paper-cut works in Hebei; digitization, optimization, compression, classification, icon and pattern extraction, vectorization, and work analysis of the first-hand material. This paper also investigates the demonstration, dissemination, database construction, and retrieval of the classified material, icons, and patterns; the demonstration of the reconstruction and application of icon and pattern database; the design and development of an immersive virtual gaming platform of the multi-media scenes and production process of folk paper-cut.

  10. Importance of oestrogen receptors to preserve functional β-cell mass in diabetes.

    Science.gov (United States)

    Tiano, Joseph P; Mauvais-Jarvis, Franck

    2012-02-14

    Protecting the functional mass of insulin-producing β cells of the pancreas is a major therapeutic challenge in patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM). The gonadal hormone 17β-oestradiol (E2) is involved in reproductive, bone, cardiovascular and neuronal physiology. In rodent models of T1DM and T2DM, treatment with E2 protects pancreatic β cells against oxidative stress, amyloid polypeptide toxicity, lipotoxicity and apoptosis. Three oestrogen receptors (ERs)--ERα, ERβ and the G protein-coupled ER (GPER)--have been identified in rodent and human β cells. Whereas activation of ERα enhances glucose-stimulated insulin biosynthesis, reduces islet toxic lipid accumulation and promotes β-cell survival from proapoptotic stimuli, activation of ERβ increases glucose-stimulated insulin secretion. However, activation of GPER protects β cells from apoptosis, raises glucose-stimulated insulin secretion and lipid homeostasis without affecting insulin biosynthesis. Oestrogens are also improving islet engraftment in rodent models of pancreatic islet transplantation. This Review describes developments in the role of ERs in islet insulin biosynthesis and secretion, lipid homeostasis and survival. Moreover, we discuss why and how enhancing ER action in β cells without the undesirable effect of general oestrogen therapy is a therapeutic avenue to preserve functional β-cell mass in patients with diabetes mellitus.

  11. Digital preservation of cultural and scientific heritage: involving university students to raise awareness of its importance

    Directory of Open Access Journals (Sweden)

    Paula Redweik

    2017-05-01

    Full Text Available Cultural heritage is a relevant issue in contemporary society. While its preservation is a challenge, its dissemination, can contribute for an economic balance between costs and benefits.  Scientific  heritage  can  be  considered  as  a  special domain  of  cultural  heritage, not yet sought  by  the  mass  tourism, but worth being preserved as the roots of today’s knowledge.  Considering  that  university  students  of  engineering  and computer  science traditionally  do  not  address cultural or scientific heritage issues in their syllabus, and that they constitute a layer of young citizens that will come to be influential  in  the  future  of  society,  an  effort  was  undertaken  to  focus  on  this  theme  in  disciplines  of  different  courses, allying  the  learning  of  technical  skills  with  the  natural  interest  of  younger  people  for  3D  and  animation  for  the  profit  of heritage. The goal was to raise the awareness of this particular group to the importance of maintaining heritage issues, in particular,  in  a  virtual  way,  both  for  documentation  and  for  divulgating  their  existence.  Raising  funds  for  buildings’ restoration, attracting the public to visit buildings and collections that are outside the usual tourism routes, contributing to revenue  generation,  or  allowing  virtual  visits  of  not  accessible  issues,  complementing  physical  visits  on  site,  were  the general  aims of  the  proposed  projects.  A survey was undertaken under the participating students to evaluate how the projects influenced their attitude towards heritage. The obtained feedback was very positive: 76% agreed that the project alerted them for the importance of preserving historical and cultural heritage, while 72% considered it was interesting that the topic of digital cultural heritage was used for the assessments of

  12. A Family Therapy Model For Preserving Independence in Older Persons: Utilization of the Family of Procreation.

    Science.gov (United States)

    Quinn, William H.; Keller, James F.

    1981-01-01

    Presents a family therapy model that utilizes the Bowen theory systems framework. The framework is adapted to the family of procreation, which takes on increased importance in the lives of the elderly. Family therapy with the aged can create more satisfying intergenerational relationships and preserve independence. (Author)

  13. Asymptotic-Preserving methods and multiscale models for plasma physics

    CERN Document Server

    Degond, Pierre

    2016-01-01

    The purpose of the present paper is to provide an overview of Asymptotic-Preserving methods for multiscale plasma simulations by addressing three singular perturbation problems. First, the quasi-neutral limit of fluid and kinetic models is investigated in the framework of non magnetized as well as magnetized plasmas. Second, the drift limit for fluid descriptions of thermal plasmas under large magnetic fields is addressed. Finally efficient numerical resolutions of anisotropic elliptic or diffusion equations arising in magnetized plasma simulation are reviewed.

  14. A mixed model reduction method for preserving selected physical information

    Science.gov (United States)

    Zhang, Jing; Zheng, Gangtie

    2017-03-01

    A new model reduction method in the frequency domain is presented. By mixedly using the model reduction techniques from both the time domain and the frequency domain, the dynamic model is condensed to selected physical coordinates, and the contribution of slave degrees of freedom is taken as a modification to the model in the form of effective modal mass of virtually constrained modes. The reduced model can preserve the physical information related to the selected physical coordinates such as physical parameters and physical space positions of corresponding structure components. For the cases of non-classical damping, the method is extended to the model reduction in the state space but still only contains the selected physical coordinates. Numerical results are presented to validate the method and show the effectiveness of the model reduction.

  15. Counterexample-Preserving Reduction for Symbolic Model Checking

    Directory of Open Access Journals (Sweden)

    Wanwei Liu

    2014-01-01

    Full Text Available The cost of LTL model checking is highly sensitive to the length of the formula under verification. We observe that, under some specific conditions, the input LTL formula can be reduced to an easier-to-handle one before model checking. In such reduction, these two formulae need not to be logically equivalent, but they share the same counterexample set w.r.t the model. In the case that the model is symbolically represented, the condition enabling such reduction can be detected with a lightweight effort (e.g., with SAT-solving. In this paper, we tentatively name such technique “counterexample-preserving reduction” (CePRe, for short, and the proposed technique is evaluated by conducting comparative experiments of BDD-based model checking, bounded model checking, and property directed reachability-(IC3 based model checking.

  16. Importance of compensatory heart rate increase during myocardial ischemia to preserve appropriate oxygen kinetics.

    Science.gov (United States)

    Yoshida, Sadamitsu; Adachi, Hitoshi; Murata, Makoto; Tomono, Junichi; Oshima, Shigeru; Kurabayashi, Masahiko

    2017-09-01

    Myocardial ischemia induces cardiac dysfunction, resulting in insufficient oxygen supply to peripheral tissues and mismatched energy production during exercise. To relieve the insufficient oxygen supply, heart rate (HR) response is augmented; however, beta-adrenergic receptor blockers (BB) restrict HR response. Although BB are essential drugs for angina pectoris, the effect of BB on exercise tolerance in patients with angina has not been studied. The aim of this study was to clarify the importance of HR augmentation to preserve exercise tolerance in patients with angina pectoris. Forty-two subjects who underwent cardiopulmonary exercise testing (CPX) to detect myocardial ischemia were enrolled. CPX was performed until exhaustion or onset of significant myocardial ischemia using a ramp protocol. Subjects were assigned to three groups (Group A: with ST depression during CPX with significant coronary stenosis and taking BB; Group B: with ST depression and not taking BB; Group C: without ST depression and not taking BB). HR response to exercise was evaluated during the following two periods: below and above ischemic threshold (IT). In Group C, it was evaluated during the first 2min and the last 2min of a ramp exercise. No significant differences were observed among the three groups with regard to patients' basic characteristics. Below IT, there were no differences in oxygen pulse/watt (O2 pulse increasing rate), HR/watt (ΔHR/ΔWR), and ΔV˙O2/ΔWR. Above IT, O2 pulse increasing rate was greater in Group A than in Group B. ΔHR/ΔWR was smaller in Group A than in Group B. ΔV˙O2/ΔWR became smaller in Group A than in Group B. There was no difference in anaerobic threshold, and peak V˙O2 was smaller in Group A than in Group B. Restriction of HR response by a BB is shown to be one of the important factors in diminished exercise tolerance. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  17. The Importance of Preserving Paper-Based Artifacts in a Digital Age

    Science.gov (United States)

    Bee, Robert

    2008-01-01

    The preservation of paper-based artifacts is an essential issue for collection management in academic libraries. In recent years, the library science profession has often favored reformatting through microfilm or digitization, assuming too quickly that information matters, whereas an artifact's medium does not. However, much recent humanities…

  18. Report of an International Workshop on Preserving Historic Buildings of Major Importance

    Science.gov (United States)

    1993-12-01

    visitors, deliberate damage caused by vandalism and graffiti , and benign neglect caused by lack of proper and consistent maintenance. Each member of...team of 28 professionals with expertise in the fields of seismology, geophysics, geotechnical and structural engineering, architecture, and art ...irreplaceable historic construction; develop an effective preservation strategy; advance the state-of-the- art techniques in engineering seismology

  19. Preserving and maintaining vital Ecosystem Services: the importance of linking knowledge from Geosciences and social-ecological System analysis

    Science.gov (United States)

    Finger, David; Petursdottir, Thorunn

    2013-04-01

    Human kind has always been curios and motivated to understand and quantify environmental processes in order to predict and anticipate the evolution of vital ecosystem services. Even the very first civilizations used empirical correlations to predict outcomes of rains and subsequent harvest efficiencies. Along with the insights into the functioning of ecosystems, humans also became aware that their anthropogenic activities can have positive and negative impact on ecosystem services. In recent years, geosciences have brought forward new sophisticated observations and modeling tools, with the aim to improve predictions of ecological developments. At the same time, the added value of linking ecological factors to the surrounding social structure has received a growing acceptance among scientists. A social-ecological system approach brings in a holistic understanding of how these systems are inevitably interlinked and how their sustainability can be better maintained. We claim that the biggest challenge for geoscience in the coming decades will be to link these two disciplines in order to establish adequate strategies to preserve natural ecosystems and their services, parallel to their utilization. We will present various case studies from more than a decade of research, ranging from water quality in mountain lakes, climate change impacts on water availability and declining fishing yields in freshwaters and discuss how the studies outcomes could be given added value by interpreting them via social-ecological system analysis. For instance, sophisticated field investigations revealed that deep water mixing in lake Issyk-Kul, Kirgizstan, is intensively distributing pollutants in the entire lake. Although fishery is an important sector in the region, the local awareness of the importance of water quality is low. In Switzerland, strict water protection laws led to ologotrophication of alpine lakes, reducing fishing yields. While local fishermen argued that local fishery is

  20. Preserving spatial linear correlations between neighboring stations in simulating daily precipitation using extended Markov models

    Science.gov (United States)

    Ababaei, Behnam; Sohrabi, Teymour; Mirzaei, Farhad

    2014-10-01

    Most stochastic weather generators have their focus on precipitation because it is the most important variable affecting environmental processes. One of the methods to reproduce the precipitation occurrence time series is to use a Markov process. But, in addition to the simulation of short-term autocorrelations in one station, it is sometimes important to preserve the spatial linear correlations (SLC) between neighboring stations as well. In this research, an extension of one-site Markov models was proposed to preserve the SLC between neighboring stations. Qazvin station was utilized as the reference station and Takestan (TK), Magsal, Nirougah, and Taleghan stations were used as the target stations. The performances of different models were assessed in relation to the simulation of dry and wet spells and short-term dependencies in precipitation time series. The results revealed that in TK station, a Markov model with a first-order spatial model could be selected as the best model, while in the other stations, a model with the order of two or three could be selected. The selected (i.e., best) models were assessed in relation to preserving the SLC between neighboring stations. The results depicted that these models were very capable in preserving the SLC between the reference station and any of the target stations. But, their performances were weaker when the SLC between the other stations were compared. In order to resolve this issue, spatially correlated random numbers were utilized instead of independent random numbers while generating synthetic time series using the Markov models. Although this method slightly reduced the model performances in relation to dry and wet spells and short-term dependencies, the improvements related to the simulation of the SLC between the other stations were substantial.

  1. Nature preservation acceptance model applied to tanker oil spill simulations

    DEFF Research Database (Denmark)

    Friis-Hansen, Peter; Ditlevsen, Ove Dalager

    2003-01-01

    is exemplified by a study of oil spills due to simulated tanker collisions in the Danish straits. It is found that the distribution of the oil spill volume per spill is well represented by an exponential distribution both in Oeresund and in Great Belt. When applied in the Poisson model, a risk profile reasonably...... close to the standard lognormal profile is obtained. Moreover, based on data pairs (volume, cost) for world wide oil spills it is inferred that the conditional distribution of the costs given the spill volume is well modeled by a lognormal distribution. By unconditioning by the exponential distribution...... of the single oil spill, a risk profile for the costs is obtained that is indistinguishable from the standard lognormal risk profile.Finally the question of formulating a public risk acceptance criterion is addressed following Ditlevsen, and it is argued that a Nature Preservation Willingness Index can...

  2. A Secure Privacy-Preserving Data Aggregation Model in Wearable Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Changlun Zhang

    2015-01-01

    Full Text Available With the rapid development and widespread use of wearable wireless sensors, data aggregation technique becomes one of the most important research areas. However, the sensitive data collected by sensor nodes may be leaked at the intermediate aggregator nodes. So, privacy preservation is becoming an increasingly important issue in security data aggregation. In this paper, we propose a security privacy-preserving data aggregation model, which adopts a mixed data aggregation structure. Data integrity is verified both at cluster head and at base station. Some nodes adopt slicing technology to avoid the leak of data at the cluster head in inner-cluster. Furthermore, a mechanism is given to locate the compromised nodes. The analysis shows that the model is robust to many attacks and has a lower communication overhead.

  3. Multi-resolution representation of digital terrain models with terrain features preservation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    multi-resolution TIN model is an important issue in the contexts of visu-alization,virtual reality (VR),and geographic information systems (GIS). This paper proposes a new method for constructing multi-resolution TIN models with multi-scale topographic features preservation. The proposed method is driven by a half-edge collapse operation in a greedy framework and employs a new quadric error metric to efficiently measure geometric errors. We define topographic features in a multi-scale manner using a center-surround operator on Gaussian-weighted mean curvatures. Experimental results demonstrate that the proposed method performs better than previous methods in terms of topographic features preservation,and is able to achieve multi-resolution TIN models with a higher accuracy.

  4. Comparison of lung preservation solutions in human lungs using an ex vivo lung perfusion experimental model

    Directory of Open Access Journals (Sweden)

    Israel L. Medeiros

    2012-09-01

    Full Text Available OBJECTIVE: Experimental studies on lung preservation have always been performed using animal models. We present ex vivo lung perfusion as a new model for the study of lung preservation. Using human lungs instead of animal models may bring the results of experimental studies closer to what could be expected in clinical practice. METHOD: Brain-dead donors whose lungs had been declined by transplantation teams were used. The cases were randomized into two groups. In Group 1, Perfadex®was used for pulmonary preservation, and in Group 2, LPDnac, a solution manufactured in Brazil, was used. An ex vivo lung perfusion system was used, and the lungs were ventilated and perfused after 10 hours of cold ischemia. The extent of ischemic-reperfusion injury was measured using functional and histological parameters. RESULTS: After reperfusion, the mean oxygenation capacity was 405.3 mmHg in Group 1 and 406.0 mmHg in Group 2 (p = 0.98. The mean pulmonary vascular resistance values were 697.6 and 378.3 dyn·s·cm-5, respectively (p =0.035. The mean pulmonary compliance was 46.8 cm H20 in Group 1 and 49.3 ml/cm H20 in Group 2 (p =0.816. The mean wet/dry weight ratios were 2.06 and 2.02, respectively (p=0.87. The mean Lung Injury Scores for the biopsy performed after reperfusion were 4.37 and 4.37 in Groups 1 and 2, respectively (p = 1.0, and the apoptotic cell counts were 118.75/mm² and 137.50/mm², respectively (p=0.71. CONCLUSION: The locally produced preservation solution proved to be as good as Perfadex®. The clinical use of LPDnac may reduce costs in our centers. Therefore, it is important to develop new models to study lung preservation.

  5. Preservation of benthic foraminifera and reliability of deep-sea temperature records: Importance of sedimentation rates, lithology, and the need to examine test wall structure

    Science.gov (United States)

    Sexton, Philip F.; Wilson, Paul A.

    2009-06-01

    Preservation of planktic foraminiferal calcite has received widespread attention in recent years, but the taphonomy of benthic foraminiferal calcite and its influence on the deep-sea palaeotemperature record have gone comparatively unreported. Numerical modeling indicates that the carbonate recrystallization histories of deep-sea sections are dominated by events in their early burial history, meaning that the degree of exchange between sediments and pore fluids during the early postburial phase holds the key to determining the palaeotemperature significance of diagenetic alteration of benthic foraminifera. Postburial sedimentation rate and lithology are likely to be important determinants of the paleoceanographic significance of this sediment-pore fluid interaction. Here we report an investigation of the impact of extreme change in sedimentation rate (a prolonged and widespread Upper Cretaceous hiatus in the North Atlantic Ocean) on the preservation and δ18O of benthic foraminifera of Middle Cretaceous age (nannofossil zone NC10, uppermost Albian/lowermost Cenomanian, ˜99 Ma ago) from multiple drill sites. At sites where this hiatus immediately overlies NC10, benthic foraminifera appear to display at least moderate preservation of the whole test. However, on closer inspection, these tests are shown to be extremely poorly preserved internally and yield δ18O values substantially higher than those from contemporaneous better preserved benthic foraminifera at sites without an immediately overlying hiatus. These high δ18O values are interpreted to indicate alteration close to the seafloor in cooler waters during the Late Cretaceous hiatus. Intersite differences in lithology modulate the diagenetic impact of this extreme change in sedimentation rate. Our results highlight the importance of thorough examination of benthic foraminiferal wall structures and lend support to the view that sedimentation rate and lithology are key factors controlling the paleoceanographic

  6. Structure-preserving model reduction of large-scale logistics networks. Applications for supply chains

    Science.gov (United States)

    Scholz-Reiter, B.; Wirth, F.; Dashkovskiy, S.; Makuschewitz, T.; Schönlein, M.; Kosmykov, M.

    2011-12-01

    We investigate the problem of model reduction with a view to large-scale logistics networks, specifically supply chains. Such networks are modeled by means of graphs, which describe the structure of material flow. An aim of the proposed model reduction procedure is to preserve important features within the network. As a new methodology we introduce the LogRank as a measure for the importance of locations, which is based on the structure of the flows within the network. We argue that these properties reflect relative importance of locations. Based on the LogRank we identify subgraphs of the network that can be neglected or aggregated. The effect of this is discussed for a few motifs. Using this approach we present a meta algorithm for structure-preserving model reduction that can be adapted to different mathematical modeling frameworks. The capabilities of the approach are demonstrated with a test case, where a logistics network is modeled as a Jackson network, i.e., a particular type of queueing network.

  7. Plastination and its importance in teaching anatomy. Critical points for long-term preservation of human tissue.

    Science.gov (United States)

    Riederer, Beat M

    2014-03-01

    Most medical curricula rely on human bodies for teaching macroscopic anatomy. Over the past 20 years, plastination has become an important means of preservation of organs, for well dissected specimens or for body slices. Here, several critical points regarding body donation with legal and ethical considerations for long-term preservation, the use of cadavers in teaching and the preparation of plastinates as an additional teaching tool will be discussed. Silicone S10 is the gold standard in the preparation of plastinates. An important point to respect is the preparation of specimens, since only very well dissected body parts or excellent tissue sections should be plastinated to show the extraordinary aspects of the human anatomy. The preparation of thin and transparent sections and preservation with P40 polyester provides an additional technique to prepare resistant body slices. A selection of samples prepared by S10 and P40 are shown and compared. In addition, Prussian or Berlin blue staining of brain slices is shown to discriminate better between gray and white matter and demonstrate neuroanatomical structures. These plastinates have been used for many years in teaching first- and second-year medical students and have not lost their appeal. Students and staff appreciate the use of such plastinates. One of the advantages is that their use is not restricted to the dissection hall; slices and body parts can be used in any lecture room or in small group teaching. Therefore, ethical and legal questions need to be addressed regarding their specific use. Plastinates do not replace the traditional dissection courses, since students learn best the anatomical features of a given region by hands-on dissection and by exploratory anatomy. Furthermore, plastinates are more rigid and do not allow demonstration of hidden structures; they also become more cumbersome for endoscopy or are too rigid for demonstrating mechanical features of joints. However, although not a replacement

  8. Importance of plan curvature in watershed modeling

    Science.gov (United States)

    Boll, J.; Ribail, J.; Zhao, M.

    2016-12-01

    A hillslope's hydrologic response to precipitation events is largely controlled by the topographic features of a given hillslope, specifically the profile and plan curvature. Many models simplify hillslope topography and ignore the curvature properties, and some use alternate measures such as a topographic index or the hillslope width function. Models that ignore curvature properties may be calibrated to produce the statistically acceptable integrated response of runoff at a watershed outlet, but incorporating these properties is necessary to model accurately hydrologic processes such as surface flow, erosion, subsurface lateral flow, location of runoff generation and drainage response. In this study, we evaluated the sensitivity of rainfall-runoff modelling to profile and plan curvature in two models. In the first model, the Water Erosion Prediction Project (WEPP) model, hillslope uses a representative width to the hillslope by dividing the drainage area by the average surface channel length. Profile curvature is preserved with a limited spatial resolution due to the number of overland flow elements. In the second model, the distributed Soil Moisture Routing (SMR) model, the geographic information system uses the D8 algorithm to capture profile and plan curvature. Sensitivity to topographic features was tested for three profile curvatures (convex, concave, straight) combined with three plan curvatures (diverging, converging, uniform) resulting in a total of nine hillslopes. Each hillslope was subjected to different rainfall events to detect threshold behavior for when topographic features cannot be ignored. Our findings indicate that concave and convex plan curvature need to be included when subsurface flow processes are the dominant flow process for surface flow runoff generation. We present thresholds for acceptable cases when profile and plan curvature can be simplified in larger spatial hydrologic units.

  9. Beyond Poiseuille: Preservation Fluid Flow in an Experimental Model

    Directory of Open Access Journals (Sweden)

    Saurabh Singh

    2013-01-01

    Full Text Available Poiseuille’s equation describes the relationship between fluid viscosity, pressure, tubing diameter, and flow, yet it is not known if cold organ perfusion systems follow this equation. We investigated these relationships in an ex vivo model and aimed to offer some rationale for equipment selection. Increasing the cannula size from 14 to 20 Fr increased flow rate by a mean (SD of 13 (12%. Marshall’s hyperosmolar citrate was three times less viscous than UW solution, but flows were only 45% faster. Doubling the bag pressure led to a mean (SD flow rate increase of only 19 (13%, not twice the rate. When external pressure devices were used, 100 mmHg of continuous pressure increased flow by a mean (SD of 43 (17% when compared to the same pressure applied initially only. Poiseuille’s equation was not followed; this is most likely due to “slipping” of preservation fluid within the plastic tubing. Cannula size made little difference over the ranges examined; flows are primarily determined by bag pressure and fluid viscosity. External infusor devices require continuous pressurisation to deliver high flow. Future studies examining the impact of perfusion variables on graft outcomes should include detailed equipment descriptions.

  10. [Comments on histopathology examinations in forensic medicine -- the importance, indications and basic principles of preserving the tissues].

    Science.gov (United States)

    Jankowski, Zbigniew; Pieśniak, Dorota

    2007-01-01

    Histopathology examinations and their usefulness in postmortem diagnosis and medico-legal expertise have always been regarded extremely important by the Faculty of the Chair and Department of Forensic Medicine at the Medical University of Gdansk. The authors postulate acceptance of indication criteria for histopathology examination in forensic autopsies and propose rules for collecting tissue samples from internal organs and the placenta. They also remind the readers of the principles of proceeding with the preserved material. The present paper may be helpful for doctors other than forensic pathologists, who perform autopsies in institutions other than university departments of forensic medicine.

  11. Importance Sampling for the Infinite Sites Model*

    OpenAIRE

    Hobolth, Asger; Uyenoyama, Marcy K; Wiuf, Carsten

    2008-01-01

    Importance sampling or Markov Chain Monte Carlo sampling is required for state-of-the-art statistical analysis of population genetics data. The applicability of these sampling-based inference techniques depends crucially on the proposal distribution. In this paper, we discuss importance sampling for the infinite sites model. The infinite sites assumption is attractive because it constraints the number of possible genealogies, thereby allowing for the analysis of larger data sets. We recall th...

  12. Animal models of heart failure with preserved ejection fraction

    NARCIS (Netherlands)

    G. Conceição; I. Heinonen (Ilkka); A.P. Lourenço; D.J.G.M. Duncker (Dirk); I. Falcão-Pires

    2016-01-01

    textabstractHeart failure with preserved ejection fraction (HFpEF) constitutes a clinical syndrome in which the diagnostic criteria of heart failure are not accompanied by gross disturbances of systolic function, as assessed by ejection fraction. In turn, under most circumstances, diastolic function

  13. A Privacy Preservation Model for Health-Related Social Networking Sites.

    Science.gov (United States)

    Li, Jingquan

    2015-07-08

    The increasing use of social networking sites (SNS) in health care has resulted in a growing number of individuals posting personal health information online. These sites may disclose users' health information to many different individuals and organizations and mine it for a variety of commercial and research purposes, yet the revelation of personal health information to unauthorized individuals or entities brings a concomitant concern of greater risk for loss of privacy among users. Many users join multiple social networks for different purposes and enter personal and other specific information covering social, professional, and health domains into other websites. Integration of multiple online and real social networks makes the users vulnerable to unintentional and intentional security threats and misuse. This paper analyzes the privacy and security characteristics of leading health-related SNS. It presents a threat model and identifies the most important threats to users and SNS providers. Building on threat analysis and modeling, this paper presents a privacy preservation model that incorporates individual self-protection and privacy-by-design approaches and uses the model to develop principles and countermeasures to protect user privacy. This study paves the way for analysis and design of privacy-preserving mechanisms on health-related SNS.

  14. A Privacy Preservation Model for Health-Related Social Networking Sites

    Science.gov (United States)

    2015-01-01

    The increasing use of social networking sites (SNS) in health care has resulted in a growing number of individuals posting personal health information online. These sites may disclose users' health information to many different individuals and organizations and mine it for a variety of commercial and research purposes, yet the revelation of personal health information to unauthorized individuals or entities brings a concomitant concern of greater risk for loss of privacy among users. Many users join multiple social networks for different purposes and enter personal and other specific information covering social, professional, and health domains into other websites. Integration of multiple online and real social networks makes the users vulnerable to unintentional and intentional security threats and misuse. This paper analyzes the privacy and security characteristics of leading health-related SNS. It presents a threat model and identifies the most important threats to users and SNS providers. Building on threat analysis and modeling, this paper presents a privacy preservation model that incorporates individual self-protection and privacy-by-design approaches and uses the model to develop principles and countermeasures to protect user privacy. This study paves the way for analysis and design of privacy-preserving mechanisms on health-related SNS. PMID:26155953

  15. Importance of animal models in schizophrenia research.

    Science.gov (United States)

    van den Buuse, M; Garner, B; Gogos, A; Kusljic, S

    2005-07-01

    This review aims to summarize the importance of animal models for research on psychiatric illnesses, particularly schizophrenia. Several aspects of animal models are addressed, including animal experimentation ethics and theoretical considerations of different aspects of validity of animal models. A more specific discussion is included on two of the most widely used behavioural models, psychotropic drug-induced locomotor hyperactivity and prepulse inhibition, followed by comments on the difficulty of modelling negative symptoms of schizophrenia. Furthermore, we emphasize the impact of new developments in molecular biology and the generation of genetically modified mice, which have generated the concept of behavioural phenotyping. Complex psychiatric illnesses, such as schizophrenia, cannot be exactly reproduced in species such as rats and mice. Nevertheless, by providing new information on the role of neurotransmitter systems and genes in behavioural function, animal 'models' can be an important tool in unravelling mechanisms involved in the symptoms and development of such illnesses, alongside approaches such as post-mortem studies, cognitive and psychophysiological studies, imaging and epidemiology.

  16. Animal models of heart failure with preserved ejection fraction

    OpenAIRE

    Conceição, G.; Heinonen, I.; Lourenço, A. P.; Duncker, D. J.; Falcão-Pires, I.

    2016-01-01

    Heart failure with preserved ejection fraction (HFpEF) constitutes a clinical syndrome in which the diagnostic criteria of heart failure are not accompanied by gross disturbances of systolic function, as assessed by ejection fraction. In turn, under most circumstances, diastolic function is impaired. Although it now represents over 50 % of all patients with heart failure, the mechanisms of HFpEF remain understood, precluding effective therapy. Understanding the pathophysiology of HFpEF has be...

  17. Animal models: an important tool in mycology.

    Science.gov (United States)

    Capilla, Javier; Clemons, Karl V; Stevens, David A

    2007-12-01

    Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

  18. Testing the molecular clock using mechanistic models of fossil preservation and molecular evolution

    Science.gov (United States)

    2017-01-01

    Molecular sequence data provide information about relative times only, and fossil-based age constraints are the ultimate source of information about absolute times in molecular clock dating analyses. Thus, fossil calibrations are critical to molecular clock dating, but competing methods are difficult to evaluate empirically because the true evolutionary time scale is never known. Here, we combine mechanistic models of fossil preservation and sequence evolution in simulations to evaluate different approaches to constructing fossil calibrations and their impact on Bayesian molecular clock dating, and the relative impact of fossil versus molecular sampling. We show that divergence time estimation is impacted by the model of fossil preservation, sampling intensity and tree shape. The addition of sequence data may improve molecular clock estimates, but accuracy and precision is dominated by the quality of the fossil calibrations. Posterior means and medians are poor representatives of true divergence times; posterior intervals provide a much more accurate estimate of divergence times, though they may be wide and often do not have high coverage probability. Our results highlight the importance of increased fossil sampling and improved statistical approaches to generating calibrations, which should incorporate the non-uniform nature of ecological and temporal fossil species distributions. PMID:28637852

  19. A Model of Women Literacy Preservation through Koran Ibu Program

    Directory of Open Access Journals (Sweden)

    Ikka Kartika Abbas Fauzi

    2016-08-01

    Full Text Available The effect of literacy education is often disappointing, because many participants do not practice their literacy so that it becomes dull. Government has done efforts to preserve literariness through Koran Ibu program. This program is an effort to improve women literacy which is implemented after basic and advanced literacy education through the activity of journalism. The research focus is the improvement of literacy ability of women through Koran Ibu using with case study method. The research’s subjetcs are 20 housewives who have completed the basic and advanced literacy education program. The result of the research shows that participants significantly develops the literacy skills, it is indicated from that they are able to participate in Koran Ibu’s rubrics with their literary works based on reportage and personal experience. The program is succesful due to the coordination among  local participants (Lurah, Camat, PKK of local level, the cooperation with proper stakeholders (university and local tutor, the appropriate approach of adult learning, flexible implementation strategy but planned, and the routine evaluation.

  20. Dissipativity preserving model reduction by retention of trajectories of minimal dissipation

    NARCIS (Netherlands)

    Trentelman, Harry L.; Ha Binh Minh, [No Value; Rapisarda, Paolo

    2009-01-01

    We present a method for model reduction based on ideas from the behavioral theory of dissipative systems, in which the reduced order model is required to reproduce a subset of the set of trajectories of minimal dissipation of the original system. The passivity-preserving model reduction method of An

  1. Evaluation of IGL-1 preservation solution using an orthotopic liver transplantation model

    Institute of Scientific and Technical Information of China (English)

    Hassen Ben Abdennebi; Ziad Elrassi; Jean-Yves Scoazec; Jean-Paul Steghens; Silvina Ramella-Virieux; Olivier Boillot

    2006-01-01

    AIM: To compare, in a pig liver transplantation model,the protective effect of UW with that of IGL-1, a highsodium preservation solution containing polyethylene glycol (PEG) as an oncotic supply.METHODS: All livers were harvested and grafted orthotopically according to standard techniques. The livers were washed out and preserved for 7 h in IGL-1 (n = 6) or in UW solution (n = 7) at 4℃. In a sham group (n = 4), the livers underwent a 60-min warm ischemia at 37℃. The hepatocellular injury was assessed in organ preservation solution washed out from the graft at the end of ischemic storage (before revascularization), and in serum 2 h after reperfusion and daily for up to 6 d.RESULTS: Livers preserved in IGL-1 solution released markedly less AST than that preserved in the UW solution before and after revascularization (P < 0.05).Besides, the activity of creatine kinase-BB, a marker of sinusoidal lining cells injury, was higher in the UW group than in the IGL-1 group (P < 0.05). Histological results showed less necrotic regions in livers preserved in IGL-1 solution; however, no difference was observed for inflammation.CONCLUSION: IGL-1 liquid effectively protects parenchymal and non-parenchymal cells against preservation-reperfusion injuries.

  2. Model regularization for seismic traveltime tomography with an edge-preserving smoothing operator

    Science.gov (United States)

    Zhang, Xiong; Zhang, Jie

    2017-03-01

    The solutions of the seismic first-arrival traveltime tomography are generally non-unique, and the Tikhonov model regularization for the inversion is commonly used to stabilize the inversion. However, the Tikhonov regularization for traveltime tomography often produces a low-resolution velocity model. To sharpen the velocity edges for the traveltime tomographic results and fit data at the same time, we should apply the edge-preserving concepts to regularize the inversion. In this study, we develop a new model regularization method by introducing an edge-preserving smoothing operator to detect the model edges in traveltime tomography. This edge-preserving smoothing operator is previously used in processing seismic images for enhancing resolution. We design three synthetic velocity models with sharp interfaces and with or without velocity gradients to study the performance of the regularization method with the edge-preserving smoothing operator. The new edge-preserving regularization not only sharpens the model edges but also maintains the smoothness of the velocity gradient in the layer.

  3. How much does it cost? The LIFE Project - Costing Models for Digital Curation and Preservation

    Directory of Open Access Journals (Sweden)

    Richard Davies

    2007-11-01

    Full Text Available Digital preservation is concerned with the long-term safekeeping of electronic resources. How can we be confident of their permanence, if we do not know the cost of preservation? The LIFE (Lifecycle Information for E-Literature Project has made a major step forward in understanding the long-term costs in this complex area. The LIFE Project has developed a methodology to model the digital lifecycle and to calculate the costs of preserving digital information for the next 5, 10 or 100 years. National and higher education (HE libraries can now apply this process and plan effectively for the preservation of their digital collections. Based on previous work undertaken on the lifecycles of paper-based materials, the LIFE Project created a lifecycle model and applied it to real-life digital collections across a diverse subject range. Three case studies examined the everyday operations, processes and costs involved in their respective activities. The results were then used to calculate the direct costs for each element of the digital lifecycle. The Project has made major advances in costing preservation activities, as well as making detailed costs of real digital preservation activities available. The second phase of LIFE (LIFE2, which recently started, aims to refine the lifecycle methodology and to add a greater range and breadth to the project with additional exemplar case studies.

  4. Non-uniform force allocation for area preservation in spring network models

    CERN Document Server

    Cimrak, Ivan

    2016-01-01

    In modelling of elastic objects in a flow such as red blood cells, white blood cells, or tumour cells, several elastic moduli are involved. One of them is the area conservation modulus. In this paper, we focus on spring network models and we introduce a new way of modeling the area preservation modulus. We take into account the current shape of the individual triangles and find the proportional allocation of area conservation forces, which would for individual triangles preserve their shapes. The analysis shows that this approach tends to regularize the triangulation. We demonstrate this effect on individual triangles as well as on the complete triangulations.

  5. A morphologically preserved multi-resolution TIN surface modeling and visualization method for virtual globes

    Science.gov (United States)

    Zheng, Xianwei; Xiong, Hanjiang; Gong, Jianya; Yue, Linwei

    2017-07-01

    Virtual globes play an important role in representing three-dimensional models of the Earth. To extend the functioning of a virtual globe beyond that of a ;geobrowser;, the accuracy of the geospatial data in the processing and representation should be of special concern for the scientific analysis and evaluation. In this study, we propose a method for the processing of large-scale terrain data for virtual globe visualization and analysis. The proposed method aims to construct a morphologically preserved multi-resolution triangulated irregular network (TIN) pyramid for virtual globes to accurately represent the landscape surface and simultaneously satisfy the demands of applications at different scales. By introducing cartographic principles, the TIN model in each layer is controlled with a data quality standard to formulize its level of detail generation. A point-additive algorithm is used to iteratively construct the multi-resolution TIN pyramid. The extracted landscape features are also incorporated to constrain the TIN structure, thus preserving the basic morphological shapes of the terrain surface at different levels. During the iterative construction process, the TIN in each layer is seamlessly partitioned based on a virtual node structure, and tiled with a global quadtree structure. Finally, an adaptive tessellation approach is adopted to eliminate terrain cracks in the real-time out-of-core spherical terrain rendering. The experiments undertaken in this study confirmed that the proposed method performs well in multi-resolution terrain representation, and produces high-quality underlying data that satisfy the demands of scientific analysis and evaluation.

  6. Preservation engineering assets developed from an oxidation predictive model

    Directory of Open Access Journals (Sweden)

    Coutelieris Frank A.

    2016-01-01

    Full Text Available A previously developed model which effectively predicts the probability of olive oil reaching the end of its shelf-life within a certain time frame was tested for its response when the convective diffusion of oxygen through packaging material is taken in account. Darcy’s Law was used to correlate the packaging permeability with the oxygen flow through the packaging materials. Mass transport within the food-packaging system was considered transient and the relative one-dimensional differential equations along with appropriate initial and boundary conditions were numerically solved. When the Peclet (Pe number was used to validate the significance of the oxygen transport mechanism through packaging, the model results confirmed the Arrhenius type dependency of diffusion, where the slope of the line per material actually indicated their –Ea/R. Furthermore, Pe could not be correlated to the hexanal produced in samples stored under light. Photo-oxidation has a significant role in the oxidative degradation of olive oil confirmed by the shelf-assessing test. The validity of our model for the oxygen diffusion driven systems, was also confirmed, for that reason the predictive boundaries were set. Results safely indicated the significance of applying a self-assessing process to confirm the packaging selection process for oxygen sensitive food via this model.

  7. Passivity Preserving Model Order Reduction For the SMIB

    NARCIS (Netherlands)

    Ionescu, Tudor C.; Scherpen, Jacquelien M. A.

    2008-01-01

    We apply (linear) positive real balancing to the model of a single machine connected to an infinite bus. For that we compute the available storage and the required supply using Taylor approximation and define axis positive real singular value functions. Furthermore, we apply linear positive real bal

  8. Remarkable preservation of microbial mats in Neoproterozoic siliciclastic settings: Implications for Ediacaran taphonomic models

    Science.gov (United States)

    Callow, Richard H. T.; Brasier, Martin D.

    2009-10-01

    It is beyond doubt that the appearance of infaunal bioturbation and metazoan biomineralization across the Ediacaran-Cambrian transition irreversibly affected the nature of marine sediment architecture and biogeochemistry. Here we review those changes in relation to their likely effect upon the processes of fossil preservation, especially within siliciclastic sediments. Processes of soft-tissue preservation in siliciclastic settings from the Ediacaran Period, including microbes and microbial mats as well as Ediacaran macrofossils, are here reviewed within this context. Highlighted examples include the exceptional preservation of microbes found in association with wrinkle structures and Ediacaran macrofossils in England and Newfoundland (replicated by silicate minerals) and in the White Sea region of Russia (replicated by iron sulphide). These occurrences show that soft-tissue preservation in siliciclastic settings went well beyond that typical for Ediacaran macrofossils alone and also extended to similar modes of preservation in associated microbes. Using these new observations it can be argued that several existing explanations for Ediacaran fossil preservation can be united within a biogeochemical model that involves evolution of the sediment mixed layer across this transition.

  9. 4D Shape-Preserving Modelling of Bone Growth

    DEFF Research Database (Denmark)

    Andresen, Per Rønsholt; Nielsen, Mads; Kreiborg, Sven

    1998-01-01

    From a set of temporally separated scannings of the same anatomical structure we wish to identify and analyze the growth in terms of a metamorphosis. That is, we study the tempral change of shape which may prowide an understanding of the biological processes which govern the growth process. We...... subdivide the growth analysis into growth simulation, growth modelling, and finally the growth analysis. In this paper, we present results of growth simulation of the mandible from 3 scannings of the same patient in the age of 9 months, 21 months, and 7 years. We also present the first growth models...... and growth analyzes. The ultimative goal is to predict/simulate human growth which would be extremely useful in many surgical procedures....

  10. Evaluation of CMU-1 preservation solutions using an isolated perfused rat liver model

    Institute of Scientific and Technical Information of China (English)

    Ying Cheng; Yong-Feng Liu; Dong-Hua Cheng; Bai-Feng Li; Ning Zhao

    2005-01-01

    AIM: CMU-1 is a new preservation solution with a low potassium concentration as well as low viscosity that is highly effective in reducing preservation injury. The purpose of this experiment is to compare the protective effect of CMU-1 solution with that of UW during cold presevation and normothermic reperfusion.METHODS: Wistar rats were divided into two groups according to different preservation solution: CMU-1 group and UW group. After 6, 12 and 24 h cold storage of rat liver in different preservation solutions, the isolated perfused rat liver model was applied to reperfuse the liver for 120 min normothermically (37 ℃) with KrebsHenseleit solution, meanwhile the pH value of the preservation solution was measured. The perfusate was sampled for the evaluation of alanine aminotransferase (ALT) and lactate dehydrogenase (LDH). At the end of the reperfusion, all of the bile product was collected, energy metabolic substrate and histological examination were performed.RESULTS: After preserving for 6 h, pH value of both groups did not change; after 12 h, both decreased but with no significant difference. After 24 h, pH value in UW solution group significantly decreased. The total adenine nudeotides level and AEC in liver tissue decreased with preservation time, but they were higher in CMU-1 group. And the amount of bile product after perfusion for 120 min in CMU-1 group was much more than that in UW group. However,there were no significant differences in ALT and LDH levels between two groups. Histology showed no difference.CONCLUSION: The preservation effect of CMU-1 solution is similar with that of UW solution. However, CMU-1 solution shows some advantages over UW solution in energy metabolism, preventing intracellular acidosis and bile product.

  11. How craton margins are preserved: Insights from geodynamic models

    Science.gov (United States)

    Currie, Claire A.; van Wijk, Jolante

    2016-10-01

    Lateral variations in lithosphere thickness are observed in many continental regions, especially at the boundary between the ancient cratonic core and the adjacent more juvenile lithosphere. In some places, such as the North America craton margin in western Canada and the Sorgenfrei-Tornquist Zone in northern Europe, the transition in lithosphere thickness has a steep gradient (>45°) and it appears to be a long-lived feature (at least 50 Ma). We use thermal-mechanical numerical models to address the dynamics of lithospheric thickness changes on timescales of 100 Ma. Models start with the juxtaposition of 60 km thick lithosphere ("mobile belt") and 160 km thick lithosphere ("craton"). In the reference model, all mantle materials have a damp olivine rheology and a density comparable to primitive mantle. With this configuration, edge-driven mantle convection occurs at the craton boundary, resulting in a lateral smoothing of the thickness transition. The density and rheology of the craton mantle lithosphere are then varied to approximate changes in composition and water content. For all densities, a steep transition is maintained only if the craton strength is 5-50 times stronger than the reference damp olivine. If dry olivine is an upper limit on strength, only cratonic mantle with moderate compositional buoyancy (20-40 kg/m3 less dense than primitive mantle) remains stable. At higher densities, the thick lithosphere is eroded through downwellings, and the craton margin migrates inboard. Conversely, a compositionally buoyant craton destabilises through lateral spreading below the mobile belt.

  12. Model of evaluating the projected payback period in energy preservation

    Directory of Open Access Journals (Sweden)

    Gorshkov Aleksandr Sergeevich

    2015-12-01

    Full Text Available Providing energy efficiency of newly designed buildings is an important state task which is considered in EPBD directive and the latest regulations on energy saving. Though reducing energy consumption of the existing building is not less important. The majority of the existing buildings had been built before the implementation of modern energy saving programs. That’s why the volume of energy consumption in the existing buildings is greater than in new buildings. In frames of the given investigation the author considers the problem of forecasting the payback period of investment into reduction of energy consumption in a building. The formula is offered for calculating the projected payback period in energy saving with account for capital costs, calculated or actual value of the achieved energy saving effect, rise in tariffs for energy sources, discounting of the future cash flows and the volume and time for return of credit funds. Basing on the offered calculation methods it is possible to compare the efficiency of different energy saving solutions.

  13. Near-Infrared Coloring via a Contrast-Preserving Mapping Model.

    Science.gov (United States)

    Son, Chang-Hwan; Zhang, Xiao-Ping

    2017-11-01

    Near-infrared gray images captured along with corresponding visible color images have recently proven useful for image restoration and classification. This paper introduces a new coloring method to add colors to near-infrared gray images based on a contrast-preserving mapping model. A naive coloring method directly adds the colors from the visible color image to the near-infrared gray image. However, this method results in an unrealistic image because of the discrepancies in the brightness and image structure between the captured near-infrared gray image and the visible color image. To solve the discrepancy problem, first, we present a new contrast-preserving mapping model to create a new near-infrared gray image with a similar appearance in the luminance plane to the visible color image, while preserving the contrast and details of the captured near-infrared gray image. Then, we develop a method to derive realistic colors that can be added to the newly created near-infrared gray image based on the proposed contrast-preserving mapping model. Experimental results show that the proposed new method not only preserves the local contrast and details of the captured near-infrared gray image, but also transfers the realistic colors from the visible color image to the newly created near-infrared gray image. It is also shown that the proposed near-infrared coloring can be used effectively for noise and haze removal, as well as local contrast enhancement.

  14. Digital preservation

    CERN Document Server

    Deegan, Marilyn

    2013-01-01

    Digital preservation is an issue of huge importance to the library and information profession right now. With the widescale adoption of the internet and the rise of the world wide web, the world has been overwhelmed by digital information. Digital data is being produced on a massive scale by individuals and institutions: some of it is born, lives and dies only in digital form, and it is the potential death of this data, with its impact on the preservation of culture, that is the concern of this book. So how can information professionals try to remedy this? Digital preservation is a complex iss

  15. Semantic Importance Sampling for Statistical Model Checking

    Science.gov (United States)

    2015-01-16

    approach called Statistical Model Checking (SMC) [16], which relies on Monte - Carlo -based simulations to solve this verification task more scalably...Conclusion Statistical model checking (SMC) is a prominent approach for rigorous analysis of stochastic systems using Monte - Carlo simulations. In this... Monte - Carlo simulations, for computing the bounded probability that a specific event occurs during a stochastic system’s execution. Estimating the

  16. Accuracy Enhanced Stability and Structure Preserving Model Reduction Technique for Dynamical Systems with Second Order Structure

    DEFF Research Database (Denmark)

    Tahavori, Maryamsadat; Shaker, Hamid Reza

    A method for model reduction of dynamical systems with the second order structure is proposed in this paper. The proposed technique preserves the second order structure of the system, and also preserves the stability of the original systems. The method uses the controllability and observability...... gramians within the time interval to build the appropriate Petrov-Galerkin projection for dynamical systems within the time interval of interest. The bound on approximation error is also derived. The numerical results are compared with the counterparts from other techniques. The results confirm...

  17. Thermodynamic investigation of the interaction between cyclodextrins and preservatives - Application and verification in a mathematical model to determine the needed preservative surplus in aqueous cyclodextrin formulations

    DEFF Research Database (Denmark)

    Holm, René; Olesen, Niels Erik; Alexandersen, Signe Dalgaard

    2016-01-01

    of the present work was to establish a mathematical model, which defines this surplus based upon knowledge of stability constants and the minimal concentration of preservation to inhibit bacterial growth. The stability constants of benzoic acid, methyl- and propyl-paraben with different frequently used βCDs were...

  18. Controls on sequence development and preservation offshore Namibia: Implications for sequence stratigraphic models and hydrocarbon prediction

    Energy Technology Data Exchange (ETDEWEB)

    Bagguley, J.G. [Oxford Brookes Univ., Oxford (United Kingdom); Prosser, S. [Saga Petroleum, Sandvika (Norway)

    1996-12-31

    Regional seismic interpretation of the passive margin offshore Namibia has enabled a sequence stratigraphic framework to be established for this previously under-studied region. Within this framework potential hydrocarbon plays, for example the location of source, seal and reservoir rocks can be pinpointed. The history of sequence stratigraphic models suggests that the passive margin offshore Namibia should provide an ideal setting for applying and testing sequence stratigraphic concepts. Results from this study however suggest that alongside the documented controls in sequence stratigraphy (i.e. tectonics, eustacy and sediment flux), additional factors act to influence sequence development and preservation along this margin. Detailed seismic interpretation of the post rift section of the Namibian margin has led to the identification of a member of erosional and depositional events; for example, charmers, canyons and slumps. Seismic facies analysis allows causative mechanisms to be inferred for the different geometries observed. In addition, the recognition of characteristic seismic facies enables reservoir and non-reservoir targets to be identified, thus aiding the prediction of potential hydrocarbon plays. Backstripping studies provide further information as to the evolution of the Namibian margin. For example, estimates can be made regarding changes in the rates of tectonics and sedimentation and the relative importance of these factors on the development of the margin can be assessed.

  19. Controls on sequence development and preservation offshore Namibia: Implications for sequence stratigraphic models and hydrocarbon prediction

    Energy Technology Data Exchange (ETDEWEB)

    Bagguley, J.G. (Oxford Brookes Univ., Oxford (United Kingdom)); Prosser, S. (Saga Petroleum, Sandvika (Norway))

    1996-01-01

    Regional seismic interpretation of the passive margin offshore Namibia has enabled a sequence stratigraphic framework to be established for this previously under-studied region. Within this framework potential hydrocarbon plays, for example the location of source, seal and reservoir rocks can be pinpointed. The history of sequence stratigraphic models suggests that the passive margin offshore Namibia should provide an ideal setting for applying and testing sequence stratigraphic concepts. Results from this study however suggest that alongside the documented controls in sequence stratigraphy (i.e. tectonics, eustacy and sediment flux), additional factors act to influence sequence development and preservation along this margin. Detailed seismic interpretation of the post rift section of the Namibian margin has led to the identification of a member of erosional and depositional events; for example, charmers, canyons and slumps. Seismic facies analysis allows causative mechanisms to be inferred for the different geometries observed. In addition, the recognition of characteristic seismic facies enables reservoir and non-reservoir targets to be identified, thus aiding the prediction of potential hydrocarbon plays. Backstripping studies provide further information as to the evolution of the Namibian margin. For example, estimates can be made regarding changes in the rates of tectonics and sedimentation and the relative importance of these factors on the development of the margin can be assessed.

  20. Importance of maintaining left gastric arterial flow at Appleby operation preserving whole stomach for central pancreatic cancer.

    Science.gov (United States)

    Kimura, Akifumi; Yamamoto, Junji; Aosasa, Suefumi; Hatsuse, Kazuo; Nishikawa, Makoto; Nishiyama, Kiyoshi; Tsujimoto, Hironori; Moriya, Tomoyuki; Hase, Kazuo; Shinmoto, Hiroshi; Kaji, Tatsumi

    2012-01-01

    The safety of whole stomach-preserving Appleby operation with resection of the left gastric artery (LGA) for pancreatic cancer cannot be assured. The anatomy of the celiac axis (CA) with special regard to the position of the origin of the LGA was examined. Using 3D images of the vascular architecture reconstructed from volume data of helical CT, the length of the CA and the position of the origin of the LGA from the CA were measured in 53 patients. Among 53 patients, 47 patients (89%) had classical anatomy of the CA branches. The mean length(2 standard deviation) of the CA and the distance from the root of the LGA to the bifurcation of the CA were 25.2mm (-4.9) (range 14.6-36.5) and 10.3mm (+4.5)(range 2.4-21.9), respectively. In 23 (45%) cases, the LGA arose farther than 10mm away from the bifurcation of the CA. Among six patients with anatomical variation of the arteries, two (4%) had the LGA directly arising from the aorta. Conservation of the LGA at modified Appleby operation would give complete cancer removal by en bloc resection of the nerve plexus, without risk of ischemic complications of the stomach and liver.

  1. New strategies for heart failure with preserved ejection fraction: the importance of targeted therapies for heart failure phenotypes.

    Science.gov (United States)

    Senni, Michele; Paulus, Walter J; Gavazzi, Antonello; Fraser, Alan G; Díez, Javier; Solomon, Scott D; Smiseth, Otto A; Guazzi, Marco; Lam, Carolyn S P; Maggioni, Aldo P; Tschöpe, Carsten; Metra, Marco; Hummel, Scott L; Edelmann, Frank; Ambrosio, Giuseppe; Stewart Coats, Andrew J; Filippatos, Gerasimos S; Gheorghiade, Mihai; Anker, Stefan D; Levy, Daniel; Pfeffer, Marc A; Stough, Wendy Gattis; Pieske, Burkert M

    2014-10-21

    The management of heart failure with reduced ejection fraction (HF-REF) has improved significantly over the last two decades. In contrast, little or no progress has been made in identifying evidence-based, effective treatments for heart failure with preserved ejection fraction (HF-PEF). Despite the high prevalence, mortality, and cost of HF-PEF, large phase III international clinical trials investigating interventions to improve outcomes in HF-PEF have yielded disappointing results. Therefore, treatment of HF-PEF remains largely empiric, and almost no acknowledged standards exist. There is no single explanation for the negative results of past HF-PEF trials. Potential contributors include an incomplete understanding of HF-PEF pathophysiology, the heterogeneity of the patient population, inadequate diagnostic criteria, recruitment of patients without true heart failure or at early stages of the syndrome, poor matching of therapeutic mechanisms and primary pathophysiological processes, suboptimal study designs, or inadequate statistical power. Many novel agents are in various stages of research and development for potential use in patients with HF-PEF. To maximize the likelihood of identifying effective therapeutics for HF-PEF, lessons learned from the past decade of research should be applied to the design, conduct, and interpretation of future trials. This paper represents a synthesis of a workshop held in Bergamo, Italy, and it examines new and emerging therapies in the context of specific, targeted HF-PEF phenotypes where positive clinical benefit may be detected in clinical trials. Specific considerations related to patient and endpoint selection for future clinical trials design are also discussed. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  2. Neuronavigated Fiber Dissection with Pial Preservation: Laboratory Model to Simulate Opercular Approaches to Insular Tumors.

    Science.gov (United States)

    Mandonnet, Emmanuel; Martino, Juan; Sarubbo, Silvio; Corrivetti, Francesco; Bouazza, Schahrazed; Bresson, Damien; Duffau, Hugues; Froelich, Sebastien

    2017-02-01

    Advances in the oncologic and functional results of insular surgery have been reported recently. Such successes have been made possible by the advent of the transopercular approach under awake monitoring and by improved anatomic and functional knowledge of white matter pathways surrounding the insula. Nonetheless, given the rarity of insular tumors, it is difficult to get familiar with the complex 3-dimensional anatomy of the different neuronal and vascular structures encountered during a transopercular insular resection. We thus propose to develop a laboratory model allowing to train transopercular approaches of the insula. Two hemispheres prepared with Klinger's technique were dissected under light microscope, preserving all pial membranes. The different steps of the dissection were video recorded. Preservation of pial membranes enabled us to simulate subpial resection, both during operculum removal and during insular cortex resection. The medial wall of the resection was defined by the inferior-fronto-occipital fasciculus, protecting from the lenticulostriate arteries. In this paper, we show that Klinger dissection with preservation of pial membranes provides a realistic model of insular surgery, allowing surgeons to learn and train on this highly specialized surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Comparison between cryopreserved and glycerol-preserved allografts in a partial-thickness porcine wound model.

    Science.gov (United States)

    Yoon, Cheonjae; Lim, Kihwan; Lee, Sungjun; Choi, Yanghwan; Choi, Youngwhan; Lee, Jungsuk

    2016-03-01

    Human skin allografts are one of the best temporary biological coverings for severely burned patients. Cryopreserved (CPA) and glycerol-preserved (GPA) allografts are the most widely used types. This study compared the allograft efficiency of both preservation methods under the same conditions. To simulate actual clinical conditions, we used a porcine wound model. In addition, we evaluated the macroscopic and microscopic scoring of graft performance for each method. Porcine cadaver skin 1 mm thick was obtained from one pig. Cryopreserved skin cell viability was 20.8 %, glycerol-preserved skin was 9.08 %, and fresh skin was 58.6 %. We made ten partial-thickness wounds each in two pigs. The take rates on day 2 were 96.23 and 82.65 % in the GPA and CPA group (both n = 9), respectively. After 1 week, the take rates of both groups were nearly equal. The removal rate at week 5 was 98.87 and 94.41 % in the GPA and CPA group, respectively. On microscopic findings at week 2, inflammation was greater in the CPA group. Other findings such as fibroblast hyperplasia and neovascularization were not significantly different between both groups. At week 5, the score of collagen fiber synthesis was 2.67 ± 0.47 and 2.33 ± 0.47 in the GPA and CPA group, respectively. The epidermal-dermal junction was 2.22 ± 0.79 and 2.00 ± 0.47 in the GPA and CPA group, respectively. These findings suggest that wound healing takes longer in the CPA group. The preservation method of allografts is not a absolute factor in the wound healing process in this wound model.

  4. Results of a modeling workshop concerning preservation and protection of wetlands in North Dakota

    Science.gov (United States)

    Andrews, Austin K.; Auble, Gregor T.; Ellison, Richard A.; Hamilton, David B.; Roelle, James E.

    1981-01-01

    In a recently signed letter, the Governor of North Dakota and the Assistant Secretary of the Interior for Fish and Wildlife and Parks charged a joint state-federal study group with examination of two separate questions: 1) mitigation for the Garrison Diversion Project; and 2) planning for long-range protection and preservation of fish and wildlife habitat in North Dakota. The cochair for this study group (the Secretary of the Interior's Field Representative, Denver, Colorado, and the Natural Resources Coordinator for North Dakota) further articulated the charge concerning the second of these two questions to include three steps: 1) development of a general plan for preservation and protection of migratory waterfowl and their associated wetland habitat; 2) a comprehensive analysis of alternative strategies, including opportunities and constraints, for achieving the goals articulated in Step 1; and 3) design of a coordinated state-federal public information program to assist in plan implementation. In order to obtain input from a variety of interests, the joint study group initiated step 2 activities with a five-day workshop in Bismarck, N. D.; December 8-12, 1980. The objectives of the workshop were: 1) to identify alternative strategies for preserving and enhancing waterfowl production habitat in North Dakota; 2) to identify opportunities and constraints associated with those alternatives; and 3) to promote communication and understanding of the implications of those alternatives for all affected parties. To achieve these objectives, the workshop utilized a group of concepts and techniques collectively known as Adaptive Environmental Assessment (AEA). Developed by Dr. C. S. Holling and his co-workers at the University of British Columbia, the AEA process involves planners, managers, scientists, and other interested parties in a structures atmosphere whose focus is the construction and examination of a computerized simulation model of the resource system under

  5. Rank-preserving regression: a more robust rank regression model against outliers.

    Science.gov (United States)

    Chen, Tian; Kowalski, Jeanne; Chen, Rui; Wu, Pan; Zhang, Hui; Feng, Changyong; Tu, Xin M

    2016-08-30

    Mean-based semi-parametric regression models such as the popular generalized estimating equations are widely used to improve robustness of inference over parametric models. Unfortunately, such models are quite sensitive to outlying observations. The Wilcoxon-score-based rank regression (RR) provides more robust estimates over generalized estimating equations against outliers. However, the RR and its extensions do not sufficiently address missing data arising in longitudinal studies. In this paper, we propose a new approach to address outliers under a different framework based on the functional response models. This functional-response-model-based alternative not only addresses limitations of the RR and its extensions for longitudinal data, but, with its rank-preserving property, even provides more robust estimates than these alternatives. The proposed approach is illustrated with both real and simulated data. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Surrogate modelling and optimization using shape-preserving response prediction: A review

    Science.gov (United States)

    Leifsson, Leifur; Koziel, Slawomir

    2016-03-01

    Computer simulation models are ubiquitous in modern engineering design. In many cases, they are the only way to evaluate a given design with sufficient fidelity. Unfortunately, an added computational expense is associated with higher fidelity models. Moreover, the systems being considered are often highly nonlinear and may feature a large number of designable parameters. Therefore, it may be impractical to solve the design problem with conventional optimization algorithms. A promising approach to alleviate these difficulties is surrogate-based optimization (SBO). Among proven SBO techniques, the methods utilizing surrogates constructed from corrected physics-based low-fidelity models are, in many cases, the most efficient. This article reviews a particular technique of this type, namely, shape-preserving response prediction (SPRP), which works on the level of the model responses to correct the underlying low-fidelity models. The formulation and limitations of SPRP are discussed. Applications to several engineering design problems are provided.

  7. Modeling and predicting the growth boundary of Listeria monocytogenes in lightly preserved seafood

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Dalgaard, Paw

    2007-01-01

    in lightly preserved seafood. The developed growth boundary model accurately predicted growth and no-growth responses in 68 of 71 examined experiments from the present study as well as from literature data. Growth was predicted for three batches of naturally contaminated cold-smoked salmon when a no...... of products was explained by a higher content of naturally occurring lactate in cold-smoked salmon (0.77 to 0.98%, wt/ wt) than in cold-smoked Greenland halibut (0.10 to 0.15%, wt/wt). In fact, the addition of 0.15% (wt/wt) diacetate and 0.75% (wt/wt) lactate to MAP cold-smoked Greenland halibut prevented......-growth response was actually observed, indicating that the model is fail-safe. The developed model predicts both the growth boundary and growth rate of L. monocytogenes and seems useful for the risk management of lightly preserved seafood. Particularly, the model facilitates the identification of product...

  8. Dannie Heineman Prize for Mathematical Physics Prize Lecture: Correlation Functions in Integrable Models: Ising Model and Monodromy Preserving Deformation

    Science.gov (United States)

    Miwa, Tetsuji

    2013-03-01

    Studies on integrable models in statistical mechanics and quantum field theory originated in the works of Bethe on the one-dimensional quantum spin chain and the work of Onsager on the two-dimensional Ising model. I will talk on the discovery in 1977 of the link between quantum field theory in the scaling limit of the two-dimensional Ising model and the theory of monodromy preserving linear ordinary differential equations. This work was the staring point of our journey with Michio Jimbo in integrable models, the journey which finally led us to the exact results on the correlation functions of quantum spin chains in 1992.

  9. Comprehensive vibrational analysis of CO2 based on a polyad-preserving model*

    Science.gov (United States)

    Bermudez-Montaña, Marisol; Lemus, Renato; Pérez-Bernal, Francisco; Carvajal, Miguel

    2017-06-01

    We present a polyad-preserving algebraic approach to molecular structure and, as an application, we fit the model parameters to reproduce an extensive experimental data set of vibrational energies of carbon dioxide in its ground electronic state. The data set includes levels with vibrational angular momentum ℓ = 1, ...,6 and some recently obtained term values that have not been previously considered. The obtained results are close to experimental uncertainty and we compare the results obtained making use of the three most common polyad schemes that can be found in the literature for this molecular species.

  10. Solar drying of mangoes: preservation of an important source of vitamin A in French-speaking West Africa.

    Science.gov (United States)

    Rankins, Jenice; Sathe, Shridhar K; Spicer, Maria T

    2008-06-01

    Vitamin A deficiency, which is especially widespread among children younger than age 5 years, is a major barrier to reducing child mortality rates in French-speaking West Africa. A large amount of an indigenous plant source of provitamin A carotenoids are lost to postharvest waste. For example, the postharvest loss of mangoes in the region exceeds an annual total of 100,000 metric tons. In our study, 3.75 metric tons of fresh mangoes were dried using a solar dryer to a final moisture content of 10% to 12%, yielding a total of 360 kg dried mango. The product analysis revealed 4,000+/-500 microg beta carotene/100 g and 3,680+/-150 microg beta carotene/100 g after 2 and 6 months of storage, respectively. Thus, one greenhouse solar dryer is capable of reducing postharvest mango waste by 3.75 tons providing up to 1.15 million retinol activity equivalents of dietary vitamin A. The use of this technology that requires solar energy and manpower has the potential of increasing dietary vitamin A supply by up to 27,000-fold, compared to the currently available vitamin A in the region. Moreover, mango is a fruit that is well-liked by the population in this geographic area increasing the likelihood of its ready acceptance. Reducing postharvest loss of mangoes by using greenhouse model solar dryers is a promising strategy to help combat vitamin A deficiency in French-speaking West Africa.

  11. The evaluation of aprotinin contained preservation solution with a new animal model

    Institute of Scientific and Technical Information of China (English)

    FU Qing-lin; ZHANG Xin-zhong; HAN Pei-li; SHI Rui-feng

    2008-01-01

    Objective To explore the protective effect of aprotinin contained LPD ( low potassium dextran) solution via an in situ rabbit lung preservation model. Methods Thirty New Zealand rabbits were divided randomly into 3 groups, 10 in each group. In group A (control group), the left lung hilus was clamped without solution perfusion; In group B ( LPD group) and group C ( aprotinin group), the lungs were perfused with LPD solution and aprotinin contained LPD, respectively. The lungs in all groups were stored at 10 centigrade in a specially made lung preservation container for 2 hours and then unclamped the lung hilus to rcperfuse the lung for 2 hours. Pulmonary venous blood samples were collected at pre-clamping of lung hilus,5 minutes and 120 minutes after reperfusion for analysis of blood gas. Biopsy of lung tissue was excised for morphological examination at pre-unclamping of lung hilas and 2 hours after reperfusion. Examination of bronchoalveolar lavage fluid was taken for the evaluation of inflammation status. Results Pulmonary venous partial pressure of oxygen ( PvPO2) in the 3 groups at 5 minutes and 120 minutes after reperfusion were significantly higher than those before clamping of lung hilus,respectively. PvPO2 in group A and group B at 120 minutes after reperfusion were significantly higher than those at 5 minutes after reperfusion. There was no significant difference of PvPO2 in group C between 5 minutes and 120 minutes after reperfusion. PvPO2 in group C at 5 minutes and 120 minutes after reperfusion were significantly higher than those in group A and group B. The morphological lesion was more severe in group A and B than that in group C. The PMN percentage in bronchoalveelar lavage fluid in group A and B was significantly higher than that in group C. Conclusions The protective effect of aprotinin is obvious for lung protection in animal model. Aprotinin contained lung preservation solution is superior to LPD for lung protection.

  12. Modeling urban housing market dynamics: can the socio-spatial segregation preserve some social diversity?

    CERN Document Server

    Gauvin, Laetitia; Nadal, Jean-Pierre

    2010-01-01

    This paper is concerned with issues related to social diversity in urban environments. We introduce a model of real estate transactions between agents which are heterogeneous in their willingness to pay. A key feature of the model is the assumption that agents preferences for a location depend both on an intrinsic attractiveness of the location, and on the social characteristics of its neighborhood. Focusing on the case of a monocentric city, the stationary state is analytically characterized and gives the distribution of income over space. The model is studied through numerical simulations as well. The analytical and numerical analysis reveal that, even if socio-spatial segregation occurs, some social diversity is preserved at most locations. Comparing with empirical data on transaction prices in Paris, the results are shown to nicely fit some stylized facts.

  13. On Multiscale Modeling: Preserving Energy Dissipation Across the Scales with Consistent Handshaking Methods

    Science.gov (United States)

    Pineda, Evan J.; Bednarcyk, Brett A.; Arnold, Steven M.; Waas, Anthony M.

    2013-01-01

    A mesh objective crack band model was implemented within the generalized method of cells micromechanics theory. This model was linked to a macroscale finite element model to predict post-peak strain softening in composite materials. Although a mesh objective theory was implemented at the microscale, it does not preclude pathological mesh dependence at the macroscale. To ensure mesh objectivity at both scales, the energy density and the energy release rate must be preserved identically across the two scales. This requires a consistent characteristic length or localization limiter. The effects of scaling (or not scaling) the dimensions of the microscale repeating unit cell (RUC), according to the macroscale element size, in a multiscale analysis was investigated using two examples. Additionally, the ramifications of the macroscale element shape, compared to the RUC, was studied.

  14. A Unified Detail-Preserving Liquid Simulation by Two-Phase Lattice Boltzmann Modeling.

    Science.gov (United States)

    Guo, Yulong; Liu, Xiaopei; Xu, Xuemiao

    2016-02-19

    Traditional methods in graphics to simulate liquid-air dynamics under different scenarios usually employ separate approaches with sophisticated interface tracking/reconstruction techniques. In this paper, we propose a novel unified approach which is easy and effective to produce a variety of liquid-air interface phenomena. These phenomena, such as complex surface splashes, bubble interactions, as well as surface tension effects, can co-exist in one single simulation, and are created within the same computational framework. Such a framework is unique in that it is free from any complicated interface tracking/reconstruction procedures. Our approach is developed from the two-phase lattice Boltzmann method with the mean field model, which provides a unified framework for interface dynamics but is numerically unstable under turbulent conditions. Considering the drawbacks of the existing approaches, we propose techniques to suppress oscillation for significant stability enhancement, as well as derive a new subgrid-scale model to further improve stability, faithfully preserving liquid-air interface details without excessive diffusion by taking into account the density variation. The whole framework is highly parallel, enabling very efficient implementation. Comparisons to the related approaches show superiority on stable simulation with detail preservation and multiphase phenomena simultaneously involved. A set of animation results demonstrate the effectiveness of our method.

  15. Multiple temperature model for the information preservation method and its application to nonequilibrium gas flows

    Science.gov (United States)

    Zhang, Jun; Fan, Jing; Jiang, Jianzheng

    2011-08-01

    The information preservation (IP) method has been successfully applied to various nonequilibrium gas flows. Comparing with the direct simulation Monte Carlo (DSMC) method, the IP method dramatically reduces the statistical scatter by preserving collective information of simulation molecules. In this paper, a multiple temperature model is proposed to extend the IP method to strongly translational nonequilibrium gas flows. The governing equations for the IP quantities have been derived from the Boltzmann equation based on an assumption that each simulation molecule represents a Gaussian distribution function with a second-order temperature tensor. According to the governing equations, the implementation of IP method is divided into three steps: molecular movement, molecular collision, and update step. With a reasonable multiple temperature collision model and the flux splitting method in the update step, the transport of IP quantities can be accurately modeled. We apply the IP method with the multiple temperature model to shear-driven Couette flow, external force-driven Poiseuille flow and thermal creep flow, respectively. In the former two cases, the separation of different temperature components is clearly observed in the transition regime, and the velocity, temperature and pressure distributions are also well captured. The thermal creep flow, resulting from the presence of temperature gradients along boundary walls, is properly simulated. All of the IP results compare well with the corresponding DSMC results, whereas the IP method uses much smaller sampling sizes than the DSMC method. This paper shows that the IP method with the multiple temperature model is an accurate and efficient tool to simulate strongly translational nonequilibrium gas flows.

  16. 三维模型近刚性保体变形%3D Model Quasi-rigid Deformation with Volume Preservation

    Institute of Scientific and Technical Information of China (English)

    刘炯宙; 李基拓; 陆国栋

    2013-01-01

    为保持三维模型表面细节和模型体积,提高模型变形的真实感效果,提出一种基于能量最小化的近刚性保体变形方法.首先对模型进行Laplacian变形,在此基础上,通过极分解求解曲面局部区域三角形的旋转变形,构建模型刚性变形能;然后通过模型体积积分离散化将模型体积变形约束转化为模型曲面变形约束,构建体积变形能;再通过衡量约束点的位置变形误差构建约束变形能.在最小二乘意义下最小化上述加权变形能,获得模型变形结果.实例结果表明,文中方法能够在线性的算法效率下获得近刚性保体变形效果,为模型的真实感变形提供了一条有效的途径.%Surface detail preservation and model volume preservation are two important aspects for 3D model realistic deformation. A large number of methods for preserving both of the above two aspects have been developed in the past few years. However neither sole detail preserved method nor sole volume preserved method can well preserve them. In this paper, a 3D quasi-rigid deformation integrated with volume preservation approach is proposed. Model deformation is achieved by iteratively minimizing a combined deformation energy: the surface rigidity energy measures the deviation degree of the local surface deformation from its ideal rigid deformation and is computed by polar decomposing the Laplacian surface deformation result; the volume deformation energy measures the volume changing during deformation and is expressed through discretizing the model surface volumetric integration; the constraint energy measures how well the customer's interactive constraints being met. Experimental results show that our approach can obtain quasi-rigid and volume-preserved model deformation results within linear algorithm complexity.

  17. Geostrophic balance preserving interpolation in mesh adaptive shallow-water ocean modelling

    CERN Document Server

    Maddison, James R; Farrell, Patrick E

    2010-01-01

    The accurate representation of geostrophic balance is an essential requirement for numerical modelling of geophysical flows. Significant effort is often put into the selection of accurate or optimal balance representation by the discretisation of the fundamental equations. The issue of accurate balance representation is particularly challenging when applying dynamic mesh adaptivity, where there is potential for additional imbalance injection when interpolating to new, optimised meshes. In the context of shallow-water modelling, we present a new method for preservation of geostrophic balance when applying dynamic mesh adaptivity. This approach is based upon interpolation of the Helmholtz decomposition of the Coriolis acceleration. We apply this in combination with a discretisation for which states in geostrophic balance are exactly steady solutions of the linearised equations on an f-plane; this method guarantees that a balanced and steady flow on a donor mesh remains balanced and steady after interpolation on...

  18. Symmetry-preserving contact interaction model for heavy-light mesons

    CERN Document Server

    Serna, F E; Krein, G

    2016-01-01

    We use a symmetry-preserving regularization method of ultraviolet divergences in a vector-vector contact interac- tion model for low-energy QCD. The contact interaction is a representation of nonperturbative kernels used Dyson-Schwinger and Bethe-Salpeter equations. The regularization method is based on a subtraction scheme that avoids standard steps in the evaluation of divergent integrals that invariably lead to symmetry violation. Aiming at the study of heavy-light mesons, we have implemented the method to the pseudoscalar pion and Kaon mesons. We have solved the Dyson-Schwinger equation for the u, d and s quark propagators, and obtained the bound-state Bethe-Salpeter amplitudes in a way that the Ward-Green-Takahashi identities reflecting global symmetries of the model are satisfied for arbitrary routing of the momenta running in loop integrals.

  19. Symmetry-preserving contact interaction model for heavy-light mesons

    Energy Technology Data Exchange (ETDEWEB)

    Serna, F. E.; Brito, M. A.; Krein, G. [Instituto de Física Teórica, Universidade Estadual Paulista (Brazil); Rua Dr. Bento Teobaldo Ferraz, 271 - Bloco II, 01140-070 São Paulo, SP (Brazil)

    2016-01-22

    We use a symmetry-preserving regularization method of ultraviolet divergences in a vector-vector contact interaction model for low-energy QCD. The contact interaction is a representation of nonperturbative kernels used Dyson-Schwinger and Bethe-Salpeter equations. The regularization method is based on a subtraction scheme that avoids standard steps in the evaluation of divergent integrals that invariably lead to symmetry violation. Aiming at the study of heavy-light mesons, we have implemented the method to the pseudoscalar π and K mesons. We have solved the Dyson-Schwinger equation for the u, d and s quark propagators, and obtained the bound-state Bethe-Salpeter amplitudes in a way that the Ward-Green-Takahashi identities reflecting global symmetries of the model are satisfied for arbitrary routing of the momenta running in loop integrals.

  20. Biodiversity in models of cyclic dominance is preserved by heterogeneity in site-specific invasion rates

    CERN Document Server

    Szolnoki, Attila

    2016-01-01

    Global, population-wide oscillations in models of cyclic dominance may result in the collapse of biodiversity due to the accidental extinction of one species in the loop. Previous research has shown that such oscillations can emerge if the interaction network has small-world properties, and more generally, because of long-range interactions among individuals or because of mobility. But although these features are all common in nature, global oscillations are rarely observed in actual biological systems. This begets the question what is the missing ingredient that would prevent local oscillations to synchronize across the population to form global oscillations. Here we show that, although heterogeneous species-specific invasion rates fail to have a noticeable impact on species coexistence, randomness in site-specific invasion rates successfully hinders the emergence of global oscillations and thus preserves biodiversity. Our model takes into account that the environment is often not uniform but rather spatiall...

  1. Frequency-Preserved Acoustic Diode Model with High Forward-Power-Transmission Rate

    Science.gov (United States)

    Liu, Chang; Du, Zongliang; Sun, Zhi; Gao, Huajian; Guo, Xu

    2015-06-01

    The acoustic diode (AD) can provide brighter and clearer ultrasound images by eliminating acoustic disturbances caused by sound waves traveling in two directions at the same time and interfering with each other. Such an AD could give designers new flexibility in making ultrasonic sources like those used in medical imaging or nondestructive testing. However, current AD designs, based on nonlinear effects, only partially fill this role by converting sound to a new frequency and blocking any backward flow of the original frequency. In this work, an AD model that preserves the frequencies of acoustic waves and has a relatively high forward-power-transmission rate is proposed. Theoretical analysis indicates that the proposed AD has forward, reverse, and breakdown characteristics very similar to electrical diodes. The significant rectifying effect of the proposed AD is verified numerically through a one-dimensional example. Possible schemes for experimental realization of this model as well as more complex and efficient AD designs are also discussed.

  2. Importance of predictor variables for models of chemical function

    Data.gov (United States)

    U.S. Environmental Protection Agency — Importance of random forest predictors for all classification models of chemical function. This dataset is associated with the following publication: Isaacs , K., M....

  3. Feature, design intention and constraint preservation for direct modeling of 3D freeform surfaces

    Science.gov (United States)

    Fu, Luoting; Kara, Levent Burak; Shimada, Kenji

    2012-06-01

    Direct modeling has recently emerged as a suitable approach for 3D free-form shape modeling in industrial design. It has several advantages over the conventional, parametric modeling techniques, including natural user interactions, as well as the underlying, automatic feature-preserving shape deformation algorithms. However, current direct modeling packages still lack several capabilities critical for product design, such as managing aesthetic design intentions, and enforcing dimensional, geometric constraints. In this paper, we describe a novel 3D surface editing system capable of jointly accommodating aesthetic design intentions expressed in the form of surface painting and color-coded annotations, as well as engineering constraints expressed as dimensions. The proposed system is built upon differential coordinates and constrained least squares, and is intended for conceptual design that involves frequent shape tuning and explorations. We also provide an extensive review of the state-of-the-art direct modeling approaches for 3D mesh-based, freeform surfaces, with an emphasis on the two broad categories of shape deformation algorithms developed in the relevant field of geometric modeling. [Figure not available: see fulltext.

  4. Acute inhibition of myostatin-family proteins preserves skeletal muscle in mouse models of cancer cachexia

    Energy Technology Data Exchange (ETDEWEB)

    Benny Klimek, Margaret E.; Aydogdu, Tufan [Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL (United States); Link, Majik J.; Pons, Marianne [Molecular Oncology Program, Division of Surgical Oncology, DeWitt Daughtry Family Department of Surgery, University of Miami Miller School of Medicine, Miami, FL (United States); Koniaris, Leonidas G. [Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL (United States); Molecular Oncology Program, Division of Surgical Oncology, DeWitt Daughtry Family Department of Surgery, University of Miami Miller School of Medicine, Miami, FL (United States); Molecular Oncology and Experimental Therapeutics Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL (United States); Zimmers, Teresa A., E-mail: tzimmers@med.miami.edu [Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL (United States); Molecular Oncology Program, Division of Surgical Oncology, DeWitt Daughtry Family Department of Surgery, University of Miami Miller School of Medicine, Miami, FL (United States); Molecular Oncology and Experimental Therapeutics Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL (United States)

    2010-01-15

    Cachexia, progressive loss of fat and muscle mass despite adequate nutrition, is a devastating complication of cancer associated with poor quality of life and increased mortality. Myostatin is a potent tonic muscle growth inhibitor. We tested how myostatin inhibition might influence cancer cachexia using genetic and pharmacological approaches. First, hypermuscular myostatin null mice were injected with Lewis lung carcinoma or B16F10 melanoma cells. Myostatin null mice were more sensitive to tumor-induced cachexia, losing more absolute mass and proportionately more muscle mass than wild-type mice. Because myostatin null mice lack expression from development, however, we also sought to manipulate myostatin acutely. The histone deacetylase inhibitor Trichostatin A has been shown to increase muscle mass in normal and dystrophic mice by inducing the myostatin inhibitor, follistatin. Although Trichostatin A administration induced muscle growth in normal mice, it failed to preserve muscle in colon-26 cancer cachexia. Finally we sought to inhibit myostatin and related ligands by administration of the Activin receptor extracellular domain/Fc fusion protein, ACVR2B-Fc. Systemic administration of ACVR2B-Fc potently inhibited muscle wasting and protected adipose stores in both colon-26 and Lewis lung carcinoma cachexia, without affecting tumor growth. Enhanced cachexia in myostatin knockouts indicates that host-derived myostatin is not the sole mediator of muscle wasting in cancer. More importantly, skeletal muscle preservation with ACVR2B-Fc establishes that targeting myostatin-family ligands using ACVR2B-Fc or related molecules is an important and potent therapeutic avenue in cancer cachexia.

  5. Development and validation of an extensive growth and growth boundary model for Listeria monocytogenes in lightly preserved and ready-to-eat shrimp

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Dalgaard, Paw

    2009-01-01

    An existing cardinal parameter growth and growth boundary model for Listeria monocytogenes (O. Mejlholm and P. Dalgaard, J. Food Prot. 70:70-84 and 2485-2497, 2007) was expanded with terms for the effects of acetic, benzoic, citric, and sorbic acids to include a total of 12 environmental parameters...... degree of complexity. The high number of environmental parameters, inclu! ding six organic acids (acetic acid, benzoic acid, citric acid, diacetate, lactic acid, and sorbic acid), allows the new model to predict the effect of substituting one set of preserving parameters for another. The new model also...... allowed the distance between the growth boundary and specific product characteristics to be quantified by a psi value. This can be of practical importance in the development or reformulation of seafood with preserving parameters that prevent growth of L. monocytogenes and take variability in product...

  6. Employee important-satisfaction model for automotive industry

    Science.gov (United States)

    Aziz, Nazrina; Mahat, Nor Idayu; Omar, Zurni

    2014-12-01

    There are many available strategies to measure employee satisfaction. Among the common strategies are employee responses to supervisors during routine meetings or periodic assessments of performance, number of complaints and feedback from employees. Although the management of the company may expect what its employees are most satisfied with, they may not know what is important to their employees' satisfaction. The "satisfaction attributes" and the "importance attributes" are related components that worth to be taken into account. Besides, the management needs to identify what their employees' priorities are, otherwise the management could be wasting their limited energy and resources tackling wrong attributes. In this study the Important-Satisfaction model is proposed. The model is based on the importance and satisfaction score of the attributes where the score for each attribute is placed in the model. It assists the management in identifying attributes that require improvement and provide an excellent measuring instrument for assessing priorities for attribute improvement.

  7. The National Digital Information Infrastructure Preservation Program; Metadata Principles and Practicalities; Challenges for Service Providers when Importing Metadata in Digital Libraries; Integrated and Aggregated Reference Services.

    Science.gov (United States)

    Friedlander, Amy; Duval, Erik; Hodgins, Wayne; Sutton, Stuart; Weibel, Stuart L.; McClelland, Marilyn; McArthur, David; Giersch, Sarah; Geisler, Gary; Hodgkin, Adam

    2002-01-01

    Includes 6 articles that discuss the National Digital Information Infrastructure Preservation Program at the Library of Congress; metadata in digital libraries; integrated reference services on the Web. (LRW)

  8. The National Digital Information Infrastructure Preservation Program; Metadata Principles and Practicalities; Challenges for Service Providers when Importing Metadata in Digital Libraries; Integrated and Aggregated Reference Services.

    Science.gov (United States)

    Friedlander, Amy; Duval, Erik; Hodgins, Wayne; Sutton, Stuart; Weibel, Stuart L.; McClelland, Marilyn; McArthur, David; Giersch, Sarah; Geisler, Gary; Hodgkin, Adam

    2002-01-01

    Includes 6 articles that discuss the National Digital Information Infrastructure Preservation Program at the Library of Congress; metadata in digital libraries; integrated reference services on the Web. (LRW)

  9. Jump-Preserving Varying-Coefficient Models for Nonlinear Time Series

    NARCIS (Netherlands)

    Cizek, Pavel; Koo, Chao

    2017-01-01

    An important and widely used class of semiparametric models is formed by the varyingcoefficient models. Although the varying coefficients are traditionally assumed to be smooth functions, the varying-coefficient model is considered here with the coefficient functions containing a finite set of disco

  10. Model-Free importance indicators for dependent input

    Energy Technology Data Exchange (ETDEWEB)

    Saltelli, A.; Ratto, M.; Tarantola, S

    2001-07-01

    A number of methods are available to asses uncertainty importance in the predictions of a simulation model for orthogonal sets of uncertain input factors. However, in many practical cases input factors are correlated. Even for these cases it is still possible to compute the correlation ratio and the partial (or incremental) importance measure, two popular sensitivity measures proposed in the recent literature on the subject. Unfortunately, the existing indicators of importance have limitations in terms of their use in sensitivity analysis of model output. Correlation ratios are indeed effective for priority setting (i.e. to find out what input factor needs better determination) but not, for instance, for the identification of the subset of the most important input factors, or for model simplification. In such cases other types of indicators are required that can cope with the simultaneous occurrence of correlation and interaction (a property of the model) among the input factors. In (1) the limitations of current measures of importance were discussed and a general approach was identified to quantify uncertainty importance for correlated inputs in terms of different betting contexts. This work was later submitted to the Journal of the American Statistical Association. However, the computational cost of such approach is still high, as it happens when dealing with correlated input factors. In this paper we explore how suitable designs could reduce the numerical load of the analysis. (Author) 11 refs.

  11. Comparison of Two Stochastic Daily Rainfall Models and their Ability to Preserve Multi-year Rainfall Variability

    Science.gov (United States)

    Kamal Chowdhury, AFM; Lockart, Natalie; Willgoose, Garry; Kuczera, George; Kiem, Anthony; Parana Manage, Nadeeka

    2016-04-01

    Stochastic simulation of rainfall is often required in the simulation of streamflow and reservoir levels for water security assessment. As reservoir water levels generally vary on monthly to multi-year timescales, it is important that these rainfall series accurately simulate the multi-year variability. However, the underestimation of multi-year variability is a well-known issue in daily rainfall simulation. Focusing on this issue, we developed a hierarchical Markov Chain (MC) model in a traditional two-part MC-Gamma Distribution modelling structure, but with a new parameterization technique. We used two parameters of first-order MC process (transition probabilities of wet-to-wet and dry-to-dry days) to simulate the wet and dry days, and two parameters of Gamma distribution (mean and standard deviation of wet day rainfall) to simulate wet day rainfall depths. We found that use of deterministic Gamma parameter values results in underestimation of multi-year variability of rainfall depths. Therefore, we calculated the Gamma parameters for each month of each year from the observed data. Then, for each month, we fitted a multi-variate normal distribution to the calculated Gamma parameter values. In the model, we stochastically sampled these two Gamma parameters from the multi-variate normal distribution for each month of each year and used them to generate rainfall depth in wet days using the Gamma distribution. In another study, Mehrotra and Sharma (2007) proposed a semi-parametric Markov model. They also used a first-order MC process for rainfall occurrence simulation. But, the MC parameters were modified by using an additional factor to incorporate the multi-year variability. Generally, the additional factor is analytically derived from the rainfall over a pre-specified past periods (e.g. last 30, 180, or 360 days). They used a non-parametric kernel density process to simulate the wet day rainfall depths. In this study, we have compared the performance of our

  12. Finite Element Surface Registration Incorporating Curvature, Volume Preservation, and Statistical Model Information

    Directory of Open Access Journals (Sweden)

    Thomas Albrecht

    2013-01-01

    Full Text Available We present a novel method for nonrigid registration of 3D surfaces and images. The method can be used to register surfaces by means of their distance images, or to register medical images directly. It is formulated as a minimization problem of a sum of several terms representing the desired properties of a registration result: smoothness, volume preservation, matching of the surface, its curvature, and possible other feature images, as well as consistency with previous registration results of similar objects, represented by a statistical deformation model. While most of these concepts are already known, we present a coherent continuous formulation of these constraints, including the statistical deformation model. This continuous formulation renders the registration method independent of its discretization. The finite element discretization we present is, while independent of the registration functional, the second main contribution of this paper. The local discontinuous Galerkin method has not previously been used in image registration, and it provides an efficient and general framework to discretize each of the terms of our functional. Computational efficiency and modest memory consumption are achieved thanks to parallelization and locally adaptive mesh refinement. This allows for the first time the use of otherwise prohibitively large 3D statistical deformation models.

  13. Preservation Copying Endangered Historic Negative Collections

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad

    2008-01-01

    This article discusses preservation copying of unstable B&W nitrate and acetate still photographic negatives. It focuses on evaluating two different strategies for preserving the copies from a point of view of quality and cost-effectiveness. The evaluated strategies are preservation of the master...... by describing essential characteristics of negatives, which must be passed on to the copies, and the required metadata and technical imaging specifications. Next the paper discusses strategies for preservation and makes an analysis with the LIFE2 Costing Model. The paper concludes that the most beneficial...... and cost-effective preservation solution for large format negatives is to keep the preservation copies as digital files. However, it also acknowledges that it is important to revisit such strategies regularly to monitor changes in user expectations, technologies and costs....

  14. Modeling the Visual and Linguistic Importance of Objects

    Directory of Open Access Journals (Sweden)

    Moreno Ignazio Coco

    2012-05-01

    Full Text Available Previous work measuring the visual importance of objects has shown that only spatial information, such as object position and size, is predictive of importance, whilst low-level visual information, such as saliency, is not (Spain and Perona 2010, IJCV 91, 59–76. Objects are not important solely on the basis of their appearance. Rather, they are important because of their contextual information (eg, a pen in an office versus in a bathroom, which is needed in tasks requiring cognitive control (eg, visual search; Henderson 2007, PsySci 16 219–222. Given that most visual objects have a linguistic counterpart, their importance depends also on linguistic information, especially in tasks where language is actively involved—eg, naming. In an eye-tracking naming study, where participants are asked to name 5 objects in a scene, we investigated how visual saliency, contextual features, and linguistic information of the mentioned objects predicted their importance. We measured object importance based on the urn model of Spain and Perona (2010 and estimated the predictive role of visual and linguistic features using different regression frameworks: LARS (Efron et al 2004, Annals of Statistics 32 407–499 and LME (Baayen et al 2008, JML 59, 390–412. Our results confirmed the role of spatial information in predicting object importance, and in addition, we found effects of saliency. Crucially to our hypothesis, we demonstrated that the lexical frequency of objects and their contextual fit in the scene significantly contributed to object importance.

  15. The Importance of Statistical Modeling in Data Analysis and Inference

    Science.gov (United States)

    Rollins, Derrick, Sr.

    2017-01-01

    Statistical inference simply means to draw a conclusion based on information that comes from data. Error bars are the most commonly used tool for data analysis and inference in chemical engineering data studies. This work demonstrates, using common types of data collection studies, the importance of specifying the statistical model for sound…

  16. Biodiversity in models of cyclic dominance is preserved by heterogeneity in site-specific invasion rates

    Science.gov (United States)

    Szolnoki, Attila; Perc, Matjaž

    2016-12-01

    Global, population-wide oscillations in models of cyclic dominance may result in the collapse of biodiversity due to the accidental extinction of one species in the loop. Previous research has shown that such oscillations can emerge if the interaction network has small-world properties, and more generally, because of long-range interactions among individuals or because of mobility. But although these features are all common in nature, global oscillations are rarely observed in actual biological systems. This begets the question what is the missing ingredient that would prevent local oscillations to synchronize across the population to form global oscillations. Here we show that, although heterogeneous species-specific invasion rates fail to have a noticeable impact on species coexistence, randomness in site-specific invasion rates successfully hinders the emergence of global oscillations and thus preserves biodiversity. Our model takes into account that the environment is often not uniform but rather spatially heterogeneous, which may influence the success of microscopic dynamics locally. This prevents the synchronization of locally emerging oscillations, and ultimately results in a phenomenon where one type of randomness is used to mitigate the adverse effects of other types of randomness in the system.

  17. [Skin and tissue bank: Operational model for the recovery and preservation of tissues and skin allografts].

    Science.gov (United States)

    Martínez-Flores, Francisco; Sandoval-Zamora, Hugo; Machuca-Rodriguez, Catalina; Barrera-López, Araceli; García-Cavazos, Ricardo; Madinaveitia-Villanueva, Juan Antonio

    2016-01-01

    Tissue storage is a medical process that is in the regulation and homogenisation phase in the scientific world. The international standards require the need to ensure safety and efficacy of human allografts such as skin and other tissues. The activities of skin and tissues banks currently involve their recovery, processing, storage and distribution, which are positively correlated with technological and scientific advances present in current biomedical sciences. A description is presented of the operational model of Skin and Tissue Bank at INR as successful case for procurement, recovery and preservation of skin and tissues for therapeutic uses, with high safety and biological quality. The essential and standard guidelines are presented as keystones for a tissue recovery program based on scientific evidence, and within an ethical and legal framework, as well as to propose a model for complete overview of the donation of tissues and organ programs in Mexico. Finally, it concludes with essential proposals for improving the efficacy of transplantation of organs and tissue programs. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

  18. Homology modeling: an important tool for the drug discovery.

    Science.gov (United States)

    França, Tanos Celmar Costa

    2015-01-01

    In the last decades, homology modeling has become a popular tool to access theoretical three-dimensional (3D) structures of molecular targets. So far several 3D models of proteins have been built by this technique and used in a great diversity of structural biology studies. But are those models consistent enough with experimental structures to make this technique an effective and reliable tool for drug discovery? Here we present, briefly, the fundamentals and current state-of-the-art of the homology modeling techniques used to build 3D structures of molecular targets, which experimental structures are not available in databases, and list some of the more important works, using this technique, available in literature today. In many cases those studies have afforded successful models for the drug design of more selective agonists/antagonists to the molecular targets in focus and guided promising experimental works, proving that, when the appropriate templates are available, useful models can be built using some of the several software available today for this purpose. Limitations of the experimental techniques used to solve 3D structures allied to constant improvements in the homology modeling software will maintain the need for theoretical models, establishing the homology modeling as a fundamental tool for the drug discovery.

  19. Area-preserving maps models of gyroaveraged E×B chaotic transport

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, J. D. da, E-mail: jfonseca@if.usp.br; Caldas, I. L., E-mail: ibere@if.usp.br [Institute of Physics, University of São Paulo, São Paulo, SP 5315-970 (Brazil); Castillo-Negrete, D. del, E-mail: delcastillod@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)

    2014-09-15

    Discrete maps have been extensively used to model 2-dimensional chaotic transport in plasmas and fluids. Here we focus on area-preserving maps describing finite Larmor radius (FLR) effects on E × B chaotic transport in magnetized plasmas with zonal flows perturbed by electrostatic drift waves. FLR effects are included by gyro-averaging the Hamiltonians of the maps which, depending on the zonal flow profile, can have monotonic or non-monotonic frequencies. In the limit of zero Larmor radius, the monotonic frequency map reduces to the standard Chirikov-Taylor map, and in the case of non-monotonic frequency, the map reduces to the standard nontwist map. We show that in both cases FLR leads to chaos suppression, changes in the stability of fixed points, and robustness of transport barriers. FLR effects are also responsible for changes in the phase space topology and zonal flow bifurcations. Dynamical systems methods based on the counting of recurrences times are used to quantify the dependence on the Larmor radius of the threshold for the destruction of transport barriers.

  20. Reduced-order Structure-preserving Model for Parallel-connected Three-phase Grid-tied Inverters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-31

    Given that next-generation infrastructures will contain large numbers of grid-connected inverters and these interfaces will be satisfying a growing fraction of system load, it is imperative to analyze the impacts of power electronics on such systems. However, since each inverter model has a relatively large number of dynamic states, it would be impractical to execute complex system models where the full dynamics of each inverter are retained. To address this challenge, we derive a reduced-order structure-preserving model for parallel-connected grid-tied three-phase inverters. Here, each inverter in the system is assumed to have a full-bridge topology, LCL filter at the point of common coupling, and the control architecture for each inverter includes a current controller, a power controller, and a phase-locked loop for grid synchronization. We outline a structure-preserving reduced-order inverter model for the setting where the parallel inverters are each designed such that the filter components and controller gains scale linearly with the power rating. By structure preserving, we mean that the reduced-order three-phase inverter model is also composed of an LCL filter, a power controller, current controller, and PLL. That is, we show that the system of parallel inverters can be modeled exactly as one aggregated inverter unit and this equivalent model has the same number of dynamical states as an individual inverter in the paralleled system. Numerical simulations validate the reduced-order models.

  1. [Two woman medical doctors of the Meiji era who came from the "Preservative District of Johnai Suwakohji Important Traditional Buildings Group", Kanegasaki Town, Iwate Prefecture].

    Science.gov (United States)

    Fukushima, Masakazu

    2010-09-01

    There is a historical group of samurai buildings called the "Preservative District of Johnai Suwakohji Important Traditional Buildings Group" in Kanegasaki Town, Iwate Prefecture. Two woman medical doctors (Misaho Aizawa and Mie Shiga, came from this district at the end of the Meiji Era (1910-1911). Misaho Aizawa was born in a minister's family in 1885 and studied at the Women's School of Dohshisha. After graduation she studied abroad at the Women's Medical College of Philadelphia and graduated from the college in 1910. Immediately after graduation she came back to Japan and got a medical license in Japan. She married a minister and was employed by the Red Cross Clinic in Fukuoka Prefecture. Mie Shiga was born in a samurai-family in 1880 and worked her way through various medical schools in Tokyo. After three failures to pass the national medical examination she received a medical license in 1911. In 1913 she opened her clinic of internal medicine & pediatrics in Utsunomiya. She made an effort to diagnose correctly and won patients' confidence. These two women had neither communication nor common points due to the differences of their family environment and their age. However, they were brought up by fathers who were enthusiastic for education and they made an effort to become woman doctors. Although women's social situation and the female compulsory education rate were low, and women's medical education was poor in the Meiji Era, Misaho Aizawa was able to enter the medical route under the influence of Christianity, and Mie Shiga through the assistance of her family and her samurai spirit.

  2. Landscape as a model: the importance of geometry.

    Science.gov (United States)

    Holland, E Penelope; Aegerter, James N; Dytham, Calvin; Smith, Graham C

    2007-10-01

    In all models, but especially in those used to predict uncertain processes (e.g., climate change and nonnative species establishment), it is important to identify and remove any sources of bias that may confound results. This is critical in models designed to help support decisionmaking. The geometry used to represent virtual landscapes in spatially explicit models is a potential source of bias. The majority of spatial models use regular square geometry, although regular hexagonal landscapes have also been used. However, there are other ways in which space can be represented in spatially explicit models. For the first time, we explicitly compare the range of alternative geometries available to the modeller, and present a mechanism by which uncertainty in the representation of landscapes can be incorporated. We test how geometry can affect cell-to-cell movement across homogeneous virtual landscapes and compare regular geometries with a suite of irregular mosaics. We show that regular geometries have the potential to systematically bias the direction and distance of movement, whereas even individual instances of landscapes with irregular geometry do not. We also examine how geometry can affect the gross representation of real-world landscapes, and again show that individual instances of regular geometries will always create qualitative and quantitative errors. These can be reduced by the use of multiple randomized instances, though this still creates scale-dependent biases. In contrast, virtual landscapes formed using irregular geometries can represent complex real-world landscapes without error. We found that the potential for bias caused by regular geometries can be effectively eliminated by subdividing virtual landscapes using irregular geometry. The use of irregular geometry appears to offer spatial modellers other potential advantages, which are as yet underdeveloped. We recommend their use in all spatially explicit models, but especially for predictive models

  3. Memory-preserving equilibration after a quantum quench in a one-dimensional critical model

    Science.gov (United States)

    Sotiriadis, Spyros

    2016-09-01

    One of the fundamental principles of statistical physics is that only partial information about a system's state is required for its macroscopic description. This is not only true for thermal ensembles, but also for the unconventional ensemble, known as generalized Gibbs ensemble (GGE), that is expected to describe the relaxation of integrable systems after a quantum quench. By analytically studying the quench dynamics in a prototypical one-dimensional critical model, the massless free bosonic field theory, we find evidence of a novel type of equilibration characterized by the preservation of an enormous amount of memory of the initial state that is accessible by local measurements. In particular, we show that the equilibration retains memory of non-Gaussian initial correlations, in contrast to the case of massive free evolution which erases all such memory. The GGE in its standard form, being a Gaussian ensemble, fails to predict correctly the equilibrium values of local observables, unless the initial state is Gaussian itself. Our findings show that the equilibration of a broad class of quenches whose evolution is described by Luttinger liquid theory with an initial state that is non-Gaussian in terms of the bosonic field, is not correctly captured by the corresponding bosonic GGE, raising doubts about the validity of the latter in general one-dimensional gapless integrable systems such as the Lieb-Liniger model. We also propose that the same experiment by which the GGE was recently observed [Langen et al., Science 348, 207 (2015), 10.1126/science.1257026] can also be used to observe its failure, simply by starting from a non-Gaussian initial state.

  4. The importance of understanding: Model space moderates goal specificity effects.

    Science.gov (United States)

    Kistner, Saskia; Burns, Bruce D; Vollmeyer, Regina; Kortenkamp, Ulrich

    2016-01-01

    The three-space theory of problem solving predicts that the quality of a learner's model and the goal specificity of a task interact on knowledge acquisition. In Experiment 1 participants used a computer simulation of a lever system to learn about torques. They either had to test hypotheses (nonspecific goal), or to produce given values for variables (specific goal). In the good- but not in the poor-model condition they saw torque depicted as an area. Results revealed the predicted interaction. A nonspecific goal only resulted in better learning when a good model of torques was provided. In Experiment 2 participants learned to manipulate the inputs of a system to control its outputs. A nonspecific goal to explore the system helped performance when compared to a specific goal to reach certain values when participants were given a good model, but not when given a poor model that suggested the wrong hypothesis space. Our findings support the three-space theory. They emphasize the importance of understanding for problem solving and stress the need to study underlying processes.

  5. Topology preserving non-rigid image registration using time-varying elasticity model for MRI brain volumes.

    Science.gov (United States)

    Ahmad, Sahar; Khan, Muhammad Faisal

    2015-12-01

    In this paper, we present a new non-rigid image registration method that imposes a topology preservation constraint on the deformation. We propose to incorporate the time varying elasticity model into the deformable image matching procedure and constrain the Jacobian determinant of the transformation over the entire image domain. The motion of elastic bodies is governed by a hyperbolic partial differential equation, generally termed as elastodynamics wave equation, which we propose to use as a deformation model. We carried out clinical image registration experiments on 3D magnetic resonance brain scans from IBSR database. The results of the proposed registration approach in terms of Kappa index and relative overlap computed over the subcortical structures were compared against the existing topology preserving non-rigid image registration methods and non topology preserving variant of our proposed registration scheme. The Jacobian determinant maps obtained with our proposed registration method were qualitatively and quantitatively analyzed. The results demonstrated that the proposed scheme provides good registration accuracy with smooth transformations, thereby guaranteeing the preservation of topology.

  6. The importance of volume exclusion in modelling cellular migration.

    Science.gov (United States)

    Dyson, Louise; Baker, Ruth E

    2015-09-01

    The modelling of collective migration has traditionally been undertaken in a continuous framework, with little reference to the individual-level mechanisms that give rise to such a concerted movement. One factor whose importance is now coming to light is that the individuals themselves occupy space in the domain, thus obstructing others from moving past them (volume exclusion). In this work, we systematically derive continuous descriptions of cellular migration with volume exclusion for a wide range of individual-based mechanisms and in one, two and three dimensions. We also consider subpopulations of migrating individuals, which may have different characteristics, such as differing sizes and speeds of migration. We demonstrate that volume exclusion is of particular importance when biased movement is included, and thus conclude that volume exclusion may have its greatest effect when considering directed migratory mechanisms such as chemotaxis.

  7. Modeling The Economics Of PACS: What Is Important?

    Science.gov (United States)

    Saarinen, Allan O.; Haynor, David R.; Loop, John W.; Johnson, Linda; Russell, John; Mitchell, Kate; Nemerever, Marilyn

    1989-05-01

    Picture Archive and Communications Systems (PACS) represent a significant long term capital investment for radiology departments and hospitals. Many radiology departments want to acquire this new imaging technology, but they are still concerned about the cost of these systems. While a few studies have tried to quantify the costs and benefits of PACS, these studies have been limited in scope. The University of Washington is evaluating a Digital Imaging Network System (DINS) and PACS for the U.S. Army Medical Research and Development Command. Part of this evaluation includes developing a comprehensive cost model of PACS for one of the military's large health care facilities (a 400 bed hospital). The paper summarizes the methodology and multi-layered spreadsheet model developed at the University to forecast the costs and potential cost savings this health care facility might accrue if a hospital wide PACS is installed and film is eliminated. It also discusses the many important assumptions made in the model. A sensitivity analysis of the model is also presented. The model indicates that keeping PACS maintenance costs down is particularly critical to the cost effectiveness of PACS. That is, the film cost savings attributed to PACS can be largely offset by PACS equipment maintenance cost. The cost effectiveness of PACS will also hinge upon whether a number of intangible benefits, such as referring physician and support staff productivity gains can be attributed to PACS. This model also suggests that the pay back period for a hospital wide PACS will vary significantly dependent upon the mix of tangible versus intangible cost savings incorporated into the modeling process.

  8. Pancreatic fistula may be an important complication following spleen-preserving radical gastrectomy with dissection of No.10 and No.11 lymph nodes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; ZHANG Zhong-tao; WANG Yu; WANG Kang-li

    2010-01-01

    @@ In recent years, spleen-preserving radical gastrectomy with dissection of No.10 and No.11 lymph nodes has been gradually accepted because of an improved understanding of immune function of the spleen in the perioperative period and for prognosis of gastric cancer.

  9. Importance of combined left atrial size and estimated pulmonary pressure for clinical outcome in patients presenting with heart failure with preserved ejection fraction

    DEFF Research Database (Denmark)

    Donal, Erwan; Lund, Lars H; Oger, Emmanuel

    2017-01-01

    Aims: Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome with various phenotypes and outcomes. The prognostic relevance of echocardiography and the E/e' ratio has previously been reported. We sought to study in addition, the value of estimated pulmonary pressure and left...

  10. Importance of resolution and model configuration when downscaling extreme precipitation

    Directory of Open Access Journals (Sweden)

    Adrian J. Champion

    2014-07-01

    Full Text Available Dynamical downscaling is frequently used to investigate the dynamical variables of extra-tropical cyclones, for example, precipitation, using very high-resolution models nested within coarser resolution models to understand the processes that lead to intense precipitation. It is also used in climate change studies, using long timeseries to investigate trends in precipitation, or to look at the small-scale dynamical processes for specific case studies. This study investigates some of the problems associated with dynamical downscaling and looks at the optimum configuration to obtain the distribution and intensity of a precipitation field to match observations. This study uses the Met Office Unified Model run in limited area mode with grid spacings of 12, 4 and 1.5 km, driven by boundary conditions provided by the ECMWF Operational Analysis to produce high-resolution simulations for the Summer of 2007 UK flooding events. The numerical weather prediction model is initiated at varying times before the peak precipitation is observed to test the importance of the initialisation and boundary conditions, and how long the simulation can be run for. The results are compared to raingauge data as verification and show that the model intensities are most similar to observations when the model is initialised 12 hours before the peak precipitation is observed. It was also shown that using non-gridded datasets makes verification more difficult, with the density of observations also affecting the intensities observed. It is concluded that the simulations are able to produce realistic precipitation intensities when driven by the coarser resolution data.

  11. Evaluation of Galleria mellonella larvae as an in vivo model for assessing the relative toxicity of food preservative agents.

    Science.gov (United States)

    Maguire, Ronan; Duggan, Orla; Kavanagh, Kevin

    2016-06-01

    Larvae of Galleria mellonella are widely used for evaluating the virulence of microbial pathogens and for measuring the efficacy of anti-microbial agents and produce results comparable to those that can be obtained using mammals. In this work, the suitability of using G. mellonella larvae to measure the relative toxicity of a variety of food preservatives was evaluated. The response of larvae to eight commonly used food preservatives (potassium nitrate, potassium nitrite, potassium sorbate, sodium benzoate, sodium nitrate, sodium chloride, sodium nitrite and sodium acetate) administered by feeding or by intra-haemocoel injection was measured. A significant correlation between the LD50 (R (2) = 0.8766, p = 0.0006) and LD80 (R (2) = 0.7629, p = 0.0046) values obtained due to oral or intra-haemocoel administration of compounds was established. The response of HEp-2 cells to the food preservatives was determined, and a significant correlation (R (2) = 0.7217, p = 0.0076) between the LD50 values of the compounds administered by feeding in larvae with the IC50 values of the compounds in HEp-2 cells was established. A strong correlation between the LD50 values of the eight food preservatives in G. mellonella larvae and rats (R (2) = 0.6506, p = 0.0156) was demonstrated. The results presented here indicate that G. mellonella larvae may be used as a model to evaluate the relative toxicity of food preservatives, and the results show a strong positive correlation to those obtained using established cell culture and mammalian models.

  12. Optimization of RNA preservation in granulation tissue in the expanded polytetrafluoroethylene (ePTFE) tube model

    DEFF Research Database (Denmark)

    Danielsen, Patricia L; Koudahl, V; Christensen, B;

    2009-01-01

    , removed after ten days and randomized to four RNA preservation groups. Storage in RNAlater at 4 degrees C and snap freezing in methanol/acetone yielded significantly better RNA quality than snap freezing with liquid nitrogen and storage in RNAlater at -80 degrees C. Snap freezing in liquid nitrogen failed...

  13. On the construction of discrete filters for symmetry-preserving regularization models

    NARCIS (Netherlands)

    Trias, F.X.; Verstappen, R.W.C.P.

    2011-01-01

    Since direct numerical simulations cannot be computed at high Reynolds numbers, a dynamically less complex formulation is sought. In the quest for such a formulation, we consider regularizations of the convective term that preserve the symmetry and conservation properties exactly. This requirement y

  14. Extensive cardinal parameter model to predict growth of pseudomonads in salt-reduced lightly preserved seafood

    DEFF Research Database (Denmark)

    Martinez Rios, Veronica; Dalgaard, Paw

    Interest in and demand for preserved seafood with reduced salt/sodium content is increasing. As a consequence of the reduced salt content potential growth of psychrotolerant pseudomonads to unacceptable high concentration where they cause product spoilage is an increasing challenge. Innovation...

  15. Gabor filter based optical image recognition using Fractional Power Polynomial model based common discriminant locality preserving projection with kernels

    Science.gov (United States)

    Li, Jun-Bao

    2012-09-01

    This paper presents Gabor filter based optical image recognition using Fractional Power Polynomial model based Common Kernel Discriminant Locality Preserving Projection. This method tends to solve the nonlinear classification problem endured by optical image recognition owing to the complex illumination condition in practical applications, such as face recognition. The first step is to apply Gabor filter to extract desirable textural features characterized by spatial frequency, spatial locality and orientation selectivity to cope with the variations in illumination. In the second step we propose Class-wise Locality Preserving Projection through creating the nearest neighbor graph guided by the class labels for the textural features reduction. Finally we present Common Kernel Discriminant Vector with Fractional Power Polynomial model to reduce the dimensions of the textural features for recognition. For the performance evaluation on optical image recognition, we test the proposed method on a challenging optical image recognition problem, face recognition.

  16. Information model for management and preservation of scientific digital memory of the Institute of Nuclear Engineering, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Sales, Luana Farias, E-mail: lsales@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Sayao, Luis Fernando, E-mail: isayao@cnen.gov.br [Centro de Informacoes Nucleares (CIN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    In the context of the data-oriented science (eScience), a considerable part of the results of research activities has been created in digital formats. This means that the memory of the scientific institutions involved in this new scientific paradigm may be at risk of being lost by rapid technological obsolescence, the known fragility of digital media and also by the fragmentation of information and knowledge scattered across multiples repositories. Thus, management of research data in a digital networked and distributed environment becomes an increasing challenge for the research world and the whole area of information: information science, librarianship, knowledge management, archival science and information technology; moreover, in the dynamic environment featuring eScience, there is a need for novel concepts of documents establishing a linkage between traditional documents - printed or digital - stored in repositories, with the data sets stored in data repositories. In this new research environment, an important issue is how to preserve these new complex documents so that they maintain their structure, meaning and authenticity and also its ability to be retrieved, accessed and reused through time and space. In this sense, this paper proposes an information model focused on the curation of scientific memory of the Institute of Nuclear Engineering of the Brazilian Commission of Nuclear Energy (CNEN/IEN). The model considers the traditional scientific documents (theses, articles, books, etc.) in digital formats and all other relevant data and information related to them, such as: scientific data, software, simulations, photos, videos, historical facts, news, etc., compounding an enhanced publication type oriented to the nuclear area. (author)

  17. Software preservation

    Directory of Open Access Journals (Sweden)

    Tadej Vodopivec

    2011-01-01

    Full Text Available Comtrade Ltd. covers a wide range of activities related to information and communication technologies; its deliverables include web applications, locally installed programs,system software, drivers, embedded software (used e.g. in medical devices, auto parts,communication switchboards. Also the extensive knowledge and practical experience about digital long-term preservation technologies have been acquired. This wide spectrum of activities puts us in the position to discuss the often overlooked aspect of the digital preservation - preservation of software programs. There are many resources dedicated to digital preservation of digital data, documents and multimedia records,but not so many about how to preserve the functionalities and features of computer programs. Exactly these functionalities - dynamic response to inputs - render the computer programs rich compared to documents or linear multimedia. The article opens the questions on the beginning of the way to the permanent digital preservation. The purpose is to find a way in the right direction, where all relevant aspects will be covered in proper balance. The following questions are asked: why at all to preserve computer programs permanently, who should do this and for whom, when we should think about permanent program preservation, what should be persevered (such as source code, screenshots, documentation, and social context of the program - e.g. media response to it ..., where and how? To illustrate the theoretic concepts given the idea of virtual national museum of electronic banking is also presented.

  18. Comparison of HTK- and UW-solution for liver preservation tested in an orthotopic liver transplantation model in the pig.

    Science.gov (United States)

    Steininger, R; Roth, E; Holzmüller, P; Reckendorfer, H; Grünberger, T; Sperlich, M; Burgmann, H; Moser, E; Feigl, W; Mühlbacher, F

    1992-01-01

    The aim of this experimental study was to compare the preservation potency of University of Wisconsin (UW) and HTK (Bretschneider) solutions in an orthotopic liver transplantation (OLT) model in pigs. Livers were harvested using an in situ perfusion technique, where organs were flushed with the solution being tested, stored on ice--cold storage (CS)--for 2 or 24 h and then transplanted. Parameters monitored were liver enzymes in serum, hepatic water content, high energy phosphates, nuclear magnetic resonance (NMR) relaxation time T2, light microscopy and bile production. CS for 24 h is an extreme in pig liver preservation and is not compatible with animal survival. Biopsies showed drastic morphological changes and grafts did not produce bile in either group. (Bile production 2 h CS: HTK, 5.6 +/- 1.8 ml/h; UW, 4.7 +/- 2.3 ml/h) Enzyme release after reperfusion (deltaSGOT, deltaLDH) was higher in long-term preservation. Hepatic tissue water content significantly decreased during CS in UW preserved livers. Edema alter reperfusion (deltaH2O: HTK 24 h = +5.6%, UW 24 h = +4.8%) and regeneration capacity after reperfusion (UW 2 h = 63%, HTK 2 h = 55%, UW 24 h = 30%, HTK 24 h = 30%) were not significantly different. However, we did not observe major differences in preservation potency between the solutions tested. Differences were correlated, rather, with length 9 time of CS, than with the solution used. Therefore, HTK solution seemed to be a low potassium containing alternative to UW solution.

  19. Examining an important urban transportation management tool: subarea modeling

    Directory of Open Access Journals (Sweden)

    Xueming CHEN

    2009-12-01

    Full Text Available At present, customized subarea models have been widely used in local transportation planning throughout the United States. The biggest strengths of a subarea model lie in its more detailed and accurate modeling outputs which better meet local planning requirements. In addition, a subarea model can substantially reduce database size and model running time. In spite of these advantages, subarea models remain quite weak in maintaining consistency with a regional model, modeling transit projects, smart growth measures, air quality conformity, and other areas. Both opportunities and threats exist for subarea modeling. In addition to examining subarea models, this paper introduces the decision-making process in choosing a proper subarea modeling approach (windowing versus focusing and software package. This study concludes that subarea modeling will become more popular in the future. More GIS applications, travel surveys, transit modeling, microsimulation software utilization, and other modeling improvements are expected to be incorporated into the subarea modeling process.

  20. [Effect of cold preservation and reperfusion injury on early-stage bile salt secretion after liver transplantation in rat model].

    Science.gov (United States)

    Chen, Geng; Ding, Min; Wang, Meng; Zhang, Yu-Jun; Li, Xiao-Wu; Wang, Shu-Guang; Dong, Jia-Hong

    2007-08-01

    To explore the effect of cold preservation and reperfusion injury (CPRI) on the bile salt spectrum in rat orthotopic liver transplantation (OLT) model. A special analysis method was established to investigate the bile salts in rat by reverse phase high performance liquid chromatography (RP-HPLC). Rats were randomly divided into 3 groups: group A (control group, n = 6), group B (group with 1 h graft preservation pre-OLT, n = 6) and group C (group with 12 h graft preservation pre-OLT, n = 6). The bile samples of 0 - 14 post-transplantation days were analyzed by RP-HPLC. Eleven kinds of bile salts were detected in rat bile. It showed that CPRI could influence the concentration of bile salts significantly in rat model after OLT, the concentration of hydrophobic bile salts (TCA and TCDCA) increased significantly in group B and C. However, the concentration of hydrophilic bile salts (TUDCA and THDCA) just increased in a short-time. The hydrophobicity index (HI) wasn't significantly changed during the first 4 post-transplant days. Thus the HI of bile salts elevated gradually from the 5th day and reached the peak at the 10th day after OLT. The increase of the proportion of hydrophobic bile salts may be one of the major factors leading to the increase of bile toxicity after OLT.

  1. 17-DMAG ameliorates polyglutamine-mediated motor neuron degeneration through well-preserved proteasome function in an SBMA model mouse.

    Science.gov (United States)

    Tokui, Keisuke; Adachi, Hiroaki; Waza, Masahiro; Katsuno, Masahisa; Minamiyama, Makoto; Doi, Hideki; Tanaka, Keiji; Hamazaki, Jun; Murata, Shigeo; Tanaka, Fumiaki; Sobue, Gen

    2009-03-01

    The ubiquitin-proteasome system (UPS) is the principal protein degradation system that tags and targets short-lived proteins, as well as damaged or misfolded proteins, for destruction. In spinal and bulbar muscular atrophy (SBMA), the androgen receptor (AR), an Hsp90 client protein, is such a misfolded protein that tends to aggregate in neurons. Hsp90 inhibitors promote the degradation of Hsp90 client proteins via the UPS. In a transgenic mouse model of SBMA, we examined whether a functioning UPS is preserved, if it was capable of degrading polyglutamine-expanded mutant AR, and what might be the therapeutic effects of 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG), an oral Hsp90 inhibitor. Ubiquitin-proteasomal function was well preserved in SBMA mice and was even increased during advanced stages when the mice developed severe phenotypes. Administration of 17-DMAG markedly ameliorated motor impairments in SBMA mice without detectable toxicity and reduced amounts of monomeric and nuclear-accumulated mutant AR. Mutant AR was preferentially degraded in the presence of 17-DMAG in both SBMA cell and mouse models when compared with wild-type AR. 17-DMAG also significantly induced Hsp70 and Hsp40. Thus, 17-DMAG would exert a therapeutic effect on SBMA via preserved proteasome function.

  2. Fertility Preservation for Female

    Institute of Scientific and Technical Information of China (English)

    Jack Huang; Seang Lin Tan; Ri-Cheng Chian

    2006-01-01

    Preservation of female fertility is an important issue today. However, there are few effective clinical options for preserving female fertility. Firstly, conventional in vitro fertilization (IVF) followed by embryo cryopreservation is an accepted procedure but is not applicable to all women. Embryo freezing is suitable only for women with a male partner and may not be acceptable to some patients due to moral and religious reasons. Ovarian tissue freezing is another option of female fertility preservation but is an invasive procedure and the efficacy of this technique remains to be determined.Oocyte cryopreservation is also method for fertility preservation. Egg freezing is minimally invasive and can avoid the ethical and moral concerns related to cryopreservation of embryos. However, conventional slow freezing/rapid thawing methods are associated with low survival of oocytes. Recent development in vitrification of oocytes appears promising. Therefore, vitrification of unfertilized eggs may be a novel method to preserve female fertility.

  3. DRP1 inhibition rescues retinal ganglion cells and their axons by preserving mitochondrial integrity in a mouse model of glaucoma.

    Science.gov (United States)

    Kim, K-Y; Perkins, G A; Shim, M S; Bushong, E; Alcasid, N; Ju, S; Ellisman, M H; Weinreb, R N; Ju, W-K

    2015-08-06

    Glaucoma is the leading cause of irreversible blindness and is characterized by slow and progressive degeneration of the optic nerve head axons and retinal ganglion cell (RGC), leading to loss of visual function. Although oxidative stress and/or alteration of mitochondrial (mt) dynamics induced by elevated intraocular pressure (IOP) are associated with this neurodegenerative disease, the mechanisms that regulate mt dysfunction-mediated glaucomatous neurodegeneration are poorly understood. Using a mouse model of glaucoma, DBA/2J (D2), which spontaneously develops elevated IOP, as well as an in vitro RGC culture system, we show here that oxidative stress, as evidenced by increasing superoxide dismutase 2 (SOD2) and mt transcription factor A (Tfam) protein expression, triggers mt fission and loss by increasing dynamin-related protein 1 (DRP1) in the retina of glaucomatous D2 mice as well as in cultured RGCs exposed to elevated hydrostatic pressure in vitro. DRP1 inhibition by overexpressing DRP1 K38A mutant blocks mt fission and triggers a subsequent reduction of oxidative stress, as evidenced by decreasing SOD2 and Tfam protein expression. DRP1 inhibition promotes RGC survival by increasing phosphorylation of Bad at serine 112 in the retina and preserves RGC axons by maintaining mt integrity in the glial lamina of glaucomatous D2 mice. These findings demonstrate an important vicious cycle involved in glaucomatous neurodegeneration that starts with elevated IOP producing oxidative stress; the oxidative stress then leads to mt fission and a specific form of mt dysfunction that generates further oxidative stress, thus perpetuating the cycle. Our findings suggest that DRP1 is a potential therapeutic target for ameliorating oxidative stress-mediated mt fission and dysfunction in RGC and its axons during glaucomatous neurodegeneration. Thus, DRP1 inhibition may provide a new therapeutic strategy for protecting both RGCs and their axons in glaucoma and other optic

  4. Modelling the growth/no growth boundary of Zygosaccharomyces bailii in acidic conditions: a contribution to the alternative method to preserve foods without using chemical preservatives.

    Science.gov (United States)

    Dang, T D T; Mertens, L; Vermeulen, A; Geeraerd, A H; Van Impe, J F; Debevere, J; Devlieghere, F

    2010-01-31

    The aim of the study was to develop mathematical models describing growth/no growth (G/NG) boundaries of the highly resistant food spoilage yeast-Zygosaccharomyces bailii-in different environmental conditions, taking acidified sauces as the target product. By applying these models, the stability of products with characteristics within the investigated pH, a(w) and acetic acid ranges can be evaluated. Besides, the well-defined no growth regions can be used in the development of guidelines regarding formulation of new shelf-stable foods without using chemical preservatives, which would facilitate the innovation of additive-free products. Experiments were performed at different temperatures and periods (22 degrees C for 45 and 60days, 30 degrees C for 45days) in 150 modified Sabouraud media characterized by high amount of sugars (glucose and fructose, 15% (w/v)), acetic acid (0.0-2.5% (v/v), 6 levels), pH (3.0-5.0, 5 levels) and a(w) (0.93-0.97, 5 levels). These time and temperature combinations were chosen as they are commonly applied for shelf-stable foods. The media were inoculated with ca. 4.5 log CFU/ml and yeast growth was monitored daily using optical density measurements. Every condition was examined in 20 replicates in order to yield accurate growth probabilities. Three separate ordinary logistic regression models were developed for different tested temperatures and incubation time. The total acetic acid concentration was considered as variable for all models. In general, when one intrinsic inhibitory factor became more stringent, the G/NG boundary shifted to less stressful conditions of the other two factors, resulting in enlarged no growth zones. Abrupt changes of growth probability often occurred around the transition zones (between growth and no growth regions), which indicates that minor variations in environmental conditions near the G/NG boundaries can cause a significant impact on the growth probability. When comparing growth after 45days between the

  5. Developing Terrestrial Trophic Models for Petroleum and Natural Gas Exploration and Production Sites: The Oklahoma Tallgrass Prairie Preserve Example

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, M; Coty, J; Stewart, J; Carlsen, T; Callaham, M

    2001-01-26

    This document details procedures to be used when constructing a conceptual terrestrial trophic model for natural gas and oil exploration and production sites. A site conceptual trophic model is intended for use in evaluating ecological impacts of oil and brine releases at E&P sites from a landscape or ecosystem perspective. The terrestrial trophic model protocol was developed using an example site, the Tallgrass Prairie Preserve (TPP) in Oklahoma. The procedure focuses on developing a terrestrial trophic model using information found in the primary literature, and augmented using site-specific research where available. Although the TPP has been the subject of considerable research and public interest since the high-profile reintroduction of bison (Bison bison) in 1993, little formal work has been done to develop a food web for the plant and animal communities found at the preserve. We describe how to divide species into guilds using explicit criteria on the basis of resource use and spatial distribution. For the TPP, sixteen guilds were developed for use in the trophic model, and the relationships among these guilds were analyzed. A brief discussion of the results of this model is provided, along with considerations for its use and areas for further study.

  6. Analysis and Development of the Generic Maintenance Management Process Modeling for the Preservation of Heritage School Buildings

    Directory of Open Access Journals (Sweden)

    A Z. A. Akasah

    2009-12-01

    Full Text Available Preservation of heritage school buildings requires special maintenance management practices. A thorough understanding of the maintenance management process is essential in ensuring effective maintenance practices can be instituted. The aim of this paper was to develop a generic process model that will promote the understanding of an effective management of maintenance process for heritage school buildings. A process model for the Maintenance Management of Heritage School Buildings (MMHSB was developed using the Integration Definition for Function Modeling (IDEF0 system through an iterative process. The initial MMHSB process model was submitted to a team of management experts from the Malaysian Ministry of Arts and Heritage and the Ministry of Education Malaysia for verifications. Based on their feedbacks the initial model was refined and a proposed model was developed. From the second verification, the feed back received formed the basis for the final model. The final model elucidates the items for the input, mechanism, control and output elements that are critical in the maintenance management of heritage school buildings. The model also redefines the existing scope of responsibilities of the Headmasters’ and Senior Assistants’ in the management of maintenance. The perceived effectiveness of the model by potential users was surveyed using a selected number of administrators from potentially recognized heritage schools. The results indicated that the process model is perceived as being helpful in clarifying the maintenance management process of heritage school buildings and is useful in changing the current reactive management practices to that of a more proactive practice. In conclusion, it is believed that the MMHSB Process Model is helpful in promoting the understanding of the maintenance management process which would lead to improve preservation practices of heritage school buildings.

  7. Modes of fossil preservation

    Science.gov (United States)

    Schopf, J.M.

    1975-01-01

    The processes of geologic preservation are important for understanding the organisms represented by fossils. Some fossil differences are due to basic differences in organization of animals and plants, but the interpretation of fossils has also tended to be influenced by modes of preservation. Four modes of preservation generally can be distinguished: (1) Cellular permineralization ("petrifaction") preserves anatomical detail, and, occasionally, even cytologic structures. (2) Coalified compression, best illustrated by structures from coal but characteristic of many plant fossils in shale, preserves anatomical details in distorted form and produces surface replicas (impressions) on enclosing matrix. (3) Authigenic preservation replicates surface form or outline (molds and casts) prior to distortion by compression and, depending on cementation and timing, may intergrade with fossils that have been subject to compression. (4) Duripartic (hard part) preservation is characteristic of fossil skeletal remains, predominantly animal. Molds, pseudomorphs, or casts may form as bulk replacements following dissolution of the original fossil material, usually by leaching. Classification of the kinds of preservation in fossils will aid in identifying the processes responsible for modifying the fossil remains of both animals and plants. ?? 1975.

  8. Relaxin as a protective substance in preservation solutions for organ transplantation, as shown in an isolated perfused rat liver model.

    Science.gov (United States)

    Boehnert, M U; Armbruster, F P; Hilbig, H

    2008-05-01

    Reperfusion injury, a well-known problem in organ transplantation, results from multiple pathologic mechanisms, including platelet/mast cell activation and peroxidation of cell membrane lipids. Relaxin was originally described as an insulin-like hormone produced in the ovaries during pregnancy. It causes vessel dilation and inhibition of platelet and mast cell activation. The present study investigated the protective effect of relaxin against reperfusion injury in liver tissue. We used a model of isolated perfused rat liver to simulate liver transplantation. Organ preservation was performed identical to human transplantation in 20 male Wistar rats. During preservation we applied 64 ng/mL relaxin. In contrast controls (n = 10) had no relaxin treatment. To quantify cell damage, we measured malonyldialdehyde (MDA; end product of lipid peroxidation) and myeloperoxidase activity (MPO; marker for accumulation of neutrophil granulocytes) in the perfusates. The livers were examined immunohistochemically for the same parameters. Relaxin as an additional substance in preservation solutions decreased perfusate MPO and MDA levels by up to 30%, as shown by immunohistochemistry. Our preliminary data suggested that relaxin is a promising agent to reduce hepatocyte damage caused by ischemia-reperfusion injury. Quantitative analysis of MDA and MPO levels in the perfusate is the subject of an ongoing study.

  9. Relative importance of secondary settling tank models in WWTP simulations

    DEFF Research Database (Denmark)

    Ramin, Elham; Flores-Alsina, Xavier; Sin, Gürkan

    2012-01-01

    Results obtained in a study using the Benchmark Simulation Model No. 1 (BSM1) show that a one-dimensional secondary settling tank (1-D SST) model structure and its parameters are among the most significant sources of uncertainty in wastewater treatment plant (WWTP) simulations [Ramin et al., 2011......]. The sensitivity results consistently indicate that the prediction of sludge production is most sensitive to the variation of the settling parameters. In the present study, we use the Benchmark Simulation Model No. 2 (BSM2), a plant-wide benchmark, that combines the Activated Sludge Model No. 1 (ASM1......) with the Anaerobic Digestion Model No. 1 (ADM1). We use BSM2 as a vehicle to compare two different 1-D SST models, and to assess the relative significance of their performance on WWTP simulation model outputs. The two 1-D SST models assessed include the firstorder model by Takács et al. [1991] and the second...

  10. On the importance of recording microforms and digitised versions produced for preservation on the international level, with a focus on standards

    Directory of Open Access Journals (Sweden)

    Werner Schwartz

    2003-11-01

    Full Text Available When we think about preserving our cultural heritage the first thing that comes to mind is how to find ways to properly store and protect the original works of art, literature and science. Our aim is to save them for our time and for generations to come. We wish to restore them in such a way that their original structure and content is respected and remains unaltered while the material is strengthened to withstand the pressure exacted by use, climate and many other hazards. Very notable aims. Reality, however, is quick to bring disillusion. User demand far exceeds our possibilities to sufficiently prepare the original items or even to restore them diligently enough not to alter their originality. True restoration is bound to consume resources and time to such an extent that we cannot but treat only a relatively small number of items.

  11. Importance of Computer Model Validation in Pyroprocessing Technology Development

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Y. E.; Li, Hui; Yim, M. S. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    In this research, we developed a plan for experimental validation of one of the computer models developed for ER process modeling, i. e., the ERAD code. Several candidate surrogate materials are selected for the experiment considering the chemical and physical properties. Molten salt-based pyroprocessing technology is being examined internationally as an alternative to treat spent nuclear fuel over aqueous technology. The central process in pyroprocessing is electrorefining(ER) which separates uranium from transuranic elements and fission products present in spent nuclear fuel. ER is a widely used process in the minerals industry to purify impure metals. Studies of ER by using actual spent nuclear fuel materials are problematic for both technical and political reasons. Therefore, the initial effort for ER process optimization is made by using computer models. A number of models have been developed for this purpose. But as validation of these models is incomplete and often times problematic, the simulation results from these models are inherently uncertain.

  12. Xenografting as a Tool to Preserve Endangered Species: Outcomes and Challenges in Model Systems

    Directory of Open Access Journals (Sweden)

    Paula C. Mota

    2011-01-01

    Full Text Available The use of testis tissue xenografting as a valuable tool to rescue endangered and genetically valuable individuals that die young or otherwise fail to produce sperm has been the subject of much interest. Although the technique has been successfully applied to a wide variety of species, little is known about what determines the outcome. Furthermore, to improve the applicability of xenografting, new methods to preserve and transport testis tissue from valuable animals are emerging. However, one major issue remains: the application of xenografting implies the development of subsequent ART techniques to produce offspring from the recovered material. This paper focuses on these three aspects of testis tissue xenografting as a tool for rescuing endangered and valuable genetic pools.

  13. Bridging between NMA and Elastic Network Models: Preserving All-Atom Accuracy in Coarse-Grained Models.

    Directory of Open Access Journals (Sweden)

    Hyuntae Na

    2015-10-01

    Full Text Available Dynamics can provide deep insights into the functional mechanisms of proteins and protein complexes. For large protein complexes such as GroEL/GroES with more than 8,000 residues, obtaining a fine-grained all-atom description of its normal mode motions can be computationally prohibitive and is often unnecessary. For this reason, coarse-grained models have been used successfully. However, most existing coarse-grained models use extremely simple potentials to represent the interactions within the coarse-grained structures and as a result, the dynamics obtained for the coarse-grained structures may not always be fully realistic. There is a gap between the quality of the dynamics of the coarse-grained structures given by all-atom models and that by coarse-grained models. In this work, we resolve an important question in protein dynamics computations--how can we efficiently construct coarse-grained models whose description of the dynamics of the coarse-grained structures remains as accurate as that given by all-atom models? Our method takes advantage of the sparseness of the Hessian matrix and achieves a high efficiency with a novel iterative matrix projection approach. The result is highly significant since it can provide descriptions of normal mode motions at an all-atom level of accuracy even for the largest biomolecular complexes. The application of our method to GroEL/GroES offers new insights into the mechanism of this biologically important chaperonin, such as that the conformational transitions of this protein complex in its functional cycle are even more strongly connected to the first few lowest frequency modes than with other coarse-grained models.

  14. Bridging between NMA and Elastic Network Models: Preserving All-Atom Accuracy in Coarse-Grained Models.

    Science.gov (United States)

    Na, Hyuntae; Jernigan, Robert L; Song, Guang

    2015-10-01

    Dynamics can provide deep insights into the functional mechanisms of proteins and protein complexes. For large protein complexes such as GroEL/GroES with more than 8,000 residues, obtaining a fine-grained all-atom description of its normal mode motions can be computationally prohibitive and is often unnecessary. For this reason, coarse-grained models have been used successfully. However, most existing coarse-grained models use extremely simple potentials to represent the interactions within the coarse-grained structures and as a result, the dynamics obtained for the coarse-grained structures may not always be fully realistic. There is a gap between the quality of the dynamics of the coarse-grained structures given by all-atom models and that by coarse-grained models. In this work, we resolve an important question in protein dynamics computations--how can we efficiently construct coarse-grained models whose description of the dynamics of the coarse-grained structures remains as accurate as that given by all-atom models? Our method takes advantage of the sparseness of the Hessian matrix and achieves a high efficiency with a novel iterative matrix projection approach. The result is highly significant since it can provide descriptions of normal mode motions at an all-atom level of accuracy even for the largest biomolecular complexes. The application of our method to GroEL/GroES offers new insights into the mechanism of this biologically important chaperonin, such as that the conformational transitions of this protein complex in its functional cycle are even more strongly connected to the first few lowest frequency modes than with other coarse-grained models.

  15. On the importance of hysteresis in hydrological modeling

    Science.gov (United States)

    Gharari, S.; Razavi, S.

    2016-12-01

    Hysteresis is a widely observed phenomenon in hydrology and beyond at a range of spatio-temporal scales. Despite significant research efforts, hysteretic behaviors and their implications for hydrologic modelling and prediction have remained poorly defined and understood. The current state of the art is that almost all practical models in use do not include any hysteretic component or relationship that directly represents such behaviors. In this study, we review different types of hysteretic behaviors in hydrology and formulate a general definition for hysteresis that might be useful in the context of hydrological modeling. We show how hysteresis can be the result of missing (or ignoring) dimensions/physics that govern a real system. Further, using existing strategies for hysteresis modeling from other disciples, we evaluate to what extent the addition of hysteretic components to a hydrological model (such as soil moisture and soil suction head - soil hydraulic conductivity) change the model performance and associated uncertainties. Our analyses also show that properly designed model structures can largely compensate for the lack of hysteretic components in models and allow mimicking the observed hysteretic behaviors.

  16. From UML Activities to TAAL: Towards behaviour-preserving model transformations

    NARCIS (Netherlands)

    Engels, G.; Kleppe, A.G.; Rensink, A.; Semenyak, M.; Soltenborn, Ch.; Wehrheim, H.; Hartman, A.; Schieferdecker, I.

    2008-01-01

    Model transformations support a model-driven design by providing an automatic translation of abstract models into more concrete ones, and eventually program code. Crucial to a successful application of model transformations is their correctness, in the sense that the meaning (semantics) of the model

  17. A Lagrangian model for soil water dynamics: can we step beyond Richard's equation while preserving capillarity as first order control?

    Science.gov (United States)

    Zehe, Erwin; Jackisch, Conrad

    2016-04-01

    Water storage in the unsaturated zone is controlled by capillary forces which increase nonlinearly with decreasing pore size, because water acts as a wetting fluid in soil. The standard approach to represent capillary and gravity controlled soil water dynamics is the Darcy-Richards equation in combination with suitable soil water characteristics. This continuum model essentially assumes capillarity controlled diffusive fluxes to dominate soil water dynamics under local thermodynamic equilibrium conditions. Today we know that the assumptions of local equilibrium conditions e.g. and a mainly diffusive flow are often not appropriate, particularly during rainfall events in structured soils. Rapid or preferential flow imply a strong local disequilibrium and imperfect mixing between a fast fraction of soil water, traveling in interconnected coarse pores or non-capillary macropores, and the slower diffusive flow in finer fractions of the pore space. Although various concepts have been proposed to overcome the inability of the Darcy - Richards concept to cope with not-well mixed preferential flow, we still lack an approach that is commonly accepted. Notwithstanding the listed short comings, one should not mistake the limitations of the Richards equation with non-importance of capillary forces in soil. Without capillarity infiltrating rainfall would drain into groundwater bodies, leaving an empty soil as the local equilibrium state - there would be no soil water dynamics at all, probably even no terrestrial vegetation without capillary forces. Better alternatives for the Darcy-Richards approach are thus highly desirable, as long they preserve the grain of "truth" about capillarity as first order control. Here we propose such an alternative approach to simulate soil moisture dynamics in a stochastic and yet physical way. Soil water is represented by particles of constant mass, which travel according to the Itô form of the Fokker Planck equation. The model concept builds on

  18. On the importance of conserving mass in sea ice models

    CERN Document Server

    Moon, Woosok

    2013-01-01

    We describe how a long standing approach used in the thermodynamic modeling of sea ice fails to conserve mass. The missing mass is traced to a term that is equivalent to neglecting a leading order latent heat flux and we demonstrate its influence using energy balance models with a fractional ice cover. It is shown that this neglect is particularly acute in a decaying ice cover approaching the transitions to seasonal and ice-free conditions. Accordingly, it is suggested that it may be of considerable relevance to re-examine the relevant climate model schemes.

  19. Multi-item economic production quantity model for imperfect items with multiple production setups and rework under the effect of preservation technology and learning environment

    Directory of Open Access Journals (Sweden)

    Preeti Jawla

    2016-09-01

    Full Text Available This study aims to investigate the multi-item inventory model in a production/rework system with multiple production setups. Rework can be depicted as the transformation of production rejects, failed, or non-conforming items into re-usable products of the same or lower quality during or after inspection. Rework is very valuable and profitable, especially if materials are limited in availability and also pricey. Moreover, rework can be a good contribution to a ‘green image environment’. In this paper, we establish a multi-item inventory model to determine the optimal inventory replenishment policy for the economic production quantity (EPQ model for imperfect, deteriorating items with multiple productions and rework under inflation and learning environment. In inventory modelling, Inflation plays a very important role. In one cycle, production system produces items in n production setups and one rework setup, i.e. system follows (n, 1 policy. To reduce the deterioration of products preservation technology investment is also considered in this model. Holding cost is taken as time dependent. We develop expressions for the average profit per time unit, including procurement of input materials, costs for production, rework, deterioration cost and storage of serviceable and reworkable lots. Using those expressions, the proposed model is demonstrated numerically and the sensitivity analysis is also performed to study the behaviour of the model.

  20. Digital Preservation.

    Science.gov (United States)

    Yakel, Elizabeth

    2001-01-01

    Reviews research on digital preservation issues, including born-digital and digitally recreated documents. Discusses electronic records research; metadata and other standards; electronic mail; Web-based documents; moving images media; selection of materials for digitization, including primary sources; administrative issues; media stability…

  1. Clinic expert information extraction based on domain model and block importance model.

    Science.gov (United States)

    Zhang, Yuanpeng; Wang, Li; Qian, Danmin; Geng, Xingyun; Yao, Dengfu; Dong, Jiancheng

    2015-11-01

    To extract expert clinic information from the Deep Web, there are two challenges to face. The first one is to make a judgment on forms. A novel method based on a domain model, which is a tree structure constructed by the attributes of query interfaces is proposed. With this model, query interfaces can be classified to a domain and filled in with domain keywords. Another challenge is to extract information from response Web pages indexed by query interfaces. To filter the noisy information on a Web page, a block importance model is proposed, both content and spatial features are taken into account in this model. The experimental results indicate that the domain model yields a precision 4.89% higher than that of the rule-based method, whereas the block importance model yields an F1 measure 10.5% higher than that of the XPath method.

  2. The importance of structural model availability on seismic interpretation

    Science.gov (United States)

    Alcalde, Juan; Bond, Clare E.; Johnson, Gareth; Butler, Robert W. H.; Cooper, Mark A.; Ellis, Jennifer F.

    2017-04-01

    Interpretation of faults in seismic images is central to the creation of geological models of the subsurface. The use of prior knowledge acquired through learning allows interpreters to move from singular observations to reasoned interpretations based on the conceptual models available to them. The amount and variety of fault examples available in textbooks, articles and training exercises is therefore likely to be a determinant factor in the interpreters' ability to interpret realistic fault geometries in seismic data. We analysed the differences in fault type and geometry interpreted in seismic data by students before and after completing a masters module in structural geology, and compared them to the characteristics of faults represented in the module and textbooks. We propose that the observed over-representation of normal-planar faults in early teaching materials influences the interpretation of data, making this fault type and geometry dominant in the pre-module interpretations. However, when the students were exposed to a greater range in fault models in the module, the range of fault type and geometry increased. This work explores the role of model availability in interpretation and advocates for the use of realistic fault models in training materials.

  3. Spatial correlations in bed load transport: evidence, importance, and modelling

    CERN Document Server

    Heyman, J; Mettra, F; Ancey, C

    2016-01-01

    This article examines the spatial {dynamics of bed load particles} in water. We focus particularly on the fluctuations of particle activity, which is defined as the number of moving particles per unit bed {length}. Based on a stochastic model recently proposed by \\citet{Ancey2013}, we derive the second moment of particle activity analytically; that is the spatial correlation functions of particle activity. From these expressions, we show that large moving particle clusters can develop spatially. Also, we provide evidence that fluctuations of particle activity are scale-dependent. Two characteristic lengths emerge from the model: a saturation length $\\ell_{sat}$ describing the length needed for a perturbation in particle activity to relax to the homogeneous solution, and a correlation length $\\ell_c$ describing the typical size of moving particle clusters. A dimensionless P\\'eclet number can also be defined according to the transport model. Three different experimental data sets are used to test the theoretica...

  4. Exact travelling wave solutions for some important nonlinear physical models

    Indian Academy of Sciences (India)

    Jonu Lee; Rathinasamy Sakthivel

    2013-05-01

    The two-dimensional nonlinear physical models and coupled nonlinear systems such as Maccari equations, Higgs equations and Schrödinger–KdV equations have been widely applied in many branches of physics. So, finding exact travelling wave solutions of such equations are very helpful in the theories and numerical studies. In this paper, the Kudryashov method is used to seek exact travelling wave solutions of such physical models. Further, three-dimensional plots of some of the solutions are also given to visualize the dynamics of the equations. The results reveal that the method is a very effective and powerful tool for solving nonlinear partial differential equations arising in mathematical physics.

  5. Chronopolis Digital Preservation Network

    Directory of Open Access Journals (Sweden)

    David Minor

    2010-07-01

    Full Text Available The Chronopolis Digital Preservation Initiative, one of the Library of Congress’ latest efforts to collect and preserve at-risk digital information, has completed its first year of service as a multi-member partnership to meet the archival needs of a wide range of domains.Chronopolis is a digital preservation data grid framework developed by the San Diego Supercomputer Center (SDSC at UC San Diego, the UC San Diego Libraries (UCSDL, and their partners at the National Center for Atmospheric Research (NCAR in Colorado and the University of Maryland's Institute for Advanced Computer Studies (UMIACS.Chronopolis addresses a critical problem by providing a comprehensive model for the cyberinfrastructure of collection management, in which preserved intellectual capital is easily accessible, and research results, education material, and new knowledge can be incorporated smoothly over the long term. Integrating digital library, data grid, and persistent archive technologies, Chronopolis has created trusted environments that span academic institutions and research projects, with the goal of long-term digital preservation.A key goal of the Chronopolis project is to provide cross-domain collection sharing for long-term preservation. Using existing high-speed educational and research networks and mass-scale storage infrastructure investments, the partnership is leveraging the data storage capabilities at SDSC, NCAR, and UMIACS to provide a preservation data grid that emphasizes heterogeneous and highly redundant data storage systems.In this paper we will explore the major themes within Chronopolis, including:a The philosophy and theory behind a nationally federated data grid for preservation. b The core tools and technologies used in Chronopolis. c The metadata schema that is being developed within Chronopolis for all of the data elements. d Lessons learned from the first year of the project.e Next steps in digital preservation using Chronopolis: how we

  6. Extended K-Anonymity Model for Privacy Preserving on Micro Data

    Directory of Open Access Journals (Sweden)

    Masoud Rahimi

    2015-11-01

    Full Text Available Today, information collectors, particularly statistical organizations, are faced with two conflicting issues. On one hand, according to their natural responsibilities and the increasing demand for the collected data, they are committed to propagate the information more extensively and with higher quality and on the other hand, due to the public concern about the privacy of personal information and the legal responsibility of these organizations in protecting the private information of their users, they should guarantee that while providing all the information to the population, the privacy is reasonably preserved. This issue becomes more crucial when the datasets published by data mining methods are at risk of attribute and identity disclosure attacks. In order to overcome this problem, several approaches, called p-sensitive k-anonymity, p+-sensitive k-anonymity, and (p, α-sensitive k-anonymity, were proposed. The drawbacks of these methods include the inability to protect micro datasets against attribute disclosure and the high value of the distortion ratio. In order to eliminate these drawbacks, this paper proposes an algorithm that fully protects the propagated micro data against identity and attribute disclosure and significantly reduces the distortion ratio during the anonymity process.

  7. Chronic intermittent hypoxia preserves bone density in a mouse model of sleep apnea.

    Science.gov (United States)

    Torres, Marta; Montserrat, Josep M; Pavía, Javier; Dalmases, Mireia; Ros, Domenec; Fernandez, Yolanda; Barbé, Ferran; Navajas, Daniel; Farré, Ramon

    2013-12-01

    Very recent clinical research has investigated whether obstructive sleep apnea (OSA) may modulate bone homeostasis but the few data available are conflicting. Here we report novel data obtained in a mouse study specifically designed to determine whether chronic intermittent hypoxia realistically mimicking OSA modifies bone mineral density (BMD). Normal male and female mice and orchidectomized mice (N=10 each group) were subjected to a pattern of high-frequency intermittent hypoxia (20s at 5% and 40s at 21%, 60 cycles/h) for 6h/day. Identical groups breathing room air (normoxia) were the controls. After 32 days of intermittent hypoxia/normoxia the trabecular bone mineral density (BMD) in the peripheral femora were measured by micro-CT scanning. When compared with normoxia (two-way ANOVA), intermittent hypoxia did not significantly modify BMD in the three animal groups tested. Data in this study suggest that the type of intermittent hypoxia characterizing OSA, applied as a single challenge, preserves bone homeostasis.

  8. Importance of Dynamic Inflow Model Predictive Control of Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Knudsen, Torben; Overgaard, Anders;

    2015-01-01

    The efficiency of including dynamic inflow in the model based design of wind turbine controller has been discussed for many years in the wind energy community with out getting to a safe conclusion. This paper delivers a good argument in favor of including dynamic inflow. The main contributions...

  9. Social Importance Dynamics: A Model for Culturally-Adaptive Agents

    NARCIS (Netherlands)

    Mascarenhas, S.; Prada, R.; Paiva, A.; Hofstede, G.J.

    2013-01-01

    The unwritten rules of human cultures greatly affect social behaviour and as such should be considered in the development of socially intelligent agents. So far, there has been a large focus on modeling cultural aspects related to non-verbal behaviour such as gaze or body posture. However, culture a

  10. The Importance of Formalizing Computational Models of Face Adaptation Aftereffects

    Science.gov (United States)

    Ross, David A.; Palmeri, Thomas J.

    2016-01-01

    Face adaptation is widely used as a means to probe the neural representations that support face recognition. While the theories that relate face adaptation to behavioral aftereffects may seem conceptually simple, our work has shown that testing computational instantiations of these theories can lead to unexpected results. Instantiating a model of face adaptation not only requires specifying how faces are represented and how adaptation shapes those representations but also specifying how decisions are made, translating hidden representational states into observed responses. Considering the high-dimensionality of face representations, the parallel activation of multiple representations, and the non-linearity of activation functions and decision mechanisms, intuitions alone are unlikely to succeed. If the goal is to understand mechanism, not simply to examine the boundaries of a behavioral phenomenon or correlate behavior with brain activity, then formal computational modeling must be a component of theory testing. To illustrate, we highlight our recent computational modeling of face adaptation aftereffects and discuss how models can be used to understand the mechanisms by which faces are recognized. PMID:27378960

  11. On the importance of local connectivity for internet topology models

    NARCIS (Netherlands)

    Haddadi, H.; Fay, D.; Jamakovic, A.; Maennel, O.; Moore, A.W.; Mortier, R.; Uhlig, S.

    2009-01-01

    Existing models for Internet Autonomous System (AS) topology generation make structural assumptions about the AS graph. Those assumptions typically stem from beliefs about the true properties of the Internet, e.g. hierarchy and powerlaws, which arise from incorrect interpretations of incomplete obse

  12. The Importance of Computational Modeling of Large Pumping Stations

    Directory of Open Access Journals (Sweden)

    S. M. Bozh'eva

    2015-01-01

    Full Text Available The article presents main design and structure principles of pumping stations. It specifies basic requirements for the favorable hydraulic operation conditions of the pumping units. The article also describes the designing cases, when computational modeling is necessary to analyse activity of pumping station and provide its reliable operation. A specific example of the large pumping station with submersible pumps describes the process of computational modeling of its operation. As the object of simulation was selected the underground pumping station with a diameter of 26 m and a depth of 13 m, divided into two independent branches, equipped with 8 submersible pumps. The objective of this work was to evaluate the effectiveness of the design solution by CFD methods, to analyze the design of the inlet chamber, to identify possible difficulties with the operation of the facility. In details are described the structure of the considered pumping station and applied computational models of physical processes. The article gives the detailed formulation of the task of simulation and the methods of its solving and presents the initial and boundary conditions. It describes the basic operation modes of the pumping station. The obtained results were presented as the flow patterns for each operation mode with detailed explanations. Data obtained as a result of CFD, prove the correctness of the general design solutions of the project. The submersible pump operation at the minimum water level was verified, was confirmed a lack of vortex formation as well as were proposed measures to improve the operating conditions of the facility. In the inlet chamber there are shown the stagnant zones, requiring separate schedule of cleaning. The measure against floating debris and foam was proposed. It justifies the use of computational modeling (CFD for the verifying and adjusting of the projects of large pumping stations as a much more precise tool that takes into account

  13. Right ventricular nitric oxide signaling in an ovine model of congenital heart disease: a preserved fetal phenotype.

    Science.gov (United States)

    Kameny, Rebecca Johnson; He, Youping; Morris, Catherine; Sun, Christine; Johengen, Michael; Gong, Wenhui; Raff, Gary W; Datar, Sanjeev A; Oishi, Peter E; Fineman, Jeffrey R

    2015-07-01

    We recently reported superior right ventricle (RV) performance in response to acute afterload challenge in lambs with a model of congenital heart disease with chronic left-to-right cardiac shunts. Compared with control animals, shunt lambs demonstrated increased contractility because of an enhanced Anrep effect (the slow increase in contractility following myocyte stretch). This advantageous physiological response may reflect preservation of a fetal phenotype, since the RV of shunt lambs remains exposed to increased pressure postnatally. Nitric oxide (NO) production by NO synthase (NOS) is activated by myocyte stretch and is a necessary intermediary of the Anrep response. The purpose of this study was to test the hypothesis that NO signaling is increased in the RV of fetal lambs compared with controls and shunt lambs have persistence of this fetal pattern. An 8-mm graft was placed between the pulmonary artery and aorta in fetal lambs (shunt). NOS isoform expression, activity, and association with activating cofactors were determined in fetal tissue obtained during late-gestation and in 4-wk-old juvenile shunt and control lambs. We demonstrated increased RNA and protein expression of NOS isoforms and increased total NOS activity in the RV of both shunt and fetal lambs compared with control. We also found increased NOS activation and association with cofactors in shunt and fetal RV compared with control. These data demonstrate preserved fetal NOS phenotype and NO signaling in shunt RV, which may partially explain the mechanism underlying the adaptive response to increased afterload seen in the RV of shunt lambs.

  14. Activation of the molecular chaperone, sigma 1 receptor, preserves cone function in a murine model of inherited retinal degeneration.

    Science.gov (United States)

    Wang, Jing; Saul, Alan; Roon, Penny; Smith, Sylvia B

    2016-06-28

    Retinal degenerative diseases are major causes of untreatable blindness, and novel approaches to treatment are being sought actively. Here we explored the activation of a unique protein, sigma 1 receptor (Sig1R), in the treatment of PRC loss because of its multifaceted role in cellular survival. We used Pde6β(rd10) (rd10) mice, which harbor a mutation in the rod-specific phosphodiesterase gene Pde6β and lose rod and cone photoreceptor cells (PRC) within the first 6 wk of life, as a model for severe retinal degeneration. Systemic administration of the high-affinity Sig1R ligand (+)-pentazocine [(+)-PTZ] to rd10 mice over several weeks led to the rescue of cone function as indicated by electroretinographic recordings using natural noise stimuli and preservation of cone cells upon spectral domain optical coherence tomography and retinal histological examination. The protective effect appears to result from the activation of Sig1R, because rd10/Sig1R(-/-) mice administered (+)-PTZ exhibited no cone preservation. (+)-PTZ treatment was associated with several beneficial cellular phenomena including attenuated reactive gliosis, reduced microglial activation, and decreased oxidative stress in mutant retinas. To our knowledge, this is the first report that activation of Sig1R attenuates inherited PRC loss. The findings may have far-reaching therapeutic implications for retinal neurodegenerative diseases.

  15. Mesenchymal Stem Cells Preserve Working Memory in the 3xTg-AD Mouse Model of Alzheimer's Disease.

    Science.gov (United States)

    Ruzicka, Jiri; Kulijewicz-Nawrot, Magdalena; Rodrigez-Arellano, Jose Julio; Jendelova, Pavla; Sykova, Eva

    2016-01-25

    The transplantation of stem cells may have a therapeutic effect on the pathogenesis and progression of neurodegenerative disorders. In the present study, we transplanted human mesenchymal stem cells (MSCs) into the lateral ventricle of a triple transgenic mouse model of Alzheimer's disease (3xTg-AD) at the age of eight months. We evaluated spatial reference and working memory after MSC treatment and the possible underlying mechanisms, such as the influence of transplanted MSCs on neurogenesis in the subventricular zone (SVZ) and the expression levels of a 56 kDa oligomer of amyloid β (Aβ*56), glutamine synthetase (GS) and glutamate transporters (Glutamate aspartate transporter (GLAST) and Glutamate transporter-1 (GLT-1)) in the entorhinal and prefrontal cortices and the hippocampus. At 14 months of age we observed the preservation of working memory in MSC-treated 3xTg-AD mice, suggesting that such preservation might be due to the protective effect of MSCs on GS levels and the considerable downregulation of Aβ*56 levels in the entorhinal cortex. These changes were observed six months after transplantation, accompanied by clusters of proliferating cells in the SVZ. Since the grafted cells did not survive for the whole experimental period, it is likely that the observed effects could have been transiently more pronounced at earlier time points than at six months after cell application.

  16. Mesenchymal Stem Cells Preserve Working Memory in the 3xTg-AD Mouse Model of Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Jiri Ruzicka

    2016-01-01

    Full Text Available The transplantation of stem cells may have a therapeutic effect on the pathogenesis and progression of neurodegenerative disorders. In the present study, we transplanted human mesenchymal stem cells (MSCs into the lateral ventricle of a triple transgenic mouse model of Alzheimer´s disease (3xTg-AD at the age of eight months. We evaluated spatial reference and working memory after MSC treatment and the possible underlying mechanisms, such as the influence of transplanted MSCs on neurogenesis in the subventricular zone (SVZ and the expression levels of a 56 kDa oligomer of amyloid β (Aβ*56, glutamine synthetase (GS and glutamate transporters (Glutamate aspartate transporter (GLAST and Glutamate transporter-1 (GLT-1 in the entorhinal and prefrontal cortices and the hippocampus. At 14 months of age we observed the preservation of working memory in MSC-treated 3xTg-AD mice, suggesting that such preservation might be due to the protective effect of MSCs on GS levels and the considerable downregulation of Aβ*56 levels in the entorhinal cortex. These changes were observed six months after transplantation, accompanied by clusters of proliferating cells in the SVZ. Since the grafted cells did not survive for the whole experimental period, it is likely that the observed effects could have been transiently more pronounced at earlier time points than at six months after cell application.

  17. Using medical history embedded in biometrics medical card for user identity authentication: privacy preserving authentication model by features matching.

    Science.gov (United States)

    Fong, Simon; Zhuang, Yan

    2012-01-01

    Many forms of biometrics have been proposed and studied for biometrics authentication. Recently researchers are looking into longitudinal pattern matching that based on more than just a singular biometrics; data from user's activities are used to characterise the identity of a user. In this paper we advocate a novel type of authentication by using a user's medical history which can be electronically stored in a biometric security card. This is a sequel paper from our previous work about defining abstract format of medical data to be queried and tested upon authentication. The challenge to overcome is preserving the user's privacy by choosing only the useful features from the medical data for use in authentication. The features should contain less sensitive elements and they are implicitly related to the target illness. Therefore exchanging questions and answers about a few carefully chosen features in an open channel would not easily or directly expose the illness, but yet it can verify by inference whether the user has a record of it stored in his smart card. The design of a privacy preserving model by backward inference is introduced in this paper. Some live medical data are used in experiments for validation and demonstration.

  18. Combining citrulline with atorvastatin preserves glucose homeostasis in a murine model of diet-induced obesity.

    Science.gov (United States)

    Capel, Frédéric; Chabrier, Gwladys; Pitois, Elodie; Rigaudière, Jean-Paul; Le Plenier, Servane; Durand, Christine; Jouve, Chrystèle; de Bandt, Jean-Pascal; Cynober, Luc; Moinard, Christophe; Morio, Béatrice

    2015-10-01

    NO is a crucial regulator of energy and lipid metabolism, whose homeostasis is compromised during obesity. Combination of citrulline and atorvastatin potentiated NO production in vitro. Here we have assessed the effects of this combination in mice with diet-induced obesity (DIO). C57BL/6J male mice were given a standard diet (control) or a high fat-high sucrose diet (DIO) for 8 weeks. DIO mice were then treated with DIO alone, DIO with citrulline, DIO with atorvastatin or DIO with citrulline and atorvastatin (DIOcit-stat) for 3 weeks. Thereafter, body composition, glucose tolerance, insulin sensitivity and liver fat metabolism were measured. DIOcit-stat mice showed lower body weight, fat mass and epididymal fat depots compared with other DIO groups. Unlike other DIO groups, glucose tolerance and insulin sensitivity of DIOcit-stat, along with blood glucose and insulin concentrations in response to feeding, were restored to control values. Refeeding-induced changes in liver lipogenic activity were also reduced in DIOcit-stat mice compared with those of DIO animals. This was associated with decreased gene expression of the transcription factor SREBP-1, liver X receptor α, ChREBP and of target lipogenic enzymes in the liver of DIOcit-stat mice compared with those of other DIO groups. The citrulline-atorvastatin combination prevented fat mass accumulation and maintained glucose homeostasis in DIO mice. Furthermore, it potentiated inhibition of hepatic de novo lipogenesis activity. This combination has potential for preservation of glucose homeostasis in patients receiving statin therapy. © 2015 The British Pharmacological Society.

  19. 57Fe Mössbauer spectroscopy used to develop understanding of a diamond preservation index model

    Science.gov (United States)

    Yambissa, M. T.; Forder, S. D.; Bingham, P. A.

    2016-12-01

    57Fe Mössbauer spectroscopy has provided precise and accurate iron redox ratios Fe2+/Fe3+ in ilmenite, FeTiO3, found within kimberlite samples from the Catoca and Camatxia kimberlite pipes from N.E. Angola. Ilmenite is one of the key indicator minerals for diamond survival and it is also one of the iron-bearing minerals with iron naturally occurring in one or both of the oxidation states Fe3+ and Fe2+. For this reason it is a good indicator for studying oxygen fugacities ( fO2) in mineral samples, which can then be related to iron redox ratios, Fe2+/Fe3+. In this paper we demonstrate that the oxidation state of the ilmenite mineral inclusion from sampled kimberlite rock is a key indicator of the oxidation state of the host kimberlite assemblage, which in turn determines the genesis of diamond, grade variation and diamond quality. Ilmenite samples from the two different diamondiferous kimberlite localities (Catoca and Camatxia) in the Lucapa graben, N.E. Angola, were studied using Mössbauer spectroscopy and X-Ray Diffractometry, in order to infer the oxidation state of their source regions in the mantle, oxygen partial pressure and diamond preservation conditions. The iron redox ratios, obtained using Mössbauer spectroscopy, show that the Catoca diamond kimberlite is more oxidised than kimberlite found in the Camatxia pipe, which is associated within the same geological tectonic structure. Here we demonstrate that57Fe Mössbauer spectroscopy can assist geologists and mining engineers to effectively evaluate and determine whether kimberlite deposits are economically feasible for diamond mining.

  20. Arrhenius equation modeling for the shelf life prediction of tomato paste containing a natural preservative.

    Science.gov (United States)

    Jafari, Seid Mahdi; Ganje, Mohammad; Dehnad, Danial; Ghanbari, Vahid; Hajitabar, Javad

    2017-04-28

    The shelf life of tomato paste with microencapsulated olive leaf extract was compared with that of samples containing a commercial preservative by accelerated shelf life testing. Based on previous studies showing that olive leaf extract as a rich source of phenolic compounds can have antimicrobial properties, application of its encapsulated form to improve the storage stability of tomato paste is proposed here. Regarding total soluble solids, the control and the sample containing 1000 µg g(-1) sodium benzoate had the lowest (Q10  = 1.63) and highest (Q10  = 1.88) sensitivity to temperature changes respectively; also, the microencapsulated sample containing 1000 µg g(-1) encapsulated olive leaf extract (Q10  = 1.83) followed the sample containing 1000 µg g(-1) sodium benzoate in terms of the highest kinetic rates. In the case of consistency, the lowest and highest activation energies (Ea ) corresponded to samples containing 1000 µg g(-1) non-encapsulated olive leaf extract and 1000 µg g(-1) microencapsulated olive leaf extract respectively. Interestingly, samples containing microencapsulated olive leaf extract could maintain the original quality of the tomato paste very well, while those with non-encapsulated olive leaf extract rated the worst performance (among all specimens) in terms of maintaining their quality indices for a long time period. Overall, the shelf life equation was able to predict the consistency index of all tomato paste samples during long-time storage with high precision. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Preserving Chile

    OpenAIRE

    Brennand, Charlotte P.

    2010-01-01

    The best way to preserve chile depends on how you plan to use it and your available storage space. Frozen or canned chile is best for chile rellenos and salsas. Stews can use frozen, canned or dried chile. Dried chile has minimal storage requirements and is light-weight for taking on camping trips. Pickled chiles can be used on a relish plate or as an ingredient in other dishes.

  2. Importance of Sea Ice for Validating Global Climate Models

    Science.gov (United States)

    Geiger, Cathleen A.

    1997-01-01

    Reproduction of current day large-scale physical features and processes is a critical test of global climate model performance. Without this benchmark, prognoses of future climate conditions are at best speculation. A fundamental question relevant to this issue is, which processes and observations are both robust and sensitive enough to be used for model validation and furthermore are they also indicators of the problem at hand? In the case of global climate, one of the problems at hand is to distinguish between anthropogenic and naturally occuring climate responses. The polar regions provide an excellent testing ground to examine this problem because few humans make their livelihood there, such that anthropogenic influences in the polar regions usually spawn from global redistribution of a source originating elsewhere. Concomitantly, polar regions are one of the few places where responses to climate are non-anthropogenic. Thus, if an anthropogenic effect has reached the polar regions (e.g. the case of upper atmospheric ozone sensitivity to CFCs), it has most likely had an impact globally but is more difficult to sort out from local effects in areas where anthropogenic activity is high. Within this context, sea ice has served as both a monitoring platform and sensitivity parameter of polar climate response since the time of Fridtjof Nansen. Sea ice resides in the polar regions at the air-sea interface such that changes in either the global atmospheric or oceanic circulation set up complex non-linear responses in sea ice which are uniquely determined. Sea ice currently covers a maximum of about 7% of the earth's surface but was completely absent during the Jurassic Period and far more extensive during the various ice ages. It is also geophysically very thin (typically global climate.

  3. Preserving the Public Good: Presenting an Organizational Model for the Changing Future of Higher Education

    Science.gov (United States)

    Garcia, Stephanie Parra

    2011-01-01

    Institutions of higher education face financial pressure to become self-sustaining (Gumport, 2001; 2000). This rapidly growing economic demand is negatively affecting the social mission of higher education (Kezar, 2004). Scholars suggest the implementation of a new model of higher education, one that blends a for-profit model with the traditional…

  4. A linear programming model for preserving privacy when disclosing patient spatial information for secondary purposes

    Science.gov (United States)

    2014-01-01

    Background A linear programming (LP) model was proposed to create de-identified data sets that maximally include spatial detail (e.g., geocodes such as ZIP or postal codes, census blocks, and locations on maps) while complying with the HIPAA Privacy Rule’s Expert Determination method, i.e., ensuring that the risk of re-identification is very small. The LP model determines the transition probability from an original location of a patient to a new randomized location. However, it has a limitation for the cases of areas with a small population (e.g., median of 10 people in a ZIP code). Methods We extend the previous LP model to accommodate the cases of a smaller population in some locations, while creating de-identified patient spatial data sets which ensure the risk of re-identification is very small. Results Our LP model was applied to a data set of 11,740 postal codes in the City of Ottawa, Canada. On this data set we demonstrated the limitations of the previous LP model, in that it produces improbable results, and showed how our extensions to deal with small areas allows the de-identification of the whole data set. Conclusions The LP model described in this study can be used to de-identify geospatial information for areas with small populations with minimal distortion to postal codes. Our LP model can be extended to include other information, such as age and gender. PMID:24885457

  5. On the importance of having accurate data for astrophysical modelling

    Science.gov (United States)

    Lique, Francois

    2016-06-01

    The Herschel telescope and the ALMA and NOEMA interferometers have opened new windows of observation for wavelengths ranging from far infrared to sub-millimeter with spatial and spectral resolutions previously unmatched. To make the most of these observations, an accurate knowledge of the physical and chemical processes occurring in the interstellar and circumstellar media is essential.In this presentation, I will discuss what are the current needs of astrophysics in terms of molecular data and I will show that accurate molecular data are crucial for the proper determination of the physical conditions in molecular clouds.First, I will focus on collisional excitation studies that are needed for molecular lines modelling beyond the Local Thermodynamic Equilibrium (LTE) approach. In particular, I will show how new collisional data for the HCN and HNC isomers, two tracers of star forming conditions, have allowed solving the problem of their respective abundance in cold molecular clouds. I will also present the last collisional data that have been computed in order to analyse new highly resolved observations provided by the ALMA interferometer.Then, I will present the calculation of accurate rate constants for the F+H2 → HF+H and Cl+H2 ↔ HCl+H reactions, which have allowed a more accurate determination of the physical conditions in diffuse molecular clouds. I will also present the recent work on the ortho-para-H2 conversion due to hydrogen exchange that allow more accurate determination of the ortho-to-para-H2 ratio in the universe and that imply a significant revision of the cooling mechanism in astrophysical media.

  6. Analysis Preservation and Systematic Reinterpretation within the ATLAS Experiment

    CERN Document Server

    Heinrich, Lukas; The ATLAS collaboration

    2017-01-01

    The LHC data analysis software used in order to derive and publish experimental results is an important asset that is necessary to preserve in order to fully exploit the scientific potential of a given measurement. Among others, important use cases of analysis preservation are the reproducibility of the original results and the reusability of the analysis procedure in the context of new scientific studies. A prominent use-case for the latter is the systematic reinterpretation of searches for new Physics in terms of signal models that not studied in the original publication (RECAST). This paper presents the usage of the graph-based workflow description language yadage to drive the reinterpretation of preserved HEP analyses. The analysis software for individual states in the analysis is preserved using Docker containers, while the workflow structure is preserved using plain JSON documents. This allows the re-execution of complex analysis workflows on industry standard container-based distributed computing clust...

  7. A stochastic asymptotic-preserving scheme for a kinetic-fluid model for disperse two-phase flows with uncertainty

    Science.gov (United States)

    Jin, Shi; Shu, Ruiwen

    2017-04-01

    In this paper we consider a kinetic-fluid model for disperse two-phase flows with uncertainty. We propose a stochastic asymptotic-preserving (s-AP) scheme in the generalized polynomial chaos stochastic Galerkin (gPC-sG) framework, which allows the efficient computation of the problem in both kinetic and hydrodynamic regimes. The s-AP property is proved by deriving the equilibrium of the gPC version of the Fokker-Planck operator. The coefficient matrices that arise in a Helmholtz equation and a Poisson equation, essential ingredients of the algorithms, are proved to be positive definite under reasonable and mild assumptions. The computation of the gPC version of a translation operator that arises in the inversion of the Fokker-Planck operator is accelerated by a spectrally accurate splitting method. Numerical examples illustrate the s-AP property and the efficiency of the gPC-sG method in various asymptotic regimes.

  8. A stochastic asymptotic-preserving scheme for a kinetic-fluid model for disperse two-phase flows with uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Shi, E-mail: sjin@wisc.edu [Department of Mathematics, University of Wisconsin–Madison, Madison, WI 53706 (United States); Institute of Natural Sciences, School of Mathematical Science, MOELSEC and SHL-MAC, Shanghai Jiao Tong University, Shanghai 200240 (China); Shu, Ruiwen, E-mail: rshu2@math.wisc.edu [Department of Mathematics, University of Wisconsin–Madison, Madison, WI 53706 (United States)

    2017-04-15

    In this paper we consider a kinetic-fluid model for disperse two-phase flows with uncertainty. We propose a stochastic asymptotic-preserving (s-AP) scheme in the generalized polynomial chaos stochastic Galerkin (gPC-sG) framework, which allows the efficient computation of the problem in both kinetic and hydrodynamic regimes. The s-AP property is proved by deriving the equilibrium of the gPC version of the Fokker–Planck operator. The coefficient matrices that arise in a Helmholtz equation and a Poisson equation, essential ingredients of the algorithms, are proved to be positive definite under reasonable and mild assumptions. The computation of the gPC version of a translation operator that arises in the inversion of the Fokker–Planck operator is accelerated by a spectrally accurate splitting method. Numerical examples illustrate the s-AP property and the efficiency of the gPC-sG method in various asymptotic regimes.

  9. Plant Growth Modelling and Applications: The Increasing Importance of Plant Architecture in Growth Models

    Science.gov (United States)

    Fourcaud, Thierry; Zhang, Xiaopeng; Stokes, Alexia; Lambers, Hans; Körner, Christian

    2008-01-01

    Background Modelling plant growth allows us to test hypotheses and carry out virtual experiments concerning plant growth processes that could otherwise take years in field conditions. The visualization of growth simulations allows us to see directly and vividly the outcome of a given model and provides us with an instructive tool useful for agronomists and foresters, as well as for teaching. Functional–structural (FS) plant growth models are nowadays particularly important for integrating biological processes with environmental conditions in 3-D virtual plants, and provide the basis for more advanced research in plant sciences. Scope In this viewpoint paper, we ask the following questions. Are we modelling the correct processes that drive plant growth, and is growth driven mostly by sink or source activity? In current models, is the importance of soil resources (nutrients, water, temperature and their interaction with meristematic activity) considered adequately? Do classic models account for architectural adjustment as well as integrating the fundamental principles of development? Whilst answering these questions with the available data in the literature, we put forward the opinion that plant architecture and sink activity must be pushed to the centre of plant growth models. In natural conditions, sinks will more often drive growth than source activity, because sink activity is often controlled by finite soil resources or developmental constraints. PMA06 This viewpoint paper also serves as an introduction to this Special Issue devoted to plant growth modelling, which includes new research covering areas stretching from cell growth to biomechanics. All papers were presented at the Second International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications (PMA06), held in Beijing, China, from 13–17 November, 2006. Although a large number of papers are devoted to FS models of agricultural and forest crop species, physiological and genetic

  10. Non-image-forming light driven functions are preserved in a mouse model of autosomal dominant optic atrophy.

    Science.gov (United States)

    Perganta, Georgia; Barnard, Alun R; Katti, Christiana; Vachtsevanos, Athanasios; Douglas, Ron H; MacLaren, Robert E; Votruba, Marcela; Sekaran, Sumathi

    2013-01-01

    Autosomal dominant optic atrophy (ADOA) is a slowly progressive optic neuropathy that has been associated with mutations of the OPA1 gene. In patients, the disease primarily affects the retinal ganglion cells (RGCs) and causes optic nerve atrophy and visual loss. A subset of RGCs are intrinsically photosensitive, express the photopigment melanopsin and drive non-image-forming (NIF) visual functions including light driven circadian and sleep behaviours and the pupil light reflex. Given the RGC pathology in ADOA, disruption of NIF functions might be predicted. Interestingly in ADOA patients the pupil light reflex was preserved, although NIF behavioural outputs were not examined. The B6; C3-Opa1(Q285STOP) mouse model of ADOA displays optic nerve abnormalities, RGC dendropathy and functional visual disruption. We performed a comprehensive assessment of light driven NIF functions in this mouse model using wheel running activity monitoring, videotracking and pupillometry. Opa1 mutant mice entrained their activity rhythm to the external light/dark cycle, suppressed their activity in response to acute light exposure at night, generated circadian phase shift responses to 480 nm and 525 nm pulses, demonstrated immobility-defined sleep induction following exposure to a brief light pulse at night and exhibited an intensity dependent pupil light reflex. There were no significant differences in any parameter tested relative to wildtype littermate controls. Furthermore, there was no significant difference in the number of melanopsin-expressing RGCs, cell morphology or melanopsin transcript levels between genotypes. Taken together, these findings suggest the preservation of NIF functions in Opa1 mutants. The results provide support to growing evidence that the melanopsin-expressing RGCs are protected in mitochondrial optic neuropathies.

  11. Non-image-forming light driven functions are preserved in a mouse model of autosomal dominant optic atrophy.

    Directory of Open Access Journals (Sweden)

    Georgia Perganta

    Full Text Available Autosomal dominant optic atrophy (ADOA is a slowly progressive optic neuropathy that has been associated with mutations of the OPA1 gene. In patients, the disease primarily affects the retinal ganglion cells (RGCs and causes optic nerve atrophy and visual loss. A subset of RGCs are intrinsically photosensitive, express the photopigment melanopsin and drive non-image-forming (NIF visual functions including light driven circadian and sleep behaviours and the pupil light reflex. Given the RGC pathology in ADOA, disruption of NIF functions might be predicted. Interestingly in ADOA patients the pupil light reflex was preserved, although NIF behavioural outputs were not examined. The B6; C3-Opa1(Q285STOP mouse model of ADOA displays optic nerve abnormalities, RGC dendropathy and functional visual disruption. We performed a comprehensive assessment of light driven NIF functions in this mouse model using wheel running activity monitoring, videotracking and pupillometry. Opa1 mutant mice entrained their activity rhythm to the external light/dark cycle, suppressed their activity in response to acute light exposure at night, generated circadian phase shift responses to 480 nm and 525 nm pulses, demonstrated immobility-defined sleep induction following exposure to a brief light pulse at night and exhibited an intensity dependent pupil light reflex. There were no significant differences in any parameter tested relative to wildtype littermate controls. Furthermore, there was no significant difference in the number of melanopsin-expressing RGCs, cell morphology or melanopsin transcript levels between genotypes. Taken together, these findings suggest the preservation of NIF functions in Opa1 mutants. The results provide support to growing evidence that the melanopsin-expressing RGCs are protected in mitochondrial optic neuropathies.

  12. The measurement problem resolved and local realism preserved via a collapse-free photon detection model

    Science.gov (United States)

    Gilbert, Barry C.; Sulcs, Sue

    1996-11-01

    A new realislic local model of light propagation and detection is described. The authors propose a novel stochastic model of low-intensity photon detection in which background noise is added to a part of the photon prior to absorption. In this model, in agreement with Planck, there is no quantization of the propagating field. The model has some similarities to theories advanced by E. Santos and T. Marshall in the last decade, but also has substantial deviations from these. A mechanism, conserving energy and momentum, is proposed by which a sudden collapse of the wave-packet is avoided. The experimental Bell inequality violation of Aspect. Grangier and Roger [Phys. Rev. Lett. 47, 460 (1981)] is discussed. The authors have carried out a computer simulation of a radio frequency (RF) analogue of the Einstein-Podolsky-Rosen thought experiment to illustrate how the manipulation of certain factors, especially signal to noise ratio, detector threshold and characteristics of the noise, enables the same Bell inequality to be either satisfied or violated by a realistic local model. Building on arguments by Santos. [Phys. Rev. A 46. 3646 (1992)], the appropriateness of this Bell lest is discussed. Neither the authors' stochastic-optical model, nor their RF analogue, involves an enhancement assumption of the type defined by Clauser and Horne [Phys. Rev. D 10, 526 (1974)].

  13. Medical physics in radiotherapy: The importance of preserving clinical responsibilities and expanding the profession's role in research, education, and quality control

    Science.gov (United States)

    Malicki, Julian

    2015-01-01

    Medical physicists have long had an integral role in radiotherapy. In recent decades, medical physicists have slowly but surely stepped back from direct clinical responsibilities in planning radiotherapy treatments while medical dosimetrists have assumed more responsibility. In this article, I argue against this gradual withdrawal from routine therapy planning. It is essential that physicists be involved, at least to some extent, in treatment planning and clinical dosimetry for each and every patient; otherwise, physicists can no longer be considered clinical specialists. More importantly, this withdrawal could negatively impact treatment quality and patient safety. Medical physicists must have a sound understanding of human anatomy and physiology in order to be competent partners to radiation oncologists. In addition, they must possess a thorough knowledge of the physics of radiation as it interacts with body tissues, and also understand the limitations of the algorithms used in radiotherapy. Medical physicists should also take the lead in evaluating emerging challenges in quality and safety of radiotherapy. In this sense, the input of physicists in clinical audits and risk assessment is crucial. The way forward is to proactively take the necessary steps to maintain and advance our important role in clinical medicine. PMID:25949219

  14. Medical physics in radiotherapy: The importance of preserving clinical responsibilities and expanding the profession's role in research, education, and quality control.

    Science.gov (United States)

    Malicki, Julian

    2015-01-01

    Medical physicists have long had an integral role in radiotherapy. In recent decades, medical physicists have slowly but surely stepped back from direct clinical responsibilities in planning radiotherapy treatments while medical dosimetrists have assumed more responsibility. In this article, I argue against this gradual withdrawal from routine therapy planning. It is essential that physicists be involved, at least to some extent, in treatment planning and clinical dosimetry for each and every patient; otherwise, physicists can no longer be considered clinical specialists. More importantly, this withdrawal could negatively impact treatment quality and patient safety. Medical physicists must have a sound understanding of human anatomy and physiology in order to be competent partners to radiation oncologists. In addition, they must possess a thorough knowledge of the physics of radiation as it interacts with body tissues, and also understand the limitations of the algorithms used in radiotherapy. Medical physicists should also take the lead in evaluating emerging challenges in quality and safety of radiotherapy. In this sense, the input of physicists in clinical audits and risk assessment is crucial. The way forward is to proactively take the necessary steps to maintain and advance our important role in clinical medicine.

  15. Preservation Priority

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China ratified the UNESCO Convention Concerning the Protection of World Cultural and Natural Heritage in 1985. This set the tone for a course of action aimed at protecting the common heritage of mankind in tandem with the international community. Recently, Chao Huashan, a renowned expert on world heritage studies in China, spoke to Beijing Review reporter Zan Jifang, sharing his understanding about the value of the World Heritage Convention and his suggestions for China’s future work on preserving its heritage. Excerpts follow:

  16. A 3D modeling and measurement system for cultural heritage preservation

    Science.gov (United States)

    Du, Guoguang; Zhou, Mingquan; Ren, Pu; Shui, Wuyang; Zhou, Pengbo; Wu, Zhongke

    2015-07-01

    Cultural Heritage reflects the human production, life style and environmental conditions of various historical periods. It exists as one of the major national carriers of national history and culture. In order to do better protection and utilization for these cultural heritages, a system of three-dimensional (3D) reconstruction and statistical measurement is proposed in this paper. The system solves the problems of cultural heritage's data storage, measurement and analysis. Firstly, for the high precision modeling and measurement problems, range data registration and integration algorithm used to achieve high precision 3D reconstruction. Secondly, multi-view stereo reconstruction method is used to solve the problem of rapid reconstruction by procedures such as the original image data pre-processing, camera calibration, point cloud modeling. At last, the artifacts' measure underlying database is established by calculating the measurements of the 3D model's surface. These measurements contain Euclidean distance between the points on the surface, geodesic distance between the points, normal and curvature in each point, superficial area of a region, volume of model's part and some other measurements. These measurements provide a basis for carrying out information mining of cultural heritage. The system has been applied to the applications of 3D modeling, data measurement of the Terracotta Warriors relics, Tibetan architecture and some other relics.

  17. A linear programming model for preserving privacy when disclosing patient spatial information for secondary purposes

    OpenAIRE

    Jung, Ho-Won; El Emam, Khaled

    2014-01-01

    Background A linear programming (LP) model was proposed to create de-identified data sets that maximally include spatial detail (e.g., geocodes such as ZIP or postal codes, census blocks, and locations on maps) while complying with the HIPAA Privacy Rule’s Expert Determination method, i.e., ensuring that the risk of re-identification is very small. The LP model determines the transition probability from an original location of a patient to a new randomized location. However, it has a limitati...

  18. Three-Dimensional Model for Preservation and Restoration of Architectural Heritage

    Science.gov (United States)

    Marchis, Elena

    2011-01-01

    Thc aim of the research will be to create a model, three-dimensional mathematical. implementation. consultation and assistance to "large" restoration projects that will assist the structural analysis, allowing easier display of dynamic strain. analysis and lighting noise. It could also be a valuable tool for decision support. therefore. may simulate several possible scenarios for intervention, This model appears therefore an excellent support for recovering. ordering and monitoring information about materials and data (stage of restoration. photographs. sampling points. results of diagnostic tests, etc.) collected dynamically during the "life" of the cultural heritage. allowing to document its complete history

  19. The ghost of extinction: Preservation values and minimum viable population in wildlife models

    NARCIS (Netherlands)

    Eiswerth, M.E.; Kooten, van G.C.

    2009-01-01

    The inclusion of a minimum viable population in bioeconomic modeling creates at least two complications that are not resolved by using a modified logistic growth function. The first complication can be dealt with by choosing a different depensational growth function. The second complication relates

  20. Hypercapnic Acidosis Preserves Gastric Mucosal Microvascular Oxygen Saturation in a Canine Model of Hemorrhage.

    NARCIS (Netherlands)

    Schwartges, Ingo; Picker, Olaf; Beck, Christopher; Scheeren, Thomas W. L.; Schwarte, Lothar A.

    2010-01-01

    The authors aimed to clarify the effects of hypercapnic acidosis and its timing on gastric mucosal oxygenation in a canine model of hemorrhage. This was designed as a prospective, controlled, randomized animal study set in a university research laboratory. Five chronically instrumented dogs were

  1. The historical importance and architectonic relevance of the applications of the "extinct" Arrabida Breccia - proposals for its preservation and future uses

    Science.gov (United States)

    Kullberg, José; Prego, António

    2017-04-01

    The upper Oxfordian Arrábida Breccia is a unique lithological type in Portugal and probably in the world because it was formed through several particular geological conditions acting simultaneously. The rock is a conglomerate composed of carbonate pebbles of different colors, cemented by a red, ferruginous, clayey carbonate. It is the expression of a fossilized karst that marks one of the major unconformities of the Lusitanian Basin, associated with the early stages of the opening of the North Atlantic. The use of Arrábida Breccia dates back to Roman times, as a structural element. But it was from the fifteenth century onwards that its use gained importance, mainly as an architectural element during the Manueline period (the end of the Gothic) and, later, during the Baroque, as a decorative element. The exploration of this ornamental stone ended in 1973 with the creation of the Arrábida Natural Park. The Arrábida Breccia assumes a structural and ornamental preponderance in the building up of Jesus Monastery, in the city of Setúbal. This monument has great importance in the portuguese artistic panorama, since that is the forerunner of Manueline arquitecture. One of the key episodes of national history was held in this monastery in 1494: the ratification of the Treaty of Tordesillas, the agreement between Spain and Portugal aimed at settling conflicts over lands newly discovered throughout the world. There are several examples Arrábida Breccia applications in other monuments, that form part of the national heritage. Most of them were built at the reign of king Manuel I (1469 - 1521), that had a personal preference for this rock. There are also vestiges of the use of Arrábida Breccia in a few emblematic buildings of this reign that have been destroyed by the great earthquake of Lisbon, in 1755. Some uses of the Arrábida Breccia are known beyond Portuguese borders, namely in Spain and Brazil. And there is a possible more extensive use in France, within the

  2. Normothermic Perfusion in the Assessment and Preservation of Declined Livers Before Transplantation: Hyperoxia and Vasoplegia-Important Lessons From the First 12 Cases.

    Science.gov (United States)

    Watson, Christopher J E; Kosmoliaptsis, Vasilis; Randle, Lucy V; Gimson, Alexander E; Brais, Rebecca; Klinck, John R; Hamed, Mazin; Tsyben, Anastasia; Butler, Andrew J

    2017-05-01

    A program of normothermic ex situ liver perfusion (NESLiP) was developed to facilitate better assessment and use of marginal livers, while minimizing cold ischemia. Declined marginal livers and those offered for research were evaluated. Normothermic ex situ liver perfusion was performed using an erythrocyte-based perfusate. Viability was assessed with reference to biochemical changes in the perfusate. Twelve livers (9 donation after circulatory death [DCD] and 3 from brain-dead donors), median Donor Risk Index 2.15, were subjected to NESLiP for a median 284 minutes (range, 122-530 minutes) after an initial cold storage period of 427 minutes (range, 222-877 minutes). The first 6 livers were perfused at high perfusate oxygen tensions, and the subsequent 6 at near-physiologic oxygen tensions. After transplantation, 5 of the first 6 recipients developed postreperfusion syndrome and 4 had sustained vasoplegia; 1 recipient experienced primary nonfunction in conjunction with a difficult explant. The subsequent 6 liver transplants, with livers perfused at lower oxygen tensions, reperfused uneventfully. Three DCD liver recipients developed cholangiopathy, and this was associated with an inability to produce an alkali bile during NESLiP. Normothermic ex situ liver perfusion enabled assessment and transplantation of 12 livers that may otherwise not have been used. Avoidance of hyperoxia during perfusion may prevent postreperfusion syndrome and vasoplegia, and monitoring biliary pH, rather than absolute bile production, may be important in determining the likelihood of posttransplant cholangiopathy. Normothermic ex situ liver perfusion has the potential to increase liver utilization, but more work is required to define factors predicting good outcomes.

  3. A reference data model of a metadata registry preserving semantics and representations of data elements.

    Science.gov (United States)

    Löpprich, Martin; Jones, Jennifer; Meinecke, Marie-Claire; Goldschmidt, Hartmut; Knaup, Petra

    2014-01-01

    Integration and analysis of clinical data collected in multiple data sources over a long period of time is a major challenge even when data warehouses and metadata registries are used. Since most metadata registries focus on describing data elements to establish domain consistent data definition and providing item libraries, hierarchical and temporal dependencies cannot be mapped. Therefore we developed and validated a reference data model, based on ISO/IEC 11179, which allows revision and branching control of conceptually similar data elements with heterogeneous definitions and representations.

  4. Antimicrobial effect of natural preservatives in a cooked and acidified chicken meat model.

    Science.gov (United States)

    Lemay, Marie-Josée; Choquette, Julie; Delaquis, Pascal J; Claude, Gariépy; Rodrigue, Natalie; Saucier, Linda

    2002-10-25

    The inhibitory effect of Microgard 100, Microgard 300, nisin, Alta 2002, Perlac 1902, sodium lactate and essential oil of mustard on microorganisms experimentally inoculated was screened in an acidified chicken meat model (pH = 5.0) and stored for 2 weeks at a none restrictive growth temperature of 22 degrees C. All antimicrobials tested were used at the highest concentration recommended by their manufacturer. Sausage batter made with mechanically deboned chicken was inoculated with a mixed culture of Escherichia coli ATCC 25922, Brochothrix thermosphacta CRDAV452, and a protective culture Lactobacillus alimentarius BJ33 (FloraCan L-2). A final cell concentration of 3-4 log CFU g (-1) was targeted after cooking at a core temperature of 55 degrees C for each microorganism in order to assess cell count variation effectively. Composition, water activity (a(w)), pH and redox potential of the sausage model was also evaluated. The E. coli population decreased steadily during storage and was close or below detection level (oil of mustard was used, aerobic mesophilic bacteria and lactic acid bacteria were significantly lower than the control after 2 days of storage (P < or = 0.05). The other antimicrobial agents tested had no significant effect on the aerobic mesophilic bacteria, E. coli, B. thermosphacta and lactic acid bacteria counts, when compared to the control.

  5. Parametric Accuracy: Building Information Modeling Process Applied to the Cultural Heritage Preservation

    Science.gov (United States)

    Garagnani, S.; Manferdini, A. M.

    2013-02-01

    Since their introduction, modeling tools aimed to architectural design evolved in today's "digital multi-purpose drawing boards" based on enhanced parametric elements able to originate whole buildings within virtual environments. Semantic splitting and elements topology are features that allow objects to be "intelligent" (i.e. self-aware of what kind of element they are and with whom they can interact), representing this way basics of Building Information Modeling (BIM), a coordinated, consistent and always up to date workflow improved in order to reach higher quality, reliability and cost reductions all over the design process. Even if BIM was originally intended for new architectures, its attitude to store semantic inter-related information can be successfully applied to existing buildings as well, especially if they deserve particular care such as Cultural Heritage sites. BIM engines can easily manage simple parametric geometries, collapsing them to standard primitives connected through hierarchical relationships: however, when components are generated by existing morphologies, for example acquiring point clouds by digital photogrammetry or laser scanning equipment, complex abstractions have to be introduced while remodeling elements by hand, since automatic feature extraction in available software is still not effective. In order to introduce a methodology destined to process point cloud data in a BIM environment with high accuracy, this paper describes some experiences on monumental sites documentation, generated through a plug-in written for Autodesk Revit and codenamed GreenSpider after its capability to layout points in space as if they were nodes of an ideal cobweb.

  6. Data Preservation

    Directory of Open Access Journals (Sweden)

    Carlo Meghini

    2013-07-01

    Full Text Available Digital information is a vital resource in our knowledge economy, valuable for research and education, science and the humanities, creative and cultural activities, and public policy (The Blue Ribbon Task Force on Sustainable Digital Preservation and Access, 2010. New high-throughput instruments, telescopes, satellites, accelerators, supercomputers, sensor networks, and running simulations are generating massive amounts of data (Thanos, 2011. These data are used by decision makers for improving the quality of life of citizens. Moreover, researchers are employing sophisticated technologies to analyse these data to address questions that were unapproachable just a few years ago (Helbing & Balietti, 2011. Digital technologies have fostered a new world of research characterized by immense datasets, unprecedented levels of openness among researchers, and new connections among researchers, policy makers, and the public (The National Academy of Sciences, 2009.

  7. Power Preservation

    DEFF Research Database (Denmark)

    Galster, Kjeld

    Power Preservation (Abstract) In the 17th century, just as today, coalitions needed ‘lead nations’. This was assumed to be a power with great military and economic potentials, and Denmark endeavoured to act as such a leader in the Thirty Years War from 1626 to 28. The results were not encouraging...... in the military field and they were disastrous as far as fiscal matters were concerned. Sweden took over the leadership of the protestant side and she took over Denmark’s place amongst the great powers of the Baltic Region. From that time onwards, Danish influence and options on the international stage gradually...... declined. Thus, Denmark of the 17th century is not to be counted amongst the great powers, but since Christian V’s accession to the throne in 1670 Denmark-Norway has developed into one of Europe’s most highly militarised states. Apart from a permanently combat ready navy, the country maintains a standing...

  8. An explicit asymptotic preserving low Froude scheme for the multilayer shallow water model with density stratification

    Science.gov (United States)

    Couderc, F.; Duran, A.; Vila, J.-P.

    2017-08-01

    We present an explicit scheme for a two-dimensional multilayer shallow water model with density stratification, for general meshes and collocated variables. The proposed strategy is based on a regularized model where the transport velocity in the advective fluxes is shifted proportionally to the pressure potential gradient. Using a similar strategy for the potential forces, we show the stability of the method in the sense of a discrete dissipation of the mechanical energy, in general multilayer and non-linear frames. These results are obtained at first-order in space and time and extended using a second-order MUSCL extension in space and a Heun's method in time. With the objective of minimizing the diffusive losses in realistic contexts, sufficient conditions are exhibited on the regularizing terms to ensure the scheme's linear stability at first and second-order in time and space. The other main result stands in the consistency with respect to the asymptotics reached at small and large time scales in low Froude regimes, which governs large-scale oceanic circulation. Additionally, robustness and well-balanced results for motionless steady states are also ensured. These stability properties tend to provide a very robust and efficient approach, easy to implement and particularly well suited for large-scale simulations. Some numerical experiments are proposed to highlight the scheme efficiency: an experiment of fast gravitational modes, a smooth surface wave propagation, an initial propagating surface water elevation jump considering a non-trivial topography, and a last experiment of slow Rossby modes simulating the displacement of a baroclinic vortex subject to the Coriolis force.

  9. Mobile augmented reality applications for heritage preservation in UNESCO world heritage sites through adopting the UTAUT model

    Science.gov (United States)

    Shang, Low Wei; Siang, Tan Gek; Zakaria, Mohd Hafiz bin; Emran, Muhammad Helmy

    2017-04-01

    Augmented reality (AR) technology has undergone enormous advancement and now AR applications can be seamlessly executed using modern-day smartphones. This study aims to develop a mobile AR application which consists of 3D AR models of historical monuments located within the UNESCO World Heritage Site in Melaka. The application allows tourists to obtain information of the monuments from the AR models, which provide an alternative way of visiting the actual monuments to prevent overcrowding effect and promote heritage preservation. Perceived Usefulness (PU), Perceived Ease of Use (PEU), Facilitating Conditions (FC), and Perceived Playfulness (PP) are proposed as the determinants of user's Behavioural Intention to Use (BI) the application. Using 50 tourists in Melaka as respondents, a pilot study has been conducted to determine user's acceptance of the AR mobile application based on the Unified Theory of Acceptance and Use of Technology (UTAUT). Cronbach's Alpha test validated the internal consistency of the measures. Multiple Linear Regression analysis suggested that the proposed determinants explained 51.2% in user's BI the application. PU was the strongest determinant followed by FC while PEU and PP were found to be insignificant.

  10. A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks.

    Science.gov (United States)

    Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

    2016-10-14

    In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network.

  11. An asymptotic preserving scheme for P1 model using classical diffusion schemes on unstructured polygonal meshes

    Directory of Open Access Journals (Sweden)

    Navaro Pierre

    2011-11-01

    Full Text Available A new scheme for discretizing the P1 model on unstructured polygonal meshes is proposed. This scheme is designed such that its limit in the diffusion regime is the MPFA-O scheme which is proved to be a consistent variant of the Breil-Maire diffusion scheme. Numerical tests compare this scheme with a derived GLACE scheme for the P1 system. Un nouveau schéma de discrétisation du modèle P1 sur maillage non structuré composé de polygones est proposé. Ce schéma est construit pour que sa limite en régime diffusion soit le schéma MPFA-O qu’on démontre être une variante consistante du schéma de diffusion de Breil-Maire. Ce schéma est comparé sur des cas tests avec un schéma dérivé du schéma GLACE pour le modèle P1.

  12. Triptolide preserves cognitive function and reduces neuropathology in a mouse model of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Shaowu Cheng

    Full Text Available Triptolide, a major bioactive ingredient of a widely used herbal medicine, has been shown to possess multiple pharmacological functions, including potential neuroprotective effects pertinent to Alzheimer's disease (AD in vitro. However, the therapeutic potential of triptolide for AD in vivo has not been thoroughly evaluated. In the present study, we investigated the impact of peripherally administered triptolide on AD-related behavior and neuropathology in APPswe/PS1ΔE9 (APP/PS1 mice, an established model of AD. Our results showed that two-month treatment with triptolide rescued cognitive function in APP/PS1 mice. Immunohistochemical analyses indicated that triptolide treatment led to a significant decrease in amyloid-β (Aβ deposition and neuroinflammation in treated mice. In contrast to previous findings in vitro, biochemical analyses showed that triptolide treatment did not significantly affect the production pathway of Aβ in vivo. Intriguingly, further analyses revealed that triptolide treatment upregulated the level of insulin-degrading enzyme, a major Aβ-degrading enzyme in the brain, indicating that triptolide treatment reduced Aβ pathology by enhancing the proteolytic degradation of Aβ. Our findings demonstrate that triptolide treatment ameliorates key behavioral and neuropathological changes found in AD, suggesting that triptolide may serve as a potential therapeutic agent for AD.

  13. Preservation in New Buildings

    Directory of Open Access Journals (Sweden)

    Christopher Kitching

    2000-06-01

    Full Text Available In the United Kingdom (as in many other countries increasing attention is being paid to the importance of each library and archive having a written preservation strategy endorsed by its governing body. So increasingly we are asking: where does „preservation“ begin and what are its top priorities? Some would say preservation begins with the definition of collecting policies to ensure that only relevant items are acquired in the first place, and therefore that no unnecessary costs are incurred on the long-term care of unwanted and unconsulted items. Others might argue that the first priority must be the careful appraisal of existing holdings to determine their preservation and conservation requirements and to prioritise their treatment. Or should preservation begin with damage-limitation: restricting the physical handling of books and documents, on the one hand by providing whenever possible surrogate copies in digital formats or microform, and on the other hand by offering at least basic protection through appropriate boxing and packaging? This, surely, goes hand-in-hand with the education of staff and readers about the importance of treating rare or unique materials with proper respect.

  14. User Experience and Heritage Preservation

    Science.gov (United States)

    Orfield, Steven J.; Chapman, J. Wesley; Davis, Nathan

    2011-01-01

    In considering the heritage preservation of higher education campus buildings, much of the attention gravitates toward issues of selection, cost, accuracy, and value, but the model for most preservation projects does not have a clear method of achieving the best solutions for meeting these targets. Instead, it simply relies on the design team and…

  15. User Experience and Heritage Preservation

    Science.gov (United States)

    Orfield, Steven J.; Chapman, J. Wesley; Davis, Nathan

    2011-01-01

    In considering the heritage preservation of higher education campus buildings, much of the attention gravitates toward issues of selection, cost, accuracy, and value, but the model for most preservation projects does not have a clear method of achieving the best solutions for meeting these targets. Instead, it simply relies on the design team and…

  16. Thermodynamic investigation of the interaction between cyclodextrins and preservatives—application and verification in a mathematical model to determine the needed preservative surplus in aqueous cyclodextrin formulations

    DEFF Research Database (Denmark)

    Holm, Rene; Olesen, Niels Erik; Alexandersen, Signe D.;

    2016-01-01

    determined by isothermal titration calorimetry. Based upon this knowledge mathematical models were constructed to account for the equilibrium systems and to calculate the required concentration of the preservations, which was evaluated experimentally based upon the USP/Ph. Eur./JP monograph. The mathematical...

  17. Multiple endpoint analysis of BAC-preserved and unpreserved antiallergic eye drops on a 3D-reconstituted corneal epithelial model

    OpenAIRE

    Pauly, A.; Brasnu, E.; Riancho, L.; Brignole-Baudouin, F.; Baudouin, C

    2011-01-01

    Purpose To compare the effects of benzalkonium chloride (BAC)-preserved and unpreserved antiallergic eye drops on the human 3D-reconstituted corneal epithelial model (3D-HCE). Methods 3D-HCE were treated for 24 h followed or not by a 24 h post-incubation recovery period (24 h+24 h) with phosphate-buffered saline (PBS), 0.01% BAC, unpreserved formulations of ketotifen, N Acetyl-Aspartyl Glutamic Acid (NAAGA), cromoglycate, or BAC-preserved commercial formulations of ketotifen, olopatadine, epi...

  18. The Importance of Precise Digital Elevation Models (DEM) in Modelling Floods

    Science.gov (United States)

    Demir, Gokben; Akyurek, Zuhal

    2016-04-01

    Digital elevation Models (DEM) are important inputs for topography for the accurate modelling of floodplain hydrodynamics. Floodplains have a key role as natural retarding pools which attenuate flood waves and suppress flood peaks. GPS, LIDAR and bathymetric surveys are well known surveying methods to acquire topographic data. It is not only time consuming and expensive to obtain topographic data through surveying but also sometimes impossible for remote areas. In this study it is aimed to present the importance of accurate modelling of topography for flood modelling. The flood modelling for Samsun-Terme in Blacksea region of Turkey is done. One of the DEM is obtained from the point observations retrieved from 1/5000 scaled orthophotos and 1/1000 scaled point elevation data from field surveys at x-sections. The river banks are corrected by using the orthophotos and elevation values. This DEM is named as scaled DEM. The other DEM is obtained from bathymetric surveys. 296 538 number of points and the left/right bank slopes were used to construct the DEM having 1 m spatial resolution and this DEM is named as base DEM. Two DEMs were compared by using 27 x-sections. The maximum difference at thalweg of the river bed is 2m and the minimum difference is 20 cm between two DEMs. The channel conveyance capacity in base DEM is larger than the one in scaled DEM and floodplain is modelled in detail in base DEM. MIKE21 with flexible grid is used in 2- dimensional shallow water flow modelling. The model by using two DEMs were calibrated for a flood event (July 9, 2012). The roughness is considered as the calibration parameter. From comparison of input hydrograph at the upstream of the river and output hydrograph at the downstream of the river, the attenuation is obtained as 91% and 84% for the base DEM and scaled DEM, respectively. The time lag in hydrographs does not show any difference for two DEMs and it is obtained as 3 hours. Maximum flood extents differ for the two DEMs

  19. A coupled model between mechanical deformation and chemical diffusion: An explanation for the preservation of chemical zonation in plagioclase at high temperatures

    Science.gov (United States)

    Zhong, Xin; Vrijmoed, Johannes; Moulas, Evangelos; Tajcmanová, Lucie

    2016-04-01

    Compositional zoning in metamorphic minerals have been generally recognized as an important geological feature to decipher the metamorphic history of rocks. The observed chemical zoning of, e.g. garnet, is commonly interpreted as disequilibrium between the fractionated inner core and the surrounding matrix. However, chemically zoned minerals were also observed in high grade rocks (T>800 degree C) where the duration of metamorphic processes was independently dated to take several Ma. This implies that temperature may not be the only factor that controls diffusion timescales, and grain scale pressure variation was proposed to be a complementary factor that may significantly contribute to the formation and preservation of chemical zoning in high temperature metamorphic minerals [Tajcmanová 2013, 2015]. Here, a coupled model is developed to simulate viscous deformation and chemical diffusion. The numerical approach considers the conservation of mass, momentum, and a constitutive relation developed from equilibrium thermodynamics. A compressible viscoelastic rheology is applied, which associates the volumetric change triggered by deformation and diffusion to a change of pressure. The numerical model is applied to the chemically zoned plagioclase rim described by [Tajcmanová 2014]. The diffusion process operating during the plagioclase rim formation can lead to a development of a pressure gradient. Such a pressure gradient, if maintained during ongoing viscous relaxation, can lead to the preservation of the observed chemical zonation in minerals. An important dimensionless number, the Deborah number, is defined as the ratio between the Maxwell viscoelastic relaxation time and the characteristic diffusion time. It characterizes the relative influence between the maintenance of grain scale pressure variation and chemical diffusion. Two extreme regimes are shown: the mechanically-controlled regime (high Deborah number) and diffusion-controlled regime (low Deborah number

  20. Intranasal Delivery of A Novel Amnion Cell Secretome Prevents Neuronal Damage and Preserves Function In A Mouse Multiple Sclerosis Model

    Science.gov (United States)

    Khan, Reas S.; Dine, Kimberly; Bauman, Bailey; Lorentsen, Michael; Lin, Lisa; Brown, Helayna; Hanson, Leah R.; Svitak, Aleta L.; Wessel, Howard; Brown, Larry; Shindler, Kenneth S.

    2017-01-01

    The ability of a novel intranasally delivered amnion cell derived biologic to suppress inflammation, prevent neuronal damage and preserve neurologic function in the experimental autoimmune encephalomyelitis animal model of multiple sclerosis was assessed. Currently, there are no existing optic nerve treatment methods for disease or trauma that result in permanent vision loss. Demyelinating optic nerve inflammation, termed optic neuritis, induces permanent visual dysfunction due to retinal ganglion cell damage in multiple sclerosis and experimental autoimmune encephalomyelitis. ST266, the biological secretome of Amnion-derived Multipotent Progenitor cells, contains multiple anti-inflammatory cytokines and growth factors. Intranasally administered ST266 accumulated in rodent eyes and optic nerves, attenuated visual dysfunction, and prevented retinal ganglion cell loss in experimental optic neuritis, with reduced inflammation and demyelination. Additionally, ST266 reduced retinal ganglion cell death in vitro. Neuroprotective effects involved oxidative stress reduction, SIRT1-mediated mitochondrial function promotion, and pAKT signaling. Intranasal delivery of neuroprotective ST266 is a potential novel, noninvasive therapeutic modality for the eyes, optic nerves and brain. The unique combination of biologic molecules in ST266 provides an innovative approach with broad implications for suppressing inflammation in autoimmune diseases, and for preventing neuronal damage in acute neuronal injury and chronic neurodegenerative diseases such as multiple sclerosis. PMID:28139754

  1. PDF-ECG in clinical practice: A model for long-term preservation of digital 12-lead ECG data.

    Science.gov (United States)

    Sassi, Roberto; Bond, Raymond R; Cairns, Andrew; Finlay, Dewar D; Guldenring, Daniel; Libretti, Guido; Isola, Lamberto; Vaglio, Martino; Poeta, Roberto; Campana, Marco; Cuccia, Claudio; Badilini, Fabio

    2017-08-12

    In clinical practice, data archiving of resting 12-lead electrocardiograms (ECGs) is mainly achieved by storing a PDF report in the hospital electronic health record (EHR). When available, digital ECG source data (raw samples) are only retained within the ECG management system. The widespread availability of the ECG source data would undoubtedly permit successive analysis and facilitate longitudinal studies, with both scientific and diagnostic benefits. PDF-ECG is a hybrid archival format which allows to store in the same file both the standard graphical report of an ECG together with its source ECG data (waveforms). Using PDF-ECG as a model to address the challenge of ECG data portability, long-term archiving and documentation, a real-world proof-of-concept test was conducted in a northern Italy hospital. A set of volunteers undertook a basic ECG using routine hospital equipment and the source data captured. Using dedicated web services, PDF-ECG documents were then generated and seamlessly uploaded in the hospital EHR, replacing the standard PDF reports automatically generated at the time of acquisition. Finally, the PDF-ECG files could be successfully retrieved and re-analyzed. Adding PDF-ECG to an existing EHR had a minimal impact on the hospital's workflow, while preserving the ECG digital data. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Relaxin as an additional protective substance in preserving and reperfusion solution for liver transplantation, shown in a model of isolated perfused rat liver.

    Science.gov (United States)

    Boehnert, Markus U; Hilbig, Heidegard; Armbruster, Franz P

    2005-05-01

    Reperfusion injury is a problem in organ transplantation. Relaxin causes vessel dilation and inhibition of platelet and mast cell activation. The study investigates the protective effect of relaxin on liver tissue against cell damage during organ preservation and reperfusion. Liver transplantation was simulated in a model of isolated perfused rat liver. Relaxin was applicated during reperfusion and/or preservation. To quantify cell damage, we examined the perfusate for malonyldialdehyde (MDA) and myeloperoxidase activity (MPO), and liver tissue underwent immunohistochemical study. Relaxin as an additional substance in preserving/reperfusion solution decreases MPO and MDA levels in the perfusate and immunohistochemical study. Relaxin seems to have a protective effect against cell damage in ischemia and reperfusion injury.

  3. A standardized model of brain death, donor treatment, and lung transplantation for studies on organ preservation and reconditioning.

    Science.gov (United States)

    Valenza, Franco; Coppola, Silvia; Froio, Sara; Ruggeri, Giulia Maria; Fumagalli, Jacopo; Villa, Alessandro Maria; Rosso, Lorenzo; Mendogni, Paolo; Conte, Grazia; Lonati, Caterina; Carlin, Andrea; Leonardi, Patrizia; Gatti, Stefano; Stocchetti, Nino; Gattinoni, Luciano

    2014-12-01

    We set a model of brain death, donor management, and lung transplantation for studies on lung preservation and reconditioning before transplantation. Ten pigs (39.7 ± 5.9 Kg) were investigated. Five animals underwent brain death and were treated as organ donors; the lungs were then procured and cold stored (Ischemia). Five recipients underwent left lung transplantation and post-reperfusion follow-up (Graft). Cardiorespiratory and metabolic parameters were collected. Lung gene expression of cytokines (tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interferon gamma (IFNγ), high mobility group box-1 (HMGB-1)), chemokines (chemokine CC motif ligand-2 (CCL2-MCP-1), chemokine CXC motif ligand-10 (CXCL-10), interleukin-8 (IL-8)), and endothelial activation markers (endothelin-1 (EDN-1), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), selectin-E (SELE)) was assessed by real-time polymerase chain reaction (PCR). Tachycardia and hypertension occurred during brain death induction; cardiac output rose, systemic vascular resistance dropped (P Six hours after controlled reperfusion, PaO2 was 192 ± 23 mmHg (PEEP 8.7 ± 1.5 cmH2O, FiO2 40%), W/D was 5.6 ± 0.4, and EVLW was 366 ± 117 mL. Levels of IL-8 rose at the end of donor management (BD, P model resembling the entire process of organ donation that may be used as a platform to test in vivo and ex vivo strategies of donor lung optimization before transplantation.

  4. Estimating the economic value of national parks with count data models using on-site, secondary data: the case of the great sand dunes national park and preserve.

    Science.gov (United States)

    Heberling, Matthew T; Templeton, Joshua J

    2009-04-01

    We estimate an individual travel cost model for Great Sand Dunes National Park and Preserve (GSD) in Colorado using on-site, secondary data. The purpose of the on-site survey was to help the National Park Service better understand the visitors of GSD; it was not intended for a travel cost model. Variables such as travel cost and income were estimated based on respondents' Zip Codes. Following approaches found in the literature, a negative binomial model corrected for truncation and endogenous stratification fit the data the best. We estimate a recreational benefit of U.S. $89/visitor/year or U.S. $54/visitor/24-h recreational day (in 2002 U.S. $). Based on the approach presented here, there are other data sets for national parks, preserves, and battlefields where travel cost models could be estimated and used to support National Park Service management decisions.

  5. Modeling lactose hydrolysis for efficiency and selectivity: Toward the preservation of sialyloligosaccharides in bovine colostrum whey permeate.

    Science.gov (United States)

    de Moura Bell, Juliana M L N; Aquino, Leticia F M C; Liu, Yan; Cohen, Joshua L; Lee, Hyeyoung; de Melo Silva, Vitor L; Rodrigues, Maria I; Barile, Daniela

    2016-08-01

    Enzymatic hydrolysis of lactose has been shown to improve the efficiency and selectivity of membrane-based separations toward the recovery of bioactive oligosaccharides. Achieving maximum lactose hydrolysis requires intrinsic process optimization for each specific substrate, but the effects of those processing conditions on the target oligosaccharides are not well understood. Response surface methodology was used to investigate the effects of pH (3.25-8.25), temperature (35-55°C), reaction time (6 to 58 min), and amount of enzyme (0.05-0.25%) on the efficiency of lactose hydrolysis by β-galactosidase and on the preservation of biologically important sialyloligosaccharides (3'-siallylactose, 6'-siallylactose, and 6'-sialyl-N-acetyllactosamine) naturally present in bovine colostrum whey permeate. A central composite rotatable design was used. In general, β-galactosidase activity was favored at pH values ranging from 3.25 to 5.75, with other operational parameters having a less pronounced effect. A pH of 4.5 allowed for the use of a shorter reaction time (19 min), lower temperature (40°C), and reduced amount of enzyme (0.1%), but complete hydrolysis at a higher pH (5.75) required greater values for these operational parameters. The total amount of sialyloligosaccharides was not significantly altered by the reaction parameters evaluated, suggesting specificity of β-galactosidase from Aspergillus oryzae toward lactose as well as the stability of the oligosaccharides at pH, temperature, and reaction time evaluated.

  6. Contact dermatitis caused by preservatives.

    Science.gov (United States)

    Yim, Elizabeth; Baquerizo Nole, Katherine L; Tosti, Antonella

    2014-01-01

    Preservatives are biocidal chemicals added to food, cosmetics, and industrial products to prevent the growth of microorganisms. They are usually nontoxic and inexpensive and have a long shelf life. Unfortunately, they commonly cause contact dermatitis. This article reviews the most important classes of preservatives physicians are most likely to encounter in their daily practice, specifically isothiazolinones, formaldehyde and formaldehyde-releasers, iodopropynyl butylcarbamate, methyldibromoglutaronitrile, and parabens. For each preservative mentioned, the prevalence of sensitization, clinical presentation of contact dermatitis, patch testing concentrations, cross reactions, and related legislation will be discussed. Mandatory labeling of preservatives is required in some countries, but not required in others. Until policies are made, physicians and patients must be proactive in identifying potential sensitizers and removing their use. We hope that this article will serve as a guide for policy makers in creating legislation and future regulations on the use and concentration of certain preservatives in cosmetics and industrial products.

  7. A holistic approach to bit preservation

    DEFF Research Database (Denmark)

    Zierau, Eld

    2012-01-01

    Purpose: The purpose of this paper is to point out the importance of taking a holistic approach to bit preservation when setting out to find an optimal bit preservation solution for specific digital materials. In the last decade there has been an increasing awareness that bit preservation, which ...

  8. Educating for preserving biodiversity

    Directory of Open Access Journals (Sweden)

    Méndez, I. E.

    2014-01-01

    Full Text Available The notion of “culture of diversity” is presented in a new dimension. “That of educating for preserving biodiversity” is advanced together with its main challenges. The need of educating the masses for preserving biodiversity is perhaps the most outstanding to be faced, particularly if pedagogic requirements and the diversity of population is to be met. Likewise, it should help to put individuals in contact with the many elements conforming biodiversity and lead them to recognize its value ethically and esthetically. The research presents the framework for designing educating programs enhancing the genetic level, the ecosystem and the qualitative dimension and including materials and energy flood and its meaning for the homeostasis and autopoiesis of the system, together with its interactions with other components for achieving an equilibrium and stability. The importance of the natural evolution tendency is highlighted.

  9. Reflections on trends in the identification and preservation of digital ...

    African Journals Online (AJOL)

    Lori Ashley

    Digital Preservation Capability Maturity Model. Workshop ... of thought and activity in the evolution of the management and preservation .... Information Technologies: The Impact of Information ..... preservation readiness capability into business.

  10. Ecological niche modeling in Maxent: the importance of model complexity and the performance of model selection criteria.

    Science.gov (United States)

    Warren, Dan L; Seifert, Stephanie N

    2011-03-01

    Maxent, one of the most commonly used methods for inferring species distributions and environmental tolerances from occurrence data, allows users to fit models of arbitrary complexity. Model complexity is typically constrained via a process known as L1 regularization, but at present little guidance is available for setting the appropriate level of regularization, and the effects of inappropriately complex or simple models are largely unknown. In this study, we demonstrate the use of information criterion approaches to setting regularization in Maxent, and we compare models selected using information criteria to models selected using other criteria that are common in the literature. We evaluate model performance using occurrence data generated from a known "true" initial Maxent model, using several different metrics for model quality and transferability. We demonstrate that models that are inappropriately complex or inappropriately simple show reduced ability to infer habitat quality, reduced ability to infer the relative importance of variables in constraining species' distributions, and reduced transferability to other time periods. We also demonstrate that information criteria may offer significant advantages over the methods commonly used in the literature.

  11. Effort- and flow-constraint reduction methods for structure preserving model reduction of port-Hamiltonian systems

    NARCIS (Netherlands)

    Polyuga, Rostyslav V.; Schaft, Arjan J. van der

    2012-01-01

    The geometric formulation of general port-Hamiltonian systems is used in order to obtain two structure preserving reduction methods. The main idea is to construct a reduced-order Dirac structure corresponding to zero power flow in some of the energy-storage ports. This can be performed in two canoni

  12. The importance of information goods abstraction levels for information commerce process models

    NARCIS (Netherlands)

    Wijnhoven, Fons

    2002-01-01

    A process model, in the context of e-commerce, is an organized set of activities for the creation, (re-)production, trade and delivery of goods. Electronic commerce studies have created important process models for the trade of physical goods via Internet. These models are not easily suitable for th

  13. A new process sensitivity index to identify important system processes under process model and parametric uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Heng [Pacific Northwest National Laboratory, Richland Washington USA; Ye, Ming [Department of Scientific Computing, Florida State University, Tallahassee Florida USA; Walker, Anthony P. [Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Chen, Xingyuan [Pacific Northwest National Laboratory, Richland Washington USA

    2017-04-01

    Hydrological models are always composed of multiple components that represent processes key to intended model applications. When a process can be simulated by multiple conceptual-mathematical models (process models), model uncertainty in representing the process arises. While global sensitivity analysis methods have been widely used for identifying important processes in hydrologic modeling, the existing methods consider only parametric uncertainty but ignore the model uncertainty for process representation. To address this problem, this study develops a new method to probe multimodel process sensitivity by integrating the model averaging methods into the framework of variance-based global sensitivity analysis, given that the model averaging methods quantify both parametric and model uncertainty. A new process sensitivity index is derived as a metric of relative process importance, and the index includes variance in model outputs caused by uncertainty in both process models and model parameters. For demonstration, the new index is used to evaluate the processes of recharge and geology in a synthetic study of groundwater reactive transport modeling. The recharge process is simulated by two models that converting precipitation to recharge, and the geology process is also simulated by two models of different parameterizations of hydraulic conductivity; each process model has its own random parameters. The new process sensitivity index is mathematically general, and can be applied to a wide range of problems in hydrology and beyond.

  14. Preservation versus non-preservation of mitral valve apparatus during mitral valve replacement: a meta-analysis of 3835 patients

    Science.gov (United States)

    Sá, Michel Pompeu Barros de Oliveira; Ferraz, Paulo Ernando; Escobar, Rodrigo Renda; Martins, Wendell Santos; de Araújo e Sá, Frederico Browne Correia; Lustosa, Pablo César; Vasconcelos, Frederico Pires; Lima, Ricardo Carvalho

    2012-01-01

    Resection of the chordopapillary apparatus during mitral valve replacement has been associated with a negative impact on survival. Mitral valve replacement with the preservation of the mitral valve apparatus has been associated with better outcomes, but surgeons remain refractory to its use. To determine if there is any real difference in preservation vs non-preservation of mitral valve apparatus during mitral valve replacement in terms of outcomes, we performed a systematic review and meta-analysis using MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar and reference lists of relevant articles to search for clinical studies that compared outcomes (30-day mortality, postoperative low cardiac output syndrome or 5-year mortality) between preservation vs non-preservation during mitral valve replacement from 1966 to 2011. The principal summary measures were odds ratios (ORs) with 95% confidence interval and P-values (that will be considered statistically significant when <0.05). The ORs were combined across studies using a weighted DerSimonian–Laird random-effects model. The meta-analysis was completed using the software Comprehensive Meta-Analysis version 2 (Biostat Inc., Englewood, NJ, USA). Twenty studies (3 randomized and 17 non-randomized) were identified and included a total of 3835 patients (1918 for mitral valve replacement preservation and 1917 for mitral valve replacement non-preservation). There was significant difference between mitral valve replacement preservation and mitral valve replacement non-preservation groups in the risk of 30-day mortality (OR 0.418, P <0.001), postoperative low cardiac output syndrome (OR 0.299, P <0.001) or 5-year mortality (OR 0.380, P <0.001). No publication bias or important heterogeneity of effects on any outcome was observed. In conclusion, we found evidence that argues in favour of the preservation of mitral valve apparatus during mitral valve replacement. PMID:23027596

  15. ASYMMETRIC PRICE TRANSMISSION MODELING: THE IMPORTANCE OF MODEL COMPLEXITY AND THE PERFORMANCE OF THE SELECTION CRITERIA

    Directory of Open Access Journals (Sweden)

    Henry de-Graft Acquah

    2013-01-01

    Full Text Available Information Criteria provides an attractive basis for selecting the best model from a set of competing asymmetric price transmission models or theories. However, little is understood about the sensitivity of the model selection methods to model complexity. This study therefore fits competing asymmetric price transmission models that differ in complexity to simulated data and evaluates the ability of the model selection methods to recover the true model. The results of Monte Carlo experimentation suggest that in general BIC, CAIC and DIC were superior to AIC when the true data generating process was the standard error correction model, whereas AIC was more successful when the true model was the complex error correction model. It is also shown that the model selection methods performed better in large samples for a complex asymmetric data generating process than with a standard asymmetric data generating process. Except for complex models, AIC's performance did not make substantial gains in recovery rates as sample size increased. The research findings demonstrate the influence of model complexity in asymmetric price transmission model comparison and selection.

  16. Active preservation - otherwise no archives

    Energy Technology Data Exchange (ETDEWEB)

    Norberg, E. [National Swedish Archives, Stockholm (Sweden)

    1996-12-01

    The role and history of national and regional archives in Sweden is discussed. It is noted that large portions of our cultural heritage can not be set aside for long-term preservation due to several facts: Some events are never documented, Important records are never set aside, Important information is stored on media that are not suitable for long-term preservation, Information can not be accessed due to inadequate search aids, Eliminations are made due to lack of space. Strategies for an action plan to save valuable material are briefly outlined, and the importance of international cooperation is stressed.

  17. Demand Estimation for US Apple Juice Imports: A Restricted Source Differentiated AIDS Model

    OpenAIRE

    Mekonnen, Dawit Kelemework; Fonsah, Esendugue Greg

    2011-01-01

    Although this paper focuses on apple juice, a restricted version of source differentiated Almost Ideal Demand System (RSDAIDS) was used to examine U.S. import demand for fresh apple, apple juice and other processed apple. Apple imports were differentiated by type and source of origin and the RSDAIDS model was estimated after imposing the general demand restrictions of adding-up, homogeneity and slutsky symmetry. Seasonality and trend variables were also included on the model. The estimation r...

  18. Modeling the interaction of electric current and tissue: importance of accounting for time varying electric properties.

    Science.gov (United States)

    Evans, Daniel J; Manwaring, Mark L

    2007-01-01

    Time varying computer models of the interaction of electric current and tissue are very valuable in helping to understand the complexity of the human body and biological tissue. The electrical properties of tissue, permittivity and conductivity, are vital to accurately modeling the interaction of the human tissue with electric current. Past models have represented the electric properties of the tissue as constant or temperature dependent. This paper presents time dependent electric properties that change as a result of tissue damage, temperature, blood flow, blood vessels, and tissue property. Six models are compared to emphasize the importance of accounting for these different tissue properties in the computer model. In particular, incorporating the time varying nature of the electric properties of human tissue into the model leads to a significant increase in tissue damage. An important feature of the model is the feedback loop created between the electric properties, tissue damage, and temperature.

  19. Catfish Preservation using Porphyra Yezoensis Composites Preservatives

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Qian

    2013-09-01

    Full Text Available This study aims to preserve fresh catfish meat by using Porphyra Yezoensis extract, chitosan and lactic acid Nisin. The composite preservative obtained by sensory evaluation can effectively maintain the color, odor and texture of fresh catfish meat, as well as inhibit bacterial growth. Results show that treatment using a preservative solution (Porphyra Yezoensis extract 10%, Nisin 0.2% and chitosan 15% extended the shelf life of the fresh catfish meat from 12 h to 24 h when stored at room temperature and from 6 d to 9 d when stored at 4°C. These results provide a practical method of preserving fresh catfish meat.

  20. Long-term preservation of cones and improvement in visual function following gene therapy in a mouse model of leber congenital amaurosis caused by guanylate cyclase-1 deficiency.

    Science.gov (United States)

    Mihelec, Marija; Pearson, Rachael A; Robbie, Scott J; Buch, Prateek K; Azam, Selina A; Bainbridge, James W B; Smith, Alexander J; Ali, Robin R

    2011-10-01

    Leber congenital amaurosis (LCA) is a severe retinal dystrophy manifesting from early infancy as poor vision or blindness. Loss-of-function mutations in GUCY2D cause LCA1 and are one of the most common causes of LCA, accounting for 20% of all cases. Human GUCY2D and mouse Gucy2e genes encode guanylate cyclase-1 (GC1), which is responsible for restoring the dark state in photoreceptors after light exposure. The Gucy2e(-/-) mouse shows partially diminished rod function, but an absence of cone function before degeneration. Although the cones appear morphologically normal, they exhibit mislocalization of proteins involved in phototransduction. In this study we tested the efficacy of an rAAV2/8 vector containing the human rhodopsin kinase promoter and the human GUCY2D gene. Following subretinal delivery of the vector in Gucy2e(-/-) mice, GC1 protein was detected in the rod and cone outer segments, and in transduced areas of retina cone transducin was appropriately localized to cone outer segments. Moreover, we observed a dose-dependent restoration of rod and cone function and an improvement in visual behavior of the treated mice. Most importantly, cone preservation was observed in transduced areas up to 6 months post injection. To date, this is the most effective rescue of the Gucy2e(-/-) mouse model of LCA and we propose that a vector, similar to the one used in this study, could be suitable for use in a clinical trial of gene therapy for LCA1.

  1. Explaining German imports of olive oil: evidence from a gravity model

    OpenAIRE

    2008-01-01

    In this study the case of olive oil imports of Germany is examined since olive oil is a traditional Mediterranean commodity and Germany is the biggest importer in the EU. A gravity model has been employed so as to analyse those factors that explain the German imports of olive oil that were identified in a preceding analysis of the German olive oil supply chain. The results of two random-effects models corrected for serial correlation and heteroskedasticity suggest that being a Mediterranean P...

  2. The Importance and Weaknesses of the Productivist Industrial Model of Knowledge Production

    Science.gov (United States)

    Persson, Roland S.

    2010-01-01

    To view contemporary Science as an industry is a very apt and timely stance. Ghassib's (2010) historical analysis of knowledge production, which he terms "A Productivist Industrial Model of Knowledge Production," is an interesting one. It is important, however, to observe that the outline of this model is based entirely on the production of…

  3. Scientist Role Models in the Classroom: How Important Is Gender Matching?

    Science.gov (United States)

    Conner, Laura D. Carsten; Danielson, Jennifer

    2016-01-01

    Gender-matched role models are often proposed as a mechanism to increase identification with science among girls, with the ultimate aim of broadening participation in science. While there is a great deal of evidence suggesting that role models can be effective, there is mixed support in the literature for the importance of gender matching. We used…

  4. The common fate model for dyadic data: variations of a theoretically important but underutilized model.

    Science.gov (United States)

    Ledermann, Thomas; Kenny, David A

    2012-02-01

    Studying dyads, very often there is a theoretical construct that has an effect on both members, such as relationship harmony or shared environment. To model such influences, the common fate model (CFM) is often the most appropriate approach. In this article, we address conceptual and statistical issues in the use of the standard CFM and present a series of variations, all of which are estimated by structural equation modeling (SEM). For indistinguishable dyad members (e.g., gay couples), we describe the use of a multilevel SEM method. Throughout the paper, we draw connections to the actor-partner interdependence model (APIM). We also discuss the analysis of hybrid models that combines both the CFM and the APIM. The models are illustrated using data from heterosexual couples.

  5. The importance of topographically corrected null models for analyzing ecological point processes.

    Science.gov (United States)

    McDowall, Philip; Lynch, Heather J

    2017-07-01

    Analyses of point process patterns and related techniques (e.g., MaxEnt) make use of the expected number of occurrences per unit area and second-order statistics based on the distance between occurrences. Ecologists working with point process data often assume that points exist on a two-dimensional x-y plane or within a three-dimensional volume, when in fact many observed point patterns are generated on a two-dimensional surface existing within three-dimensional space. For many surfaces, however, such as the topography of landscapes, the projection from the surface to the x-y plane preserves neither area nor distance. As such, when these point patterns are implicitly projected to and analyzed in the x-y plane, our expectations of the point pattern's statistical properties may not be met. When used in hypothesis testing, we find that the failure to account for the topography of the generating surface may bias statistical tests that incorrectly identify clustering and, furthermore, may bias coefficients in inhomogeneous point process models that incorporate slope as a covariate. We demonstrate the circumstances under which this bias is significant, and present simple methods that allow point processes to be simulated with corrections for topography. These point patterns can then be used to generate "topographically corrected" null models against which observed point processes can be compared. © 2017 by the Ecological Society of America.

  6. Oxygen absorbers in food preservation: a review

    OpenAIRE

    Cichello, Simon Angelo

    2014-01-01

    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen imperme...

  7. Importance of demand modelling in network water quality models: a review

    Directory of Open Access Journals (Sweden)

    J. C. van Dijk

    2008-09-01

    Full Text Available Today, there is a growing interest in network water quality modelling. The water quality issues of interest relate to both dissolved and particulate substances. For dissolved substances the main interest is in residual chlorine and (microbiological contaminant propagation; for particulate substances it is in sediment leading to discolouration. There is a strong influence of flows and velocities on transport, mixing, production and decay of these substances in the network. This imposes a different approach to demand modelling which is reviewed in this article.

    For the large diameter lines that comprise the transport portion of a typical municipal pipe system, a skeletonised network model with a top-down approach of demand pattern allocation, a hydraulic time step of 1 h, and a pure advection-reaction water quality model will usually suffice. For the smaller diameter lines that comprise the distribution portion of a municipal pipe system, an all-pipes network model with a bottom-up approach of demand pattern allocation, a hydraulic time step of 1 min or less, and a water quality model that considers dispersion and transients may be needed.

    Demand models that provide stochastic residential demands per individual home and on a one-second time scale are available. A stochastic demands based network water quality model needs to be developed and validated with field measurements. Such a model will be probabilistic in nature and will offer a new perspective for assessing water quality in the drinking water distribution system.

  8. Cross-entropy optimisation of importance sampling parameters for statistical model checking

    CERN Document Server

    Jégourel, Cyrille; Sedwards, Sean

    2012-01-01

    Statistical model checking avoids the exponential growth of states associated with probabilistic model checking by estimating properties from multiple executions of a system and by giving results within confidence bounds. Rare properties are often very important but pose a particular challenge for simulation-based approaches, hence a key objective under these circumstances is to reduce the number and length of simulations necessary to produce a given level of confidence. Importance sampling is a well-established technique that achieves this, however to maintain the advantages of statistical model checking it is necessary to find good importance sampling distributions without considering the entire state space. Motivated by the above, we present a simple algorithm that uses the notion of cross-entropy to find the optimal parameters for an importance sampling distribution. In contrast to previous work, our algorithm uses a low dimensional vector of parameters to define this distribution and thus avoids the ofte...

  9. Simulation modeling to derive the value-of-information for risky animal disease-import decisions.

    Science.gov (United States)

    Disney, W Terry; Peters, Mark A

    2003-11-12

    Simulation modeling can be used in aiding decision-makers in deciding when to invest in additional research and when the risky animal disease-import decision should go forward. Simulation modeling to evaluate value-of-information (VOI) techniques provides a robust, objective and transparent framework for assisting decision-makers in making risky animal and animal product decisions. In this analysis, the hypothetical risk from poultry disease in chicken-meat imports was modeled. Economic criteria were used to quantify alternative confidence-increasing decisions regarding potential import testing and additional research requirements. In our hypothetical example, additional information about poultry disease in the exporting country (either by requiring additional export-flock surveillance that results in no sign of disease, or by conducting additional research into lack of disease transmittal through chicken-meat ingestion) captured >75% of the value-of-information attainable regarding the chicken-meat-import decision.

  10. The importance of the reference populations for coherent mortality forecasting models

    DEFF Research Database (Denmark)

    Kjærgaard, Søren; Canudas-Romo, Vladimir; Vaupel, James W.

    -population mortality models aiming to find the optimal of the set of countries to use as reference population and analyse the importance of the selection of countries. The two multi-population mortality models used are the Li-Lee model and the Double-Gap life expectancy forecasting model. The reference populations...... is calculated taking into account all the possible combinations of a set of 20 industrialized countries. The different reference populations possibilities are compared by their forecast performance. The results show that the selection of countries for multi-population mortality models has a significant effect...

  11. Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution

    DEFF Research Database (Denmark)

    Kiil, Søren; Johnsson, Jan Erik; Dam-Johansen, Kim

    1999-01-01

    In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools....... In this work, a critical examination of the models was conducted. The survey revealed that the models rely on the use of adjustable parameters in order to match experimental data. To investigate this, a simple particle model was set up. Model predictions were compared to experi-mental data for three different...

  12. ARIMA MODEL BUILDING AND FORECASTING ON IMPORTS AND EXPORTS OF PAKISTAN

    Directory of Open Access Journals (Sweden)

    Ahmad Farooqi

    2014-08-01

    Full Text Available From the day one, mankind has always been interested in to the future. As the civilization advanced with growing sophistication in all phases of life, the need to look in to the future also grew with it. Today every government, public private organizations, as well as an individual would like to predict and plan for the future. In order to attain a better growth in the economy of a country, modeling and forecasting is the most important tool now a day, this can be done by one of the statistical technique called a Time series analysis. In this paper we tried to build a time series model called ARIMA (Auto Regressive Integrated Moving Average model with particular reference of Box and Jenkins approach on annually total Imports and Exports of Pakistan from the year 1947 to the year 2013 with useful statistical software R. Validity of the fitted model is tested using standard statistical techniques. The fitted model is then use to forecast some future values of Imports and export of Pakistan. It is found that an ARIMA (2, 2, 2 and ARIMA (1, 2, 2 model looks suitable to forecast the annual Imports and Exports of Pakistan respectively. We also found an increasing trend both in case of Imports and Exports during this study.

  13. Importance of demand modelling in network water quality models: a review

    Directory of Open Access Journals (Sweden)

    J. C. van Dijk

    2008-01-01

    Full Text Available Today, there is a growing interest in network water quality modelling. The water quality issues of interest relate to both dissolved and particulate substances, with the main interest in residual chlorine and (microbiological contaminant propagation, respectively in sediment leading to discolouration. There is a strong influence of flows and velocities on transport, mixing, production and decay of these substances in the network. This imposes a different approach to demand modelling which is reviewed in this article.

    For transport systems the current hydraulic models suffice; for the more detailed distribution system a network water quality model is needed that is based on short time scale demands that considers the effect of dispersion and transients. Demand models that provide stochastic residential demands per individual home and on a one-second time scale are available. A stochastic demands based network water quality model needs to be developed and validated with field measurements. Such a model will be probabilistic in nature and will offer a new perspective for assessing water quality in the DWDS.

  14. Colicin import into E. coli cells: a model system for insights into the import mechanisms of bacteriocins.

    Science.gov (United States)

    Kim, Young Chan; Tarr, Alexander W; Penfold, Christopher N

    2014-08-01

    Bacteriocins are a diverse group of ribosomally synthesized protein antibiotics produced by most bacteria. They range from small lanthipeptides produced by lactic acid bacteria to much larger multi domain proteins of Gram negative bacteria such as the colicins from Escherichia coli. For activity bacteriocins must be released from the producing cell and then bind to the surface of a sensitive cell to instigate the import process leading to cell death. For over 50years, colicins have provided a working platform for elucidating the structure/function studies of bacteriocin import and modes of action. An understanding of the processes that contribute to the delivery of a colicin molecule across two lipid membranes of the cell envelope has advanced our knowledge of protein-protein interactions (PPI), protein-lipid interactions and the role of order-disorder transitions of protein domains pertinent to protein transport. In this review, we provide an overview of the arrangement of genes that controls the synthesis and release of the mature protein. We examine the uptake processes of colicins from initial binding and sequestration of binding partners to crossing of the outer membrane, and then discuss the translocation of colicins through the cell periplasm and across the inner membrane to their cytotoxic site of action. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.

  15. The importance of accounting for the uncertainty of published prognostic model estimates.

    Science.gov (United States)

    Young, Tracey A; Thompson, Simon

    2004-01-01

    Reported is the importance of properly reflecting uncertainty associated with prognostic model estimates when calculating the survival benefit of a treatment or technology, using liver transplantation as an example. Monte Carlo simulation techniques were used to account for the uncertainty of prognostic model estimates using the standard errors of the regression coefficients and their correlations. These methods were applied to patients with primary biliary cirrhosis undergoing liver transplantation using a prognostic model from a historic cohort who did not undergo transplantation. The survival gain over 4 years from transplantation was estimated. Ignoring the uncertainty in the prognostic model, the estimated survival benefit of liver transplantation was 16.7 months (95 percent confidence interval [CI], 13.5 to 20.1), and was statistically significant (p important that the precision of regression coefficients is available for users of published prognostic models. Ignoring this additional information substantially underestimates uncertainty, which can then impact misleadingly on policy decisions.

  16. Modeling self on others: An import theory of subjectivity and selfhood.

    Science.gov (United States)

    Prinz, Wolfgang

    2017-03-01

    This paper outlines an Import Theory of subjectivity and selfhood. Import theory claims that subjectivity is initially perceived as a key feature of other minds before it then becomes imported from other minds to own minds whereby it lays the ground for mental selfhood. Import theory builds on perception-production matching, which in turn draws on both representational mechanisms and social practices. Representational mechanisms rely on common coding of perception and production. Social practices rely on action mirroring in dyadic interactions. The interplay between mechanisms and practices gives rise to model self on others. Individuals become intentional agents in virtue of perceiving others mirroring themselves. The outline of the theory is preceded by an introductory section that locates import theory in the broader context of competing approaches, and it is followed by a concluding section that assesses import theory in terms of empirical evidence and explanatory power.

  17. Effects of preservatives on stable isotope analyses of four marine species

    Science.gov (United States)

    Carabel, Sirka; Verísimo, Patricia; Freire, Juan

    2009-04-01

    The aim of the present study is to quantify the effect of formalin-ethanol preservation on the carbon and nitrogen stable isotope signatures of four taxonomical groups of marine species ( Himanthalia elongata, Anemonia sulcata, Mytilus galloprovincialis and Patella vulgata). To examine temporal changes in the effects of preservation and to determine if preservation induced predictable shifts in δ13C and δ15N signatures, repeated analyses were carried out after 6, 12 and 24 months of preservation. Data from our study showed highly variable effects of the formalin-ethanol preservation on carbon and nitrogen isotope signatures between species. The use of a general correction factor was not possible, or else it should be species-specific. Differences in nitrogen isotopic values between preserved and unpreserved samples were minor compared to the assumed enrichment between trophic levels. The combined use of data from preserved and unpreserved samples could lead to biases in the estimation of the trophic level of organisms. Changes that preservatives caused in carbon values were variable between species and not always small enough to be ignored. So the use of data from preserved samples could change the interpretation of the mixing models used to determine the importance of multiple sources of carbon. In order to elucidate the effects that preservatives have in other species, further studies will be necessary.

  18. Importance of fossil fuel emission uncertainties over Europe for CO2 modeling: model intercomparison

    Directory of Open Access Journals (Sweden)

    F. Delage

    2011-07-01

    Full Text Available Inverse modeling techniques used to quantify surface carbon fluxes commonly assume that the uncertainty of fossil fuel CO2 (FFCO2 emissions is negligible and that intra-annual variations can be neglected. To investigate these assumptions, we analyzed the differences between four fossil fuel emission inventories with spatial and temporal differences over Europe and their impact on the model simulated CO2 concentration. Large temporal flux variations characterize the hourly fields (~40 % and ~80 % for the seasonal and diurnal cycles, peak-to-peak and annual country totals differ by 10 % on average and up to 40 % for some countries (i.e., the Netherlands. These emissions have been prescribed to seven different transport models, resulting in 28 different FFCO2 concentrations fields. The modeled FFCO2 concentration time series at surface sites using time-varying emissions show larger seasonal cycles (+2 ppm at the Hungarian tall tower (HUN and smaller diurnal cycles in summer (−1 ppm at HUN than when using constant emissions. The concentration range spanned by all simulations varies between stations, and is generally larger in winter (up to ~10 ppm peak-to-peak at HUN than in summer (~5 ppm. The contribution of transport model differences to the simulated concentration std-dev is 2–3 times larger than the contribution of emission differences only, at typical European sites used in global inversions. These contributions to the hourly (monthly std-dev's amount to ~1.2 (0.8 ppm and ~0.4 (0.3 ppm for transport and emissions, respectively. First comparisons of the modeled concentrations with 14C-based fossil fuel CO2 observations show that the large transport differences still hamper a quantitative evaluation/validation of the emission inventories. Changes in the estimated monthly biosphere flux (Fbio over Europe, using two inverse modeling approaches, are relatively small (less that 5 % while changes in annual Fbio (up to ~0.15 % GtC yr−1 are only

  19. Preservation of Newspapers: Theoretical Approaches and Practical Achievements

    Science.gov (United States)

    Hasenay, Damir; Krtalic, Maja

    2010-01-01

    The preservation of newspapers is the main topic of this paper. A theoretical overview of newspaper preservation is given, with an emphasis on the importance of a systematic and comprehensive approach. Efficient newspaper preservation implies understanding the meaning of preservation in general, as well as understanding specific approaches,…

  20. Logoplaste : how business models can play an important role in the achievement of sustained competitive advantage

    OpenAIRE

    Pita, Miguel Vieira

    2011-01-01

    Dissertation title: Logoplaste: How Business Models can play an important role in the achievement of Sustained Competitive Advantage Author: Miguel Vieira Pita The following dissertation gives focus to the case study of Logoplaste, a successful Portuguese company where strategy plays an important role in the short and long term success of the company. Focusing on writing a dissertation that gives highlight to the creation and development of the firm’s valuable resources and ...

  1. Importance of demand modelling in network water quality models: a review

    NARCIS (Netherlands)

    Blokker, E.J.M.; Vreeburg, J.H.G.; Buchberger, S.G.; Van Dijk, J.C.

    2008-01-01

    Today, there is a growing interest in network water quality modelling. The water quality issues of interest relate to both dissolved and particulate substances. For dissolved substances the main interest is in residual chlorine and (microbiological) contaminant propagation; for particulate substance

  2. Importance of demand modelling in network water quality models: a review

    NARCIS (Netherlands)

    Blokker, E.J.M.; Vreeburg, J.H.G.; Buchberger, S.G.; Van Dijk, J.C.

    2008-01-01

    Today, there is a growing interest in network water quality modelling. The water quality issues of interest relate to both dissolved and particulate substances. For dissolved substances the main interest is in residual chlorine and (microbiological) contaminant propagation; for particulate substance

  3. Importance of fossil fuel emission uncertainties over Europe for CO2 modeling: model intercomparison

    NARCIS (Netherlands)

    Peylin, P.; Houweling, S.; Krol, M.C.|info:eu-repo/dai/nl/078760410; Karstens, U.; Pieterse, G.|info:eu-repo/dai/nl/304840858; Ciais, P.; Heimann, M.

    2011-01-01

    Inverse modeling techniques used to quantify surface carbon fluxes commonly assume that the uncertainty of fossil fuel CO2 (FFCO2) emissions is negligible and that intra-annual variations can be neglected. To investigate these assumptions, we analyzed the differences between four fossil fuel

  4. A holistic approach to bit preservation

    DEFF Research Database (Denmark)

    Zierau, Eld

    2012-01-01

    Purpose: The purpose of this paper is to point out the importance of taking a holistic approach to bit preservation when setting out to find an optimal bit preservation solution for specific digital materials. In the last decade there has been an increasing awareness that bit preservation, which...... preservation strategies as well as pointing to how such strategies can be evaluated. Research limitations/implications The operational results described here are still missing work to be fully operational. However, the holistic approach is in itself an important result. Furthermore, in spite...

  5. Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model

    Energy Technology Data Exchange (ETDEWEB)

    Roth, R; Navratil, P

    2007-05-22

    We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a dramatic reduction of the basis dimension. We analyze the validity and efficiency of this truncation scheme using different realistic nucleon-nucleon interactions and compare to conventional no-core shell model calculations for {sup 4}He and {sup 16}O. Then, we present the first converged calculations for the ground state of {sup 40}Ca within no-core model spaces including up to 16{h_bar}{Omega}-excitations using realistic low-momentum interactions. The scheme is universal and can be easily applied to other quantum many-body problems.

  6. AN ECONOMIC MODEL OF U.S. IMPORTS OF BUTTER AND MILK FAT PRODUCTS

    OpenAIRE

    Bailey, Kenneth W.; Wu, Zhen

    2005-01-01

    This study developed a model to explain monthly imports of butter and butter substitutes. The U.S. imports butter and other high milk fat products that can substitute for a strict definition of butter. These products include dairy spreads, butter substitutes, anhydrous milk fat, and food preparations. The U.S. imports these high milk fat products under a tariff-rate quota system (TRQ) implemented by the World Trade Organization (WTO). This study quantified all the milk fat contained in U.S. b...

  7. Exploratory regression analysis: a tool for selecting models and determining predictor importance.

    Science.gov (United States)

    Braun, Michael T; Oswald, Frederick L

    2011-06-01

    Linear regression analysis is one of the most important tools in a researcher's toolbox for creating and testing predictive models. Although linear regression analysis indicates how strongly a set of predictor variables, taken together, will predict a relevant criterion (i.e., the multiple R), the analysis cannot indicate which predictors are the most important. Although there is no definitive or unambiguous method for establishing predictor variable importance, there are several accepted methods. This article reviews those methods for establishing predictor importance and provides a program (in Excel) for implementing them (available for direct download at http://dl.dropbox.com/u/2480715/ERA.xlsm?dl=1) . The program investigates all 2(p) - 1 submodels and produces several indices of predictor importance. This exploratory approach to linear regression, similar to other exploratory data analysis techniques, has the potential to yield both theoretical and practical benefits.

  8. Determining relative importance of variables in developing and validating predictive models

    Directory of Open Access Journals (Sweden)

    Atenafu Eshetu G

    2009-09-01

    Full Text Available Abstract Background Multiple regression models are used in a wide range of scientific disciplines and automated model selection procedures are frequently used to identify independent predictors. However, determination of relative importance of potential predictors and validating the fitted models for their stability, predictive accuracy and generalizability are often overlooked or not done thoroughly. Methods Using a case study aimed at predicting children with acute lymphoblastic leukemia (ALL who are at low risk of Tumor Lysis Syndrome (TLS, we propose and compare two strategies, bootstrapping and random split of data, for ordering potential predictors according to their relative importance with respect to model stability and generalizability. We also propose an approach based on relative increase in percentage of explained variation and area under the Receiver Operating Characteristic (ROC curve for developing models where variables from our ordered list enter the model according to their importance. An additional data set aimed at identifying predictors of prostate cancer penetration is also used for illustrative purposes. Results Age is chosen to be the most important predictor of TLS. It is selected 100% of the time using the bootstrapping approach. Using the random split method, it is selected 99% of the time in the training data and is significant (at 5% level 98% of the time in the validation data set. This indicates that age is a stable predictor of TLS with good generalizability. The second most important variable is white blood cell count (WBC. Our methods also identified an important predictor of TLS that was otherwise omitted if relying on any of the automated model selection procedures alone. A group at low risk of TLS consists of children younger than 10 years of age, without T-cell immunophenotype, whose baseline WBC is 9/L and palpable spleen is Conclusion Our model selection procedures based on bootstrap re-sampling and

  9. IMPORTANCE OF DIFFERENT MODELS IN DECISION MAKING, EXPLAINING THE STRATEGIC BEHAVIOR IN ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Cristiano de Oliveira Maciel

    2006-11-01

    Full Text Available This study is about the different models of decision process analyzing the organizational strategy. The article presents the strategy according to a cognitive approach. The discussion about that approach has three models of decision process: rational actor model, organizational behavior, and political model. These models, respectively, present some improvement in the decision making results, search for a good decision facing the cognitive restrictions of the administrator, and lots of talks for making a decision. According to the emphasis of each model, the possibilities for analyzing the strategy are presented. The article also shows that it is necessary to take into account the three different ways of analysis. That statement is justified once the analysis as well as the decision making become more complex, mainly those which are more important for the organizations.

  10. A Framework for Distributed Preservation Workflows

    Directory of Open Access Journals (Sweden)

    Rainer Schmidt

    2010-07-01

    Full Text Available The Planets Project is developing a service-oriented environment for the definition and evaluation of preservation strategies for human-centric data. It focuses on the question of logically preserving digital materials, as opposed to the physical preservation of content bit-streams. This includes the development of preservation tools for the automated characterisation, migration, and comparison of different types of Digital Objects as well as the emulation of their original runtime environment in order to ensure long-time access and interpretability. The Planets integrated environment provides a number of end-user applications that allow data curators to execute and scientifically evaluate preservation experiments based on composable preservation services. In this paper, we focus on the middleware and programming model and show how it can be utilised in order to create complex preservation workflows.

  11. Modeling the Variability and Importance of Snow Sublimation in the North-Central Colorado Rocky Mountains

    Science.gov (United States)

    Sexstone, G. A.; Clow, D. W.; Fassnacht, S. R.; Liston, G. E.; Hiemstra, C. A.; Knowles, J. F.

    2016-12-01

    In the western United States, where seasonal snowmelt is a critical water resource for ecological and anthropological needs, snow sublimation (sublimation) has been suggested by many studies to be an important component of the snow cover mass balance. However, few studies have evaluated the spatial and temporal variability of sublimation in complex mountainous environments. In this study, we use a process-based snow model (SnowModel) and eddy covariance (EC) measurements to evaluate the variability and importance of sublimation across the north-central Colorado Rocky Mountains for 5 water years (WY 2011 - WY 2015). In-situ EC observations of sublimation compare well with modeled sublimation at sites dominated by surface and canopy components of sublimation, but model verification of blowing sublimation in alpine areas was not feasible because these fluxes often occur when snow is in turbulent suspension, which cannot always be resolved by EC instrumentation. Model simulations showed substantial spatial and temporal variability of sublimation across the study domain. Sublimation rates were found to exhibit differences across landscape characteristics such as elevation and land cover. Land cover type was an important driver of snow sublimation variability, with substantial sublimation occurring in alpine and forested areas, and relatively lower sublimation occurring in open areas below treeline. Sublimation from forested areas accounted for the majority of modeled sublimation losses across the study domain and highlights the importance of sublimation from snow stored in the forest canopy in this region. Additionally, the interannual differences in total sublimation were strongly linked with seasonal snowfall amounts. Results from this study suggest that snow sublimation is a significant component of the winter water balance and have important implications for future water management and decision making.

  12. Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model

    Science.gov (United States)

    Dutkiewicz, S.; Hickman, A. E.; Jahn, O.; Gregg, W. W.; Mouw, C. B.; Follows, M. J.

    2015-02-01

    We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical-ecosystem in a dynamic three-dimensional physical framework. The radiative transfer component resolves spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (the phytoplankton community, detrital particles, and coloured dissolved organic matter, CDOM). The model is evaluated against in situ observed and satellite derived products. In particular we compare to concurrently measured biogeochemical, ecosystem and optical data along a north-south transect of the Atlantic Ocean. The simulation captures the patterns and magnitudes of these data, and estimates surface upwelling irradiance analogous to that observed by ocean colour satellite instruments. We conduct a series of sensitivity experiments to demonstrate, globally, the relative importance of each of the water constituents, and the crucial feedbacks between the light field and the relative fitness of phytoplankton types, and the biogeochemistry of the ocean. CDOM has proportionally more importance at short wavelengths and in more productive waters, phytoplankton absorption is especially important at the deep chlorophyll a (Chl a) maximum, and absorption by water molecules is relatively most important in the highly oligotrophic gyres. Sensitivity experiments in which absorption by any of the optical constituents was increased led to a decrease in the size of the oligotrophic regions of the subtropical gyres: lateral nutrient supplies were enhanced as a result of decreasing high latitude productivity. Scattering does not as strongly affect the ecosystem and biogeochemistry fields within the water column but is important for setting the surface upwelling irradiance, and hence sea surface reflectance. Having a model capable of capturing bio-optical feedbacks will be important for

  13. Prednisolone as preservation additive prevents from ischemia reperfusion injury in a rat model of orthotopic lung transplantation.

    Directory of Open Access Journals (Sweden)

    Patrick Paulus

    Full Text Available The lung is, more than other solid organs, susceptible for ischemia reperfusion injury after orthotopic transplantation. Corticosteroids are known to potently suppress pro-inflammatory processes when given in the post-operative setting or during rejection episodes. Whereas their use has been approved for these clinical indications, there is no study investigating its potential as a preservation additive in preventing vascular damage already in the phase of ischemia. To investigate these effects we performed orthotopic lung transplantations (LTX in the rat. Prednisolone was either added to the perfusion solution for lung preservation or omitted and rats were followed for 48 hours after LTX. Prednisolone preconditioning significantly increased survival and diminished reperfusion edema. Hypoxia induced vasoactive cytokines such as VEGF were reduced. Markers of leukocyte invasiveness like matrix metalloprotease (MMP-2, or common pro-inflammatory molecules like the CXCR4 receptor or the chemokine (C-C motif ligand (CCL-2 were downregulated by prednisolone. Neutrophil recruitment to the grafts was only increased in Perfadex treated lungs. Together with this, prednisolone treated animals displayed significantly reduced lung protein levels of neutrophil chemoattractants like CINC-1, CINC-2α/β and LIX and upregulated tissue inhibitor of matrix metalloproteinase (TIMP-1. Interestingly, lung macrophage invasion was increased in both, Perfadex and prednisolone treated grafts, as measured by MMP-12 or RM4. Markers of anti-inflammatory macrophage transdifferentiation like MRC-1, IL-13, IL-4 and CD163, significantly correlated with prednisolone treatment. These observations lead to the conclusion that prednisolone as an additive to the perfusion solution protects from hypoxia triggered danger signals already in the phase of ischemia and thus reduces graft edema in the phase of reperfusion. Additionally, prednisolone preconditioning might also lead to

  14. Water quality modeling based on landscape analysis: Importance of riparian hydrology

    Science.gov (United States)

    Thomas Grabs

    2010-01-01

    Several studies in high-latitude catchments have demonstrated the importance of near-stream riparian zones as hydrogeochemical hotspots with a substantial influence on stream chemistry. An adequate representation of the spatial variability of riparian-zone processes and characteristics is the key for modeling spatiotemporal variations of stream-water quality. This...

  15. The importance of weather data in crop growth simulation models and assessment of climatic change effects

    NARCIS (Netherlands)

    Nonhebel, S.

    1993-01-01

    Yields of agricultural crops are largely determined by the weather conditions during the growing season. Weather data are therefore important input variables for crop growth simulation models. In practice, these data are accepted at their face value. This is not realistic. Like all measured

  16. Improving Adaptive Importance Sampling Simulation of Markovian Queueing Models using Non-parametric Smoothing

    NARCIS (Netherlands)

    Woudt, Edwin; de Boer, Pieter-Tjerk; van Ommeren, Jan C.W.

    2007-01-01

    Previous work on state-dependent adaptive importance sampling techniques for the simulation of rare events in Markovian queueing models used either no smoothing or a parametric smoothing technique, which was known to be non-optimal. In this paper, we introduce the use of kernel smoothing in this con

  17. Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model

    Directory of Open Access Journals (Sweden)

    S. Dutkiewicz

    2015-07-01

    This new model that captures bio-optical feedbacks will be important for improving our understanding of the role of light and optical constituents on ocean biogeochemistry, especially in a changing environment. Further, resolving surface upwelling irradiance will make it easier to connect to satellite-derived products in the future.

  18. The Importance of Positive Self-Concept for Islamic Education Teachers as a Role Model

    Science.gov (United States)

    Muhamad, Nurul Asiah Fasehah; Hamzah, Mohd Isa; Tamuri, Ab. Halim; Ja'afar, Noornajihan; Ghazali, Norzulaili Mohd; Amat, Robiatul Adawiyah Mohd; Raus, Norakyairee Mohd; Hassan, Syed Najihuddin Syed

    2013-01-01

    This study embarks from the great and huge responsibility of teachers nowadays especially the IRT (Islamic religious teachers). As the role model of students, they play an important task especially in producing the good Muslim character. Therefore, their job not only focuses on the content of subject but becomes wider in scope, more than other…

  19. Conceptual Resources in Self-developed Explanatory Models: The importance of integrating conscious and intuitive knowledge

    Science.gov (United States)

    Cheng, Meng-Fei; Brown, David E.

    2010-11-01

    This study explores the spontaneous explanatory models children construct, critique, and revise in the context of tasks in which children need to predict, observe, and explain phenomena involving magnetism. It further investigates what conceptual resources students use, and in what ways they use them, to construct explanatory models, and the obstacles preventing them from constructing a useful explanatory model. Our findings indicate that several of the children were able to construct explanatory models. However, of the six children interviewed multiple times (three third-graders and three sixth-graders), only one was consistently able to critique and revise her models to arrive at a consistent, coherent, and sophisticated explanatory model. Connecting intuitive knowledge and abstract knowledge was important in her construction of a coherent and sophisticated explanatory model. Students who relied only on intuitive knowledge constructed tentative and non-sophisticated explanatory models. Students who relied only on verbal-symbolic knowledge at an abstract level without connection with their intuition also did not construct coherent and sophisticated models. These results indicate that instruction should help students to become meta-conceptually aware and connect their verbal-symbolic knowledge and intuition in order to construct explanatory models to make sense of abstract scientific knowledge.

  20. Importance of coherence in models of mid-infrared quantum cascade laser gain spectra

    Science.gov (United States)

    Cui, Yuzhang I.; Harter, Michael P.; Dikmelik, Yamac; Hoffman, Anthony J.

    2017-09-01

    We present a three-level model based on a density matrix to examine the influence of coherence and dephasing on the gain spectrum of mid-infrared quantum cascade lasers. The model is used to examine a quantum cascade active region with multiple optical transitions. We show how coherence can explain the origin of additional peaks in the gain spectrum. We also analyze the spectra calculated using the three-level model with a rate equation formalism to demonstrate the importance of considering interface roughness and limitations of the rate equation formalism. Specifically, we present how interface roughness influences the broadening and oscillator strength that are recovered using a rate equation analysis. The results of this work are important when considering the design of active regions with multiple optical transitions and could lead to devices with improved performance.

  1. Resampling: An improvement of importance sampling in varying population size models.

    Science.gov (United States)

    Merle, C; Leblois, R; Rousset, F; Pudlo, P

    2017-04-01

    Sequential importance sampling algorithms have been defined to estimate likelihoods in models of ancestral population processes. However, these algorithms are based on features of the models with constant population size, and become inefficient when the population size varies in time, making likelihood-based inferences difficult in many demographic situations. In this work, we modify a previous sequential importance sampling algorithm to improve the efficiency of the likelihood estimation. Our procedure is still based on features of the model with constant size, but uses a resampling technique with a new resampling probability distribution depending on the pairwise composite likelihood. We tested our algorithm, called sequential importance sampling with resampling (SISR) on simulated data sets under different demographic cases. In most cases, we divided the computational cost by two for the same accuracy of inference, in some cases even by one hundred. This study provides the first assessment of the impact of such resampling techniques on parameter inference using sequential importance sampling, and extends the range of situations where likelihood inferences can be easily performed.

  2. Preservation of striatal tissue and behavioral function after neural stem cell transplantation in a rat model of Huntington's disease.

    Science.gov (United States)

    Roberts, T J; Price, J; Williams, S C R; Modo, M

    2006-01-01

    Cell replacement has the potential to become a frontline therapy to remedy behavioral impairments in Huntington's disease. To determine the efficacy of stem cell transplantation, behavioral assessment and in vivo monitoring of the lesion environment are paramount. We here demonstrate that neural stem cells from the MHP36 cell line prevented the development of a deficit on the beam walk test while providing partial recovery of learning in the water maze. However, no beneficial effect on rats' impairment in the staircase test was observed. By quantification of the lesion from serial magnetic resonance images, no effect of neural stem cells on lesion volume was observed. Instead, a preservation of striatal volume over time and its correlation with performance on the beam walk test suggested that sparing of behavioral function was associated with a stagnation of ongoing tissue loss rather than a reduction in lesion size. Serial imaging therefore warrants further implementation in clinical trials of neural grafts to monitor in vivo changes in the damaged brain due to transplantation.

  3. An accurate simulation model for single-photon avalanche diodes including important statistical effects

    Science.gov (United States)

    Qiuyang, He; Yue, Xu; Feifei, Zhao

    2013-10-01

    An accurate and complete circuit simulation model for single-photon avalanche diodes (SPADs) is presented. The derived model is not only able to simulate the static DC and dynamic AC behaviors of an SPAD operating in Geiger-mode, but also can emulate the second breakdown and the forward bias behaviors. In particular, it considers important statistical effects, such as dark-counting and after-pulsing phenomena. The developed model is implemented using the Verilog-A description language and can be directly performed in commercial simulators such as Cadence Spectre. The Spectre simulation results give a very good agreement with the experimental results reported in the open literature. This model shows a high simulation accuracy and very fast simulation rate.

  4. How important is a detailed hydrological representation when modelling soil carbon dynamics in Chinese red soils.

    Science.gov (United States)

    Oyesiku-Blakemore, Joseph; Verrot, Lucile; Geris, Josie; Zhang, Ganlin; Peng, Xinhua; Hallett, Paul; Smith, Jo

    2017-04-01

    Soil carbon and nitrogen processing are strongly influenced by the hydrology of soils. When simulating these processes models represent soil hydrology in some way. The hydrological components of soil carbon and nitrogen models vary greatly in their complexity, as does the burden of simulation time and data requirements. Hydrology specific models, such as Hydrus, have more detailed representations of soil hydrology than those used in some soil carbon and nitrogen models, such as ECOSSE, and can provide a more accurate and precise description of the movement and content of water in soil. Moisture content is one of the key variables controlling the processing of carbon and nitrogen in soil models. A higher soil moisture content results in increased methane production through the anaerobic decomposition of soil carbon pools. It also alters the rate at which aerobic decomposition occurs, with low and high soil moisture contents limiting the decomposition of SOC. An inaccurate estimate of soil moisture will introduce errors in the estimated rates of model SOC transformations, which would result in errors in the simulated SOC. In order to shed light on this uncertainty we use the same input data to simulate soil moisture contents in a Red Soil region of China, using both the ECOSSE model and Hydrus 2D. We compare the simulations of both models with measurements of soil moisture at the site and each other. We highlight where the models differ and identify the conditions under which errors are likely to occur. We then simulate SOC dynamics using the ECOSSE model and its original hydrology with the ECOSSE model simulations using the Hydrus 2D simulations. This shows the importance of including a detailed representation of soil moisture when simulating soil organic matter dynamics.

  5. Modelling importance of sediment effects on fate and transport of enterococci in the Severn Estuary, UK.

    Science.gov (United States)

    Gao, Guanghai; Falconer, Roger A; Lin, Binliang

    2013-02-15

    The paper detailed a water quality modelling study of a hyper-tidal estuary, undertaken to assess the impact of various bacteria input loads on the receiving waters in a coastal basin in the UK, by using the model developed in previous study of the same authors enterococci, used as the indicators for bathing water quality under the new European Union (EU) Bathing Water Directive, were numerically modelled using a hydro-environmental model. In particular, the numerical model used in this study includes the effects of sediment on bacteria transport processes in surface water. Finally, the importance of sediment bacteria inputs on the bathing water quality was also investigated under different weather and tidal condition. During spring tide, the bacteria input from the bed sediments are dominant for both wet and dry weather conditions. During neap tides and during dry weather conditions the inputs of bacteria from the bed sediment were still dominant, but during wet weather conditions the inputs from river were dominant. Under different tidal flow conditions some parameters had a more significant role than others. During high flow conditions the sediment re-suspensions processes were dominant, therefore the bed bacteria concentrations played a dominant role on the overall bacteria concentration levels in the water column. In contrast, during low flow conditions sediment deposition prevails and bacteria are removed from the water column. The partition coefficient was found to be more important than the bed bacteria concentrations, during low flow conditions.

  6. Important limitations in the modeling of activated sludge : biased calibration of the hydrolysis process

    DEFF Research Database (Denmark)

    Insel, G.; Gul, Ö.K.; Orhon, D.

    2002-01-01

    ), provides the majority of the required experimental database. However, currently used procedures still involve a number of basic and practical problems. Model evaluation of the OUR data may generate a distorted image of the processes involved. Hydrolysis is the most important, yet the most vulnerable...... process as far as the experimental assessment of accurate kinetic parameters is concerned. This study intends to provide an overview of major experimental limitations in the modeling of activated sludge, with emphasis on the appropriate experimental design for the assessment of the hydrolysis rate....

  7. PRESERVING A TRADITION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    COVER STORY The Chinese art of paper cutting has long been a popular pastime in the country’s rural areas.For more than 1,000 years,farming families have used it as a method for decorating their homes,but the tradition has struggled for survival in recent years.In Yanchuan County in China’s northwestern Shaanxi Province,however,the art form has experienced a revival thanks to the efforts of a local woman.Paper cutting master Gao Fenglian has invested her own money in establishing a paper cutting gallery in the region.The craft’s growing popularity has also fuelled a new wave of people wanting to learn how to cut.More than 10,000 of the county’s 200,000 are now skilled in the ancient craft,and its revival could serve as a model for the preservation of other Chinese traditions.

  8. Package Formats for Preserved Digital Material

    DEFF Research Database (Denmark)

    Zierau, Eld

    2012-01-01

    This paper presents an investigation of the best suitable package formats for long term digital preservation. The choice of a package format for preservation is crucial for future access, thus a thorough analysis of choice is important. The investigation presented here covers setting up requireme...

  9. Towards Building a Blog Preservation Platform

    CERN Document Server

    Kasioumis, Nikos; Kalb, Hendrik

    2014-01-01

    Social media content and user participation has increased dramatically since the advent of Web 2.0. Blogs have become relevant to every aspect of business and personal life. Nevertheless, we do not have the right tools to aggregate and preserve blog content correctly, as well as to manage blog archives effectively. Given the rising importance of blogs, it is crucial to build systems to facilitate blog preservation, safeguarding an essential part of our heritage that will prove valuable for current and future generations. In this paper, we present our work in progress towards building a novel blog preservation platform featuring robust digital preservation, management and dissemination facilities for blogs. This work is part of the BlogForever project which is aiming to make an impact to the theory and practice of blog preservation by creating guidelines and software that any individual or organization could use to preserve their blogs.

  10. Evaluation of factors important in modeling plasma concentrations of tetracycline hydrochloride administered in water in swine.

    Science.gov (United States)

    Mason, Sharon E; Almond, Glen W; Riviere, Jim E; Baynes, Ronald E

    2012-10-01

    To model the plasma tetracycline concentrations in swine (Sus scrofa domestica) treated with medication administered in water and determine the factors that contribute to the most accurate predictions of measured plasma drug concentrations. Plasma tetracycline concentrations measured in blood samples from 3 populations of swine. Data from previous studies provided plasma tetracycline concentrations that were measured in blood samples collected from 1 swine population at 0, 4, 8, 12, 24, 32, 48, 56, 72, 80, 96, and 104 hours and from 2 swine populations at 0, 12, 24, 48, and 72 hours hours during administration of tetracycline hydrochloride dissolved in water. A 1-compartment pharmacostatistical model was used to analyze 5 potential covariate schemes and determine factors most important in predicting the plasma concentrations of tetracycline in swine. 2 models most accurately predicted the tetracycline plasma concentrations in the 3 populations of swine. Factors of importance were body weight or age of pig, ambient temperature, concentration of tetracycline in water, and water use per unit of time. The factors found to be of importance, combined with knowledge of the individual pharmacokinetic and chemical properties of medications currently approved for administration in water, may be useful in more prudent administration of approved medications administered to swine. Factors found to be important in pharmacostatistical models may allow prediction of plasma concentrations of tetracycline or other commonly used medications administered in water. The ability to predict in vivo concentrations of medication in a population of food animals can be combined with bacterial minimum inhibitory concentrations to decrease the risk of developing antimicrobial resistance.

  11. The Importance of Cognitive Phenotypes in Experimental Modeling of Animal Anxiety and Depression

    OpenAIRE

    Kalueff, Allan V.; Murphy, Dennis L.

    2007-01-01

    Cognitive dysfunctions are commonly seen in many stress-related disorders, including anxiety and depression—the world's most common neuropsychiatric illnesses. Various genetic, pharmacological, and behavioral animal models have long been used to establish animal anxiety-like and depression-like phenotypes, as well as to assess their memory, learning, and other cognitive functions. Mounting clinical and animal evidences strongly supports the notion that disturbed cognitions represent an import...

  12. Phylogenetic Gaussian process model for the inference of functionally important regions in protein tertiary structures.

    Science.gov (United States)

    Huang, Yi-Fei; Golding, G Brian

    2014-01-01

    A critical question in biology is the identification of functionally important amino acid sites in proteins. Because functionally important sites are under stronger purifying selection, site-specific substitution rates tend to be lower than usual at these sites. A large number of phylogenetic models have been developed to estimate site-specific substitution rates in proteins and the extraordinarily low substitution rates have been used as evidence of function. Most of the existing tools, e.g. Rate4Site, assume that site-specific substitution rates are independent across sites. However, site-specific substitution rates may be strongly correlated in the protein tertiary structure, since functionally important sites tend to be clustered together to form functional patches. We have developed a new model, GP4Rate, which incorporates the Gaussian process model with the standard phylogenetic model to identify slowly evolved regions in protein tertiary structures. GP4Rate uses the Gaussian process to define a nonparametric prior distribution of site-specific substitution rates, which naturally captures the spatial correlation of substitution rates. Simulations suggest that GP4Rate can potentially estimate site-specific substitution rates with a much higher accuracy than Rate4Site and tends to report slowly evolved regions rather than individual sites. In addition, GP4Rate can estimate the strength of the spatial correlation of substitution rates from the data. By applying GP4Rate to a set of mammalian B7-1 genes, we found a highly conserved region which coincides with experimental evidence. GP4Rate may be a useful tool for the in silico prediction of functionally important regions in the proteins with known structures.

  13. Transtheoretical model for behavior changes: an important tool when adopting active life

    OpenAIRE

    Álvarez, Carlos

    2008-01-01

    Despite the worship of beauty that has ruled this globalized society and the importance of physical activity for the prevention of cardio-degenerative diseases (US.DHHS, 1996), sedentary behavior continues to increase in the population.  What strategies can be used by professionals of human movement to make the population physically active? It is at this point where the Transtheoretical Model appears as an innovative option that greatly surpasses the classic short-term biological intervention...

  14. Numerical Study of φ4 Model by Potential Importance Sampling Method

    Institute of Scientific and Technical Information of China (English)

    YUAN Qing-Xin; DING Guo-Hui

    2006-01-01

    We investigate the phenomena of spontaneous symmetry breaking for φ4 modelon a square lattice in the parameter space by using the potential importance samplingmethod, which was proposed by Milchev, Heermann, and Binder [J. Stat. Phys. 44 (1986) 749]. The critical values of the parameters allow us to determine the phase diagram of the model. At the same time, some relevant quantities such as susceptibility and specific heat are also obtained.

  15. Epimenides: Interoperability Reasoning for Digital Preservation

    NARCIS (Netherlands)

    Kargakis, Yannis; Tzitzikas, Yannis; van Horik, M.P.M.

    2014-01-01

    This paper presents Epimenides, a system that implements a novel interoperability dependency reasoning approach for assisting digital preservation activities. A distinctive feature is that it can model also converters and emulators, and the adopted modelling approach enables the automatic reasoning

  16. {sup 57}Fe Mössbauer spectroscopy used to develop understanding of a diamond preservation index model

    Energy Technology Data Exchange (ETDEWEB)

    Yambissa, M. T.; Forder, S. D.; Bingham, P. A., E-mail: p.a.bingham@shu.ac.uk [Sheffield Hallam University, Materials and Engineering Research Institute Faculty of Arts, Computing, Engineering and Sciences (United Kingdom)

    2016-12-15

    {sup 57}Fe Mössbauer spectroscopy has provided precise and accurate iron redox ratios Fe{sup 2+}/Fe{sup 3+} in ilmenite, FeTiO{sub 3}, found within kimberlite samples from the Catoca and Camatxia kimberlite pipes from N.E. Angola. Ilmenite is one of the key indicator minerals for diamond survival and it is also one of the iron-bearing minerals with iron naturally occurring in one or both of the oxidation states Fe{sup 3+} and Fe{sup 2+}. For this reason it is a good indicator for studying oxygen fugacities (fO{sub 2}) in mineral samples, which can then be related to iron redox ratios, Fe{sup 2+}/Fe{sup 3+}. In this paper we demonstrate that the oxidation state of the ilmenite mineral inclusion from sampled kimberlite rock is a key indicator of the oxidation state of the host kimberlite assemblage, which in turn determines the genesis of diamond, grade variation and diamond quality. Ilmenite samples from the two different diamondiferous kimberlite localities (Catoca and Camatxia) in the Lucapa graben, N.E. Angola, were studied using Mössbauer spectroscopy and X-Ray Diffractometry, in order to infer the oxidation state of their source regions in the mantle, oxygen partial pressure and diamond preservation conditions. The iron redox ratios, obtained using Mössbauer spectroscopy, show that the Catoca diamond kimberlite is more oxidised than kimberlite found in the Camatxia pipe, which is associated within the same geological tectonic structure. Here we demonstrate that{sup 57}Fe Mössbauer spectroscopy can assist geologists and mining engineers to effectively evaluate and determine whether kimberlite deposits are economically feasible for diamond mining.

  17. Preserving reptiles for research

    Science.gov (United States)

    Gotte, Steve W.; Jacobs, Jeremy F.; Zug, George R.; Dodd, C. Kenneth

    2016-01-01

    What are voucher specimens and why do we collect them? Voucher specimens are animals and/or their parts that are deposited in a research museum to document the occurrence of a taxon at a specific location in space and time (Pleijel et al., 2008; Reynolds and McDiarmid, 2012). For field biologists, vouchers are the repeatable element of a field study as they allow other biologists, now and in the future, to confirm the identity of species that were studied. The scientific importance of a voucher specimen or series of specimens is that other people are afforded the opportunity to examine the entire animal and confirm or correct identifications. A photographic record is somewhat useful for recording the occurrence of a species, but such records can be insufficient for reliable confirmation of specific identity. Even if a photo shows diagnostic characters of currently recognized taxa, it may not show characters that separate taxa that may be described in the future. Substantial cryptic biodiversity is being found in even relatively well-known herpetofaunas (Crawford et al., 2010), and specimens allow researchers to retroactively evaluate the true diversity in a study as understanding of taxonomy evolves. They enable biologists to study the systematic relationships of populations by quantifying variation in different traits. Specimens are also a source of biological data such as behaviour, ecology, epidemiology, and reproduction through examination of their anatomy, reproductive and digestive tracts, and parasites (Suarez and Tsutsui, 2004). Preserving reptiles as vouchers is not difficult, although doing it properly requires care, effort, and time. Poorly preserved vouchers can invalidate the results and conclusions of your study because of the inability to confirm the identity of your study animals. Good science requires repeatability of observations, and the absence of vouchers or poorly preserved ones prevents such confirmation. Due to space restrictions, we are

  18. [Preservatives in ophthalmology].

    Science.gov (United States)

    Messmer, E M

    2012-11-01

    Preservatives are a legal requirement for eye drops in multidose containers. Moreover, they are necessary for stabilization and intraocular penetration for a number of ophthalmic preparations. Most preservatives act in a relatively unspecific manner as detergents or by oxidative mechanisms and thereby cause side effects at the ocular surface. They may also affect the lens, trabecular meshwork and the retina. Benzalkonium chloride is the most commonly used preservative in ophthalmology and is more toxic than other or newer preservatives, such as polyquaternium-1 (Polyquad), sodium perborate, oxychloro-complex (Purite®) and SofZia. Preservative-free topical medication is highly recommended for patients with ocular surface disease, frequent eye drop administration, proven allergy to preservatives and contact lens wear.

  19. Numerical Considerations for Lagrangian Stochastic Dispersion Models: Eliminating Rogue Trajectories, and the Importance of Numerical Accuracy

    Science.gov (United States)

    Bailey, Brian N.

    2017-01-01

    When Lagrangian stochastic models for turbulent dispersion are applied to complex atmospheric flows, some type of ad hoc intervention is almost always necessary to eliminate unphysical behaviour in the numerical solution. Here we discuss numerical strategies for solving the non-linear Langevin-based particle velocity evolution equation that eliminate such unphysical behaviour in both Reynolds-averaged and large-eddy simulation applications. Extremely large or `rogue' particle velocities are caused when the numerical integration scheme becomes unstable. Such instabilities can be eliminated by using a sufficiently small integration timestep, or in cases where the required timestep is unrealistically small, an unconditionally stable implicit integration scheme can be used. When the generalized anisotropic turbulence model is used, it is critical that the input velocity covariance tensor be realizable, otherwise unphysical behaviour can become problematic regardless of the integration scheme or size of the timestep. A method is presented to ensure realizability, and thus eliminate such behaviour. It was also found that the numerical accuracy of the integration scheme determined the degree to which the second law of thermodynamics or `well-mixed condition' was satisfied. Perhaps more importantly, it also determined the degree to which modelled Eulerian particle velocity statistics matched the specified Eulerian distributions (which is the ultimate goal of the numerical solution). It is recommended that future models be verified by not only checking the well-mixed condition, but perhaps more importantly by checking that computed Eulerian statistics match the Eulerian statistics specified as inputs.

  20. Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model

    Science.gov (United States)

    Dutkiewicz, S.; Hickman, A. E.; Jahn, O.; Gregg, W. W.; Mouw, C. B.; Follows, M. J.

    2015-07-01

    We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical-ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer component resolves the penetration of spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (different phytoplankton functional types; detrital particles; and coloured dissolved organic matter, CDOM). The model is evaluated against in situ-observed and satellite-derived products. In particular we compare to concurrently measured biogeochemical, ecosystem, and optical data along a meridional transect of the Atlantic Ocean. The simulation captures the patterns and magnitudes of these data, and estimates surface upwelling irradiance analogous to that observed by ocean colour satellite instruments. We find that incorporating the different optically important constituents explicitly and including spectral irradiance was crucial to capture the variability in the depth of the subsurface chlorophyll a (Chl a) maximum. We conduct a series of sensitivity experiments to demonstrate, globally, the relative importance of each of the water constituents, as well as the crucial feedbacks between the light field, the relative fitness of phytoplankton types, and the biogeochemistry of the ocean. CDOM has proportionally more importance at attenuating light at short wavelengths and in more productive waters, phytoplankton absorption is relatively more important at the subsurface Chl a maximum, and water molecules have the greatest contribution when concentrations of other constituents are low, such as in the oligotrophic gyres. Scattering had less effect on attenuation, but since it is important for the amount and type of upwelling irradiance, it is crucial for setting sea surface reflectance. Strikingly, sensitivity experiments in which absorption by any of the

  1. Importance of facial physical attractiveness of audiovisual models in descriptions and preferences of children and adolescents.

    Science.gov (United States)

    Ruiz, Cristina; Conde, Elena; Torres, Esteban

    2005-08-01

    We performed a cross-sectional study with three age groups (8, 14, and 17 years) to evaluate developmental differences in stereotyped beliefs about physical attractiveness and the value of this as perceived by the participants. Given the current importance of television in the development of social knowledge, television models were used. The children and adolescents were asked to evaluate, using bipolar open scales, the physical attractiveness, likeableness, generosity, intelligence, fun, and altruism of 12 television models of both sexes, previously selected by judges, as well as the desire to resemble or feel close to the models. Analysis showed developmental differences across age groups both in the concept of physical attractiveness and in stereotyped beliefs about this. As in other areas of social knowledge, the younger children's responses were bipolar, global, and much more stereotyped, while the adolescents introduced subtle distinctions and elaborated their responses. Nevertheless, physical attractiveness appeared a desirable characteristic for all age groups.

  2. Preserving Digital Materials

    CERN Document Server

    Harvey, Ross

    2011-01-01

    This book provides a single-volume introduction to the principles, strategies and practices currently applied by librarians and recordkeeping professionals to the critical issue of preservation of digital information. It incorporates practice from both the recordkeeping and the library communities, taking stock of current knowledge about digital preservation and describing recent and current research, to provide a framework for reflecting on the issues that digital preservation raises in professional practice.

  3. The ZEUS long term data preservation project

    CERN Document Server

    ,

    2016-01-01

    The ZEUS data preservation (ZEUS DP) project assures continued access to the data and documentation related to the experiment. It aims to provide the ability to continue the generation of valuable scientific results from these data in the future. This talk presents analysis opportunities within the ZEUS DP project and its benefits for the physics community. The implications of the preserved data are discussed in the context of current data analyses, verification of contemporary and future theoretical models and the planning of future experiments and analyses. The detailed documentation on the data preservation effort can serve as an example for the data preservation efforts in current and future experiments.

  4. The non-uniformity of fossil preservation.

    Science.gov (United States)

    Holland, Steven M

    2016-07-19

    The fossil record provides the primary source of data for calibrating the origin of clades. Although minimum ages of clades are given by the oldest preserved fossil, these underestimate the true age, which must be bracketed by probabilistic methods based on multiple fossil occurrences. Although most of these methods assume uniform preservation rates, this assumption is unsupported over geological timescales. On geologically long timescales (more than 10 Myr), the origin and cessation of sedimentary basins, and long-term variations in tectonic subsidence, eustatic sea level and sedimentation rate control the availability of depositional facies that preserve the environments in which species lived. The loss of doomed sediments, those with a low probability of preservation, imparts a secular trend to fossil preservation. As a result, the fossil record is spatially and temporally non-uniform. Models of fossil preservation should reflect this non-uniformity by using empirical estimates of fossil preservation that are spatially and temporally partitioned, or by using indirect proxies of fossil preservation. Geologically, realistic models of preservation will provide substantially more reliable estimates of the origination of clades.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.

  5. The importance of data quality for generating reliable distribution models for rare, elusive, and cryptic species.

    Science.gov (United States)

    Aubry, Keith B; Raley, Catherine M; McKelvey, Kevin S

    2017-01-01

    The availability of spatially referenced environmental data and species occurrence records in online databases enable practitioners to easily generate species distribution models (SDMs) for a broad array of taxa. Such databases often include occurrence records of unknown reliability, yet little information is available on the influence of data quality on SDMs generated for rare, elusive, and cryptic species that are prone to misidentification in the field. We investigated this question for the fisher (Pekania pennanti), a forest carnivore of conservation concern in the Pacific States that is often confused with the more common Pacific marten (Martes caurina). Fisher occurrence records supported by physical evidence (verifiable records) were available from a limited area, whereas occurrence records of unknown quality (unscreened records) were available from throughout the fisher's historical range. We reserved 20% of the verifiable records to use as a test sample for both models and generated SDMs with each dataset using Maxent. The verifiable model performed substantially better than the unscreened model based on multiple metrics including AUCtest values (0.78 and 0.62, respectively), evaluation of training and test gains, and statistical tests of how well each model predicted test localities. In addition, the verifiable model was consistent with our knowledge of the fisher's habitat relations and potential distribution, whereas the unscreened model indicated a much broader area of high-quality habitat (indices > 0.5) that included large expanses of high-elevation habitat that fishers do not occupy. Because Pacific martens remain relatively common in upper elevation habitats in the Cascade Range and Sierra Nevada, the SDM based on unscreened records likely reflects primarily a conflation of marten and fisher habitat. Consequently, accurate identifications are far more important than the spatial extent of occurrence records for generating reliable SDMs for the

  6. Development and validation of a stochastic model for potential growth of Listeria monocytogenes in naturally contaminated lightly preserved seafood

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Bøknæs, Niels; Dalgaard, Paw

    2015-01-01

    added acetic and/or lactic acids. The stochastic model was developed from an existing deterministic model including the effect of 12 environmental parameters and microbial interaction (O. Mejlholm and P. Dalgaard, Food Microbiology, submitted for publication). Observed maximum population density (MPD......A new stochastic model for the simultaneous growth of Listeria monocytogenes and lactic acid bacteria (LAB) was developed and validated on data from naturally contaminated samples of cold-smoked Greenland halibut (CSGH) and cold-smoked salmon (CSS). During industrial processing these samples were......) values of L. monocytogenes in naturally contaminated samples of CSGH and CSS were accurately predicted by the stochastic model based on measured variability in product characteristics and storage conditions. Results comparable to those from the stochastic model were obtained, when product characteristics...

  7. New alternatives to cosmetics preservation.

    Science.gov (United States)

    Papageorgiou, S; Varvaresou, A; Tsirivas, E; Demetzos, C

    2010-01-01

    In recent years, there is a considerable interest in the development of preservative-free or self-preserving cosmetics. The aim of our work was to develop new cosmetic formulations by replacing chemical preservatives with ingredients with antimicrobial properties that are not legislated as preservatives according to Annex VI of Commission Directive 76/768/EEC. This paper describes the preservative efficacy of the well-known antimicrobial extracts of Lonicera caprifoleum and Lonicera japonica in combination with glyceryl caprylate and/or levulinic acid, p-anisic acid, and ethanol. We prepared a series of acidic (pH = 5.5) aqueous and O/W formulations, i.e., tonic lotion, shampoo, shower gel, conditioning cream, anticellulite cream, cleansing milk and peeling cream, containing (0.2% w/w) Lonicera extracts, alone in the case of tonic lotion and in combination with (1% w/w) glyceryl caprylate in the other products, and we performed challenge tests according to the European Pharmacopoeia procedures and criteria. Formulations such as shampoo, shower gel, and conditioning cream fulfilled criterion A, while tonic lotion, anticellulite cream, cleansing milk, and peeling cream fulfilled criterion B, in regard to contamination from A. niger. Furthermore, we evaluated the efficacy of the antimicrobial systems in two states of use: the intact product and after three weeks of consumer use. The results showed that A. niger was also detected during use by consumers in the products that satisfied only criterion B in challenge tests. The addition of antimicrobial fragrance ingredients such (safe during use. The small quantity (5% w/w) of ethanol gave an important assistance in order to boost the self-preserving system and to produce stable and safe products.

  8. The importance of Resilience to Primary Care Practitioners: an Interactive Psycho-Social Model

    Directory of Open Access Journals (Sweden)

    Dr Robert Muller

    2009-01-01

    Full Text Available In this paper, it is argued that an understanding of the factors that make up resilience canenhance communication and concordance between practitioner and patient. A model ispresented demonstrating that resilience is an interaction between factors in the internaldomain, comprising psychological characteristics and resources, and the external domain,comprising the social environment surrounding the individual. As resilience manifests itselfin different ways across the life-cycle, and according to individual circumstances, time is alsoan important part of the model presented in this paper. Understanding this model of resiliencecan lead to an insight that there are factors that can be influenced whereby the primary carepractitioner can treat the patient, or refer them after a process of concordance through adeeper understanding of the factors that surround a patient’s current health status. Underlyingthe model is the view that resilience is linked to the assets model of health, seeking topromote and maintain health and prevent illness. Therefore, primary care practitioners,through a deeper understanding of the circumstances of the patient, and throughunderstanding the factors that promote resilience, may be better able to take action in healthpromotion and maintenance.

  9. Assessing the importance of demographic parameters for population dynamics using Bayesian integrated population modeling.

    Science.gov (United States)

    Eacker, Daniel R; Lukacs, Paul M; Proffitt, Kelly M; Hebblewhite, Mark

    2017-06-01

    To successfully respond to changing habitat, climate or harvest, managers need to identify the most effective strategies to reverse population trends of declining species and/or manage harvest of game species. A classic approach in conservation biology for the last two decades has been the use of matrix population models to determine the most important vital rates affecting population growth rate (λ), that is, sensitivity. Ecologists quickly realized the critical role of environmental variability in vital rates affecting λ by developing approaches such as life-stage simulation analysis (LSA) that account for both sensitivity and variability of a vital rate. These LSA methods used matrix-population modeling and Monte Carlo simulation methods, but faced challenges in integrating data from different sources, disentangling process and sampling variation, and in their flexibility. Here, we developed a Bayesian integrated population model (IPM) for two populations of a large herbivore, elk (Cervus canadensis) in Montana, USA. We then extended the IPM to evaluate sensitivity in a Bayesian framework. We integrated known-fate survival data from radio-marked adults and juveniles, fecundity data, and population counts in a hierarchical population model that explicitly accounted for process and sampling variance. Next, we tested the prevailing paradigm in large herbivore population ecology that juvenile survival of neonates modeling in a Bayesian framework can provide multiple advantages. Our Bayesian LSA framework will provide a useful approach to addressing conservation challenges across a variety of species and data types. © 2017 by the Ecological Society of America.

  10. Forty years of 90Sr in situ migration: importance of soil characterization in modeling transport phenomena.

    Science.gov (United States)

    Fernandez, J M; Piault, E; Macouillard, D; Juncos, C

    2006-01-01

    In 1960 experiments were carried out on the transfer of (90)Sr between soil, grapes and wine. The experiments were conducted in situ on a piece of land limited by two control strips. The (90)Sr migration over the last 40 years was studied by performing radiological and physico-chemical characterizations of the soil on eight 70 cm deep cores. The vertical migration modeling of (90)Sr required the definition of a triple layer conceptual model integrating the rainwater infiltration at constant flux as the only external factor of influence. Afterwards the importance of a detailed soil characterization for modeling was discussed and satisfactory simulation of the (90)Sr vertical transport was obtained and showed a calculated migration rate of about 1.0 cm year(-1) in full agreement with the in situ measured values. The discussion was regarding some of the key parameters such as granulometry, organic matter content (in the Van Genuchten parameter determination), Kd and the efficient rainwater infiltration. Besides the experimental data, simplifying assumptions in modeling such as water-soil redistribution calculation and factual discontinuities in conceptual model were examined.

  11. Importance sampling for Lambda-coalescents in the infinitely many sites model

    CERN Document Server

    Birkner, Matthias; Steinruecken, Matthias; 10.1016/j.tpb.2011.01.005

    2011-01-01

    We present and discuss new importance sampling schemes for the approximate computation of the sample probability of observed genetic types in the infinitely many sites model from population genetics. More specifically, we extend the 'classical framework', where genealogies are assumed to be governed by Kingman's coalescent, to the more general class of Lambda-coalescents and develop further Hobolth et. al.'s (2008) idea of deriving importance sampling schemes based on 'compressed genetrees'. The resulting schemes extend earlier work by Griffiths and Tavar\\'e (1994), Stephens and Donnelly (2000), Birkner and Blath (2008) and Hobolth et. al. (2008). We conclude with a performance comparison of classical and new schemes for Beta- and Kingman coalescents.

  12. The importance of high spatial resolution for the performance of atmospheric chemistry-transport models

    Science.gov (United States)

    Mantzius Hansen, Kaj

    2010-05-01

    We have investigated the importance of spatial resolution for the performance of the Danish Eulerian Hemispheric Model (DEHM), a state-of-the-art atmospheric chemistry-transport model covering the majority of the Northern Hemisphere with a horizontal grid resolution of 150 km X 150 km. DEHM has 29 vertical layers in terrain-following sigma-coordinates extending up to a height of 100 hPa. Two-way nesting options with a nesting factor of three can be applied with higher resolution over a limited area of the model. At present the model can be run without nests or with one, two or three nests, each with resolutions of 50 km X 50 km, 16.7 km X 16.7 km, and 5.6 km X 5.6 km, respectively. The model includes a comprehensive chemistry scheme with more than 100 reactions and 67 atmospheric constituents, of which 4 relate to primary particulates (PM2.5, PM10, TSP and sea salt), other species are SOx, NOx, NHx, VOCs, and secondary inorganic particulates. DEHM is driven by meteorological data from the numerical weather prediction model MM5v3. Three simulations were performed with DEHM: one simulation with only the mother domain, one simulation with one nest over Europe, and one simulation with an additional nest covering Denmark and surrounding countries. All three simulations cover the period from 1989 to 2006. The predicted concentrations were evaluated against measurements from the EMEP monitoring network. Only sites within the innermost nest were included in the evaluation and the evaluations of the three simulations were compared to test the influence of spatial resolution on the performance of the model.

  13. Incorporating risk attitude into Markov-process decision models: importance for individual decision making.

    Science.gov (United States)

    Cher, D J; Miyamoto, J; Lenert, L A

    1997-01-01

    Most decision models published in the medical literature take a risk-neutral perspective. Under risk neutrality, the utility of a gamble is equivalent to its expected value and the marginal utility of living a given unit of time is the same regardless of when it occurs. Most patients, however, are not risk-neutral. Not only does risk aversion affect decision analyses when tradeoffs between short- and long-term survival are involved, it also affects the interpretation of time-tradeoff measures of health-state utility. The proportional time tradeoff under- or overestimates the disutility of an inferior health state, depending on whether the patient is risk-seeking or risk-averse (it is unbiased if the patient is risk-neutral). The authors review how risk attitude with respect to gambles for survival duration can be incorporated into decision models using the framework of risk-adjusted quality-adjusted life years (RA-QALYs). They present a simple extension of this framework that allows RA-QALYs to be calculated for Markov-process decision models. Using a previously published Markov-process model of surgical vs expectant treatment for benign prostatic hypertrophy (BPH), they show how attitude towards risk affects the expected number of QALYs calculated by the model. In this model, under risk neutrality, surgery was the preferred option. Under mild risk aversion, expectant treatment was the preferred option. Risk attitude is an important aspect of preferences that should be incorporated into decision models where one treatment option has upfront risks of morbidity or mortality.

  14. Representing ozone extremes in European megacities: the importance of resolution in a global chemistry climate model

    Directory of Open Access Journals (Sweden)

    Z. S. Stock

    2013-10-01

    Full Text Available The continuing growth of the world's urban population has led to an increasing number of cities with more than 10 million inhabitants. The higher emissions of pollutants, coupled to higher population density, makes predictions of air quality in these megacities of particular importance from both a science and a policy perspective. Global climate models are typically run at coarse resolution to enable both the efficient running of long time integrations, and the ability to run multiple future climate scenarios. However, when considering surface ozone concentrations at the local scale, coarse resolution can lead to inaccuracies arising from the highly non-linear ozone chemistry and the sensitivity of ozone to the distribution of its precursors on smaller scales. In this study, we use UM-UKCA, a global atmospheric chemistry model, coupled to the UK Met Office Unified Model, to investigate the impact of model resolution on tropospheric ozone, ranging from global to local scales. We focus on the model's ability to represent the probability of high ozone concentrations in the summer and low ozone concentrations, associated with polluted megacity environments, in the winter, and how this varies with horizontal resolution. We perform time-slice integrations with two model configurations at typical climate resolution (CR, ~150 km and at a higher resolution (HR, ~40 km. The CR configuration leads to overestimation of ozone concentrations on both regional and local scales, while it gives broadly similar results to the HR configuration on the global scale. The HR configuration is found to produce a more realistic diurnal cycle of ozone concentrations and to give a better representation of the probability density function of ozone values in urban areas such as the megacities of London and Paris. We discuss the possible causes for the observed difference in model behaviour between CR and HR configurations and estimate the relative contribution of chemical and

  15. Insertion of 3-D-primitives in mesh-based representations: towards compact models preserving the details.

    Science.gov (United States)

    Lafarge, Florent; Keriven, Renaud; Brédif, Mathieu

    2010-07-01

    We propose an original hybrid modeling process of urban scenes that represents 3-D models as a combination of mesh-based surfaces and geometric 3-D-primitives. Meshes describe details such as ornaments and statues, whereas 3-D-primitives code for regular shapes such as walls and columns. Starting from an 3-D-surface obtained by multiview stereo techniques, these primitives are inserted into the surface after being detected. This strategy allows the introduction of semantic knowledge, the simplification of the modeling, and even correction of errors generated by the acquisition process. We design a hierarchical approach exploring different scales of an observed scene. Each level consists first in segmenting the surface using a multilabel energy model optimized by -expansion and then in fitting 3-D-primitives such as planes, cylinders or tori on the obtained partition where relevant. Experiments on real meshes, depth maps and synthetic surfaces show good potential for the proposed approach.

  16. Understanding the relationship between Kano model's customer satisfaction scores and self-stated requirements importance.

    Science.gov (United States)

    Mkpojiogu, Emmanuel O C; Hashim, Nor Laily

    2016-01-01

    Customer satisfaction is the result of product quality and viability. The place of the perceived satisfaction of users/customers for a software product cannot be neglected especially in today competitive market environment as it drives the loyalty of customers and promotes high profitability and return on investment. Therefore understanding the importance of requirements as it is associated with the satisfaction of users/customers when their requirements are met is worth the pain considering. It is necessary to know the relationship between customer satisfactions when their requirements are met (or their dissatisfaction when their requirements are unmet) and the importance of such requirement. So many works have been carried out on customer satisfaction in connection with the importance of requirements but the relationship between customer satisfaction scores (coefficients) of the Kano model and users/customers self-stated requirements importance have not been sufficiently explored. In this study, an attempt is made to unravel the underlying relationship existing between Kano model's customer satisfaction indexes and users/customers self reported requirements importance. The results of the study indicate some interesting associations between these considered variables. These bivariate associations reveal that customer satisfaction index (SI), and average satisfaction coefficient (ASC) and customer dissatisfaction index (DI) and average satisfaction coefficient (ASC) are highly correlated (r = 96 %) and thus ASC can be used in place of either SI or DI in representing customer satisfaction scores. Also, these Kano model's customer satisfaction variables (SI, DI, and ASC) are each associated with self-stated requirements importance (IMP). Further analysis indicates that the value customers or users place on requirements that are met or on features that are incorporated into a product influences the level of satisfaction such customers derive from the product. The

  17. Importance of the Hydrogen Isocyanide Isomer in Modeling Hydrogen Cyanide Oxidation in Combustion

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul

    2017-01-01

    Hydrogen isocyanide (HNC) has been proposed as an important intermediate in oxidation of hydrogen cyanide (HCN) in combustion, but details of its chemistry are still in discussion. At higher temperatures, HCN and HNC equilibrate rapidly, and being more reactive than HCN, HNC offers a fast...... alternative route of oxidation for cyanides. However, in previous modeling, it has been required to omit the HNC subset partly or fully in the reaction mechanisms to obtain satisfactory predictions. In the present work, we re-examine the chemistry of HNC and its role in combustion nitrogen chemistry. The HNC...

  18. Use of a professional practice model to illuminate the importance of relationships.

    Science.gov (United States)

    Johnson, Linda; Ezekielian, Jamie

    2014-01-01

    At the Ohio State University Comprehensive Cancer Center-James Cancer Hospital and Solove Research Institute (OSUCCC-James), implementation of relationship-based care (RBC) and primary nursing (PN) along with enculturation of the James Nursing professional practice model (PPM), have improved patient and nurse satisfaction. This article describes the importance of relationships with self, colleagues, patients and families, and the community. Best practices and outcomes are shared to inspire others who seek to transform professional practice environments and organizational cultures by focusing on patients and families and engaging frontline leaders in the change process.

  19. Mass preserving image registration

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin Chien Pau

    2010-01-01

    The paper presents results the mass preserving image registration method in the Evaluation of Methods for Pulmonary Image Registration 2010 (EMPIRE10) Challenge. The mass preserving image registration algorithm was applied to the 20 image pairs. Registration was evaluated using four different...

  20. Modeling treatment couches in the Pinnacle treatment planning system: Especially important for arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Duggar, William Neil, E-mail: wduggar@umc.edu [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Nguyen, Alex [Ironwood Cancer and Research Center, Chandler, AZ (United States); Stanford, Jason; Morris, Bart; Yang, Claus C. [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States)

    2016-04-01

    This study is to demonstrate the importance and a method of properly modeling the treatment couch for dose calculation in patient treatment using arc therapy. The 2 treatment couch tops—Aktina AK550 and Elekta iBEAM evo—of Elekta LINACs were scanned using Philips Brilliance Big Bore CT Simulator. Various parts of the couch tops were contoured, and their densities were measured and recorded on the Pinnacle treatment planning system (TPS) using the established computed tomography density table. These contours were saved as organ models to be placed beneath the patient during planning. Relative attenuation measurements were performed following procedures outlined by TG-176 as well as absolute dose comparison of static fields of 10 × 10 cm{sup 2} that were delivered through the couch tops with that calculated in the TPS with the couch models. A total of 10 random arc therapy treatment plans (5 volumetric-modulated arc therapy [VMAT] and 5 stereotactic body radiation therapy [SBRT]), using 24 beams, were selected for this study. All selected plans were calculated with and without couch modeling. Each beam was evaluated using the Delta{sup 4} dosimetry system (Delta{sup 4}). The Student t-test was used to determine statistical significance. Independent reviews were exploited as per the Imaging and Radiation Oncology Core head and neck credentialing phantom. The selected plans were calculated on the actual patient anatomies with and without couch modeling to determine potential clinical effects. Large relative beam attenuations were noted dependent on which part of the couch top beams were passing through. Substantial improvements were also noted for static fields both calculated with the TPS and delivered physically when the couch models were included in the calculation. A statistically significant increase in agreement was noted for dose difference, distance to agreement, and γ-analysis with the Delta{sup 4} on VMAT and SBRT plans. A credentialing review showed

  1. Statistical Combination of Several Important Standard Model Higgs Boson Search Channels.

    CERN Document Server

    The ATLAS collaboration

    2009-01-01

    In this note we describe statistical procedures for combination of results from independent searches for the Higgs boson. Here only the Standard Model Higgs is considered, although the methods can easily be extended to non-standard Higgs models as well as to other searches. The methods are applied to Monte Carlo studies of four important search channels: H to tau+ tau-, H to W+ W- to e-nu mu-nu, H to gamma gamma, and H to ZZ)(*) to 4 leptons. The statistical treatment relies on a large sample approximation that is expected to be valid for an integrated luminosity of at least 2 fb-1 . Results are presented for the expected statistical significance of discovery and expected exclusion limits.

  2. Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution

    DEFF Research Database (Denmark)

    Kiil, Søren; Johnsson, Jan Erik; Dam-Johansen, Kim

    1999-01-01

    In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools...... suspended in a liquid solution. The measured PSDs were sensitive to the addition of a dispersing agent, the dispersion time, and the presence of ultrasound. It was found that the different PSDs influenced the simulated rate of dis-solution significantly (i.e. from below to above the measured dissolution...... rate). The results of this work show that a representative PSD is essential in order to model the rate of dissolution of lime-stone particles accurately....

  3. Model reduction algorithms for optimal control and importance sampling of diffusions

    Science.gov (United States)

    Hartmann, Carsten; Schütte, Christof; Zhang, Wei

    2016-08-01

    We propose numerical algorithms for solving optimal control and importance sampling problems based on simplified models. The algorithms combine model reduction techniques for multiscale diffusions and stochastic optimization tools, with the aim of reducing the original, possibly high-dimensional problem to a lower dimensional representation of the dynamics, in which only a few relevant degrees of freedom are controlled or biased. Specifically, we study situations in which either a reaction coordinate onto which the dynamics can be projected is known, or situations in which the dynamics shows strongly localized behavior in the small noise regime. No explicit assumptions about small parameters or scale separation have to be made. We illustrate the approach with simple, but paradigmatic numerical examples.

  4. MODELING THE DETERMINANTS OF EXPORTS AND IMPORTS: ASSESSMENT OF THE MACEDONIAN COMPETITIVE PERFORMANCES

    Directory of Open Access Journals (Sweden)

    Goce PETRESKI

    2009-01-01

    Full Text Available So far Macedonia has undergone an unsuccessful attempt to transition,distinguished by low growth rates, high unemployment, extensive poverty,balance of payments unfavorable position, technological lag etc. The externalsector, as a core element to growth perspectives of a small open economy iscritically dependant upon the export competitiveness. Consequently, thispaper will address some critical points of the Macedonian economy,particularly the vulnerability of the external sector alongside with the priceand trade liberalization. The set of analyses is to be carried out to explore theforeign trade structure, current account developments, as well as the majoraspects of qualitative competitiveness. In addition, we have examined theimpact of macroeconomic variables on exports and imports within theselected timeframe. We have therefore applied a comprehensive approach ofdynamic modeling based upon a vector - autoregression model determinedto control for endogeneity and set to estimate the long - run equilibriumrelations, as well as the short-run dynamics of the key variables.

  5. Rhizosphere Processes Are Quantitatively Important Components of Terrestrial Biogeochemical Cycles: Data & Models

    Science.gov (United States)

    Finzi, A.

    2016-12-01

    The rhizosphere is a hot spot and hot moment for biogeochemical cycles. Microbial activity, extracellular enzyme activity and element cycles are greatly enhanced by root derived carbon inputs. As such the rhizosphere may be an important driver of ecosystem responses to global changes such as rising temperatures and atmospheric CO2 concentrations. Empirical research on the rhizosphere is extensive but extrapolation of rhizosphere processes to large spatial and temporal scales is largely uninterrogated. Using a combination of field studies, meta-analysis and numerical models we have found good reason to think that scaling is possible. In this talk I discuss the results of this research and focus on the results of a new modeling effort that explicitly links root distribution and architecture with a model of microbial physiology to assess the extent to which rhizosphere processes may affect ecosystem responses to global change. Results to date suggest that root inputs of C and possibly nutrients (ie, nitrogen) impact the fate of new C inputs to the soil (ie, accumulation or loss) in response to warming and enhanced productivity at elevated CO2. The model also provides qualitative guidance on incorporating the known effects of ectomycorrhizal fungi on decomposition and rates of soil C and N cycling.

  6. Reply to Comment on "Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model"

    Energy Technology Data Exchange (ETDEWEB)

    Roth, R; Navratil, P

    2008-01-04

    In their comment on our recent Letter [1] Dean et al. [2] criticize the calculations for the ground-state energy of {sup 40}Ca within the importance truncated no-core shell model (NCSM). In particular they address the role of configurations beyond the 3p3h level, which have not been included in the {sup 40}Ca calculations for large N{sub max} {h_bar}{Omega} model spaces. Before responding to this point, the following general statements are in order. For the atomic nucleus as a self-bound system, translational invariance is an important symmetry. The only possibility to preserve translational invariance when working with a Slater determinant basis is to use the harmonic oscillator (HO) basis in conjunction with a basis truncation according to the total HO excitation energy, i.e. N{sub max} {h_bar}{Omega}, as done in the ab initio NCSM. This is important not only for obtaining proper binding or excitation energies, but also for a correct extraction of physical wavefunctions. The spurious center-of-mass components can be exactly removed only if the HO basis and the N{sub max} {h_bar}{Omega} truncation are employed. The minimal violation of the translational invariance was one of the main motivations for developing the importance-truncation scheme introduced in the Letter. In this scheme, we start with the complete N{sub max} {h_bar}{Omega} HO basis space and select important configurations via perturbation theory. All symmetries are under control and our importance-truncated NCSM calculations are completely variational and provide an upper bound of the ground-state energy of the system. The restriction to the 3p3h level, made for computational reasons in the N{sub max} > 8 calculations for {sup 40}Ca, is not inherent to the importance truncation scheme. The explicit inclusion of 4p4h configurations--though computationally more demanding--is straight-forward, even for the largest N{sub max} {h_bar}{Omega} model spaces discussed. To demonstrate this fact we have

  7. Hitting the moving target: modelling ontogenetic shifts with stable isotopes reveals the importance of isotopic turnover.

    Science.gov (United States)

    Hertz, Eric; Trudel, Marc; El-Sabaawi, Rana; Tucker, Strahan; Dower, John F; Beacham, Terry D; Edwards, Andrew M; Mazumder, Asit

    2016-05-01

    Ontogenetic niche shifts are widely prevalent in nature and are important in shaping the structure and dynamics of ecosystems. Stable isotope analysis is a powerful tool to assess these shifts, with δ(15) N providing a measure of trophic level and δ(13) C a measure of energy source. Previous applications of stable isotopes to study ontogenetic niche shifts have not considered the appreciable time lag between diet and consumer tissue associated with isotopic turnover. These time lags introduce significant complexity into field studies of ontogenetic niche shifts. Juvenile Chinook salmon (Oncorhynchus tshawytscha) migrate from freshwater to marine ecosystems and shift their diet from feeding primarily on invertebrates to feeding primarily on fish. This dual ontogenetic habitat and diet shift, in addition to the long time lag associated with isotopic turnover, suggests that there is potential for a disconnect between the prey sources that juvenile salmon are consuming, and the inferred prey sources from stable isotopes. We developed a model that considered ontogenetic niche shifts and time lags associated with isotopic turnover, and compared this 'ontogeny' model to one that considered only isotopic turnover. We used a Bayesian framework to explicitly account for parameter uncertainty. Data showed overwhelming support for the ontogeny model relative to the isotopic turnover model. Estimated variables from best model fits indicate that the ontogeny model predicts a much greater reliance on fish prey than does the stomach content data. Overall, we found that this method of quantifying ontogenetic niche shifts effectively accounted for both isotopic turnover and ontogenetic diet shifts; a finding that could be widely applicable to a variety of systems.

  8. An Efficient Context-Aware Privacy Preserving Approach for Smartphones

    Directory of Open Access Journals (Sweden)

    Lichen Zhang

    2017-01-01

    Full Text Available With the proliferation of smartphones and the usage of the smartphone apps, privacy preservation has become an important issue. The existing privacy preservation approaches for smartphones usually have less efficiency due to the absent consideration of the active defense policies and temporal correlations between contexts related to users. In this paper, through modeling the temporal correlations among contexts, we formalize the privacy preservation problem to an optimization problem and prove its correctness and the optimality through theoretical analysis. To further speed up the running time, we transform the original optimization problem to an approximate optimal problem, a linear programming problem. By resolving the linear programming problem, an efficient context-aware privacy preserving algorithm (CAPP is designed, which adopts active defense policy and decides how to release the current context of a user to maximize the level of quality of service (QoS of context-aware apps with privacy preservation. The conducted extensive simulations on real dataset demonstrate the improved performance of CAPP over other traditional approaches.

  9. Self-preserving cosmetics.

    Science.gov (United States)

    Varvaresou, A; Papageorgiou, S; Tsirivas, E; Protopapa, E; Kintziou, H; Kefala, V; Demetzos, C

    2009-06-01

    Preservatives are added to products for two reasons: first, to prevent microbial spoilage and therefore to prolong the shelf life of the product; second, to protect the consumer from a potential infection. Although chemical preservatives prevent microbial growth, their safety is questioned by a growing segment of consumers. Therefore, there is a considerable interest in the development of preservative-free or self-preserving cosmetics. In these formulations traditional/chemical preservatives have been replaced by other cosmetic ingredients with antimicrobial properties that are not legislated as preservatives according to the Annex VI of the Commission Directive 76/768/EEC and the amending directives (2003/15/EC, 2007/17/EC and 2007/22/EC). 'Hurdle Technology', a technology that has been used for the control of product safety in the food industry since 1970s, has also been applied for the production of self-preserving cosmetics. 'Hurdle Technology' is a term used to describe the intelligent combination of different preservation factors or hurdles to deteriorate the growth of microorganisms. Adherence to current good manufacturing practice, appropriate packaging, careful choice of the form of the emulsion, low water activity and low or high pH values are significant variables for the control of microbial growth in cosmetic formulations. This paper describes the application of the basic principles of 'Hurdle Technology' in the production of self-preserving cosmetics. Multifunctional antimicrobial ingredients and plant-derived essential oils and extracts that are used as alternative or natural preservatives and are not listed in Annex VI of the Cosmetic Directive are also reported.

  10. How important are the descriptions of vegetation in distributed hydrologic models?

    Science.gov (United States)

    Cuntz, Matthias; Thober, Stephan; Zink, Matthias; Rakovec, Oldrich; Samaniego, Luis

    2016-04-01

    The land surface transforms incoming, absorbed radiation into other energy forms and radiation with longer wavelengths. The land surface emits long-wave radiation, stores energy in the soil, the biomass and the air in the boundary layer, and exchanges sensible and latent heat with the atmosphere. The latter, latent heat consists of evaporation from the soil and canopy and transpiration by plants. Plants enhance in this picture the absorption of incoming radiation and decrease the resistance for evaporation of deeper soil water. Transpiration by plants is therefore either energy-limited by low incoming radiation or water-limited by small soil moisture. In the extreme cases, all available energy will be used for evapotranspiration in cold regions and all available water will be used for evapotranspiration in arid regions. Very simple formulations of latent heat, which include plant processes only very indirectly, work well in hydrologic models for these limiting cases. These simple formulations seem to work also surprisingly well in temperate regions. Hydrologic models have, however, considerable problems in semi-arid regions where the vegetation influence on latent heat should be largest. But the models have to deal with much more problems in these regions. For example data scarcity in the Mediterranean leads to very large model uncertainty due to the forcing data. Water supply is also often very regulated in semi-arid regions. Variability in river discharge can hence be largely driven by the anthropogenic influence rather than natural meteorological variations in these regions. Here we will show for Europe the areas and times when the descriptions of plant processes are important for hydrologic models. We will compare differences in model uncertainties that come from 1. different formulations of evapotranspiration, 2. different descriptions of soil-plant interactions, and 3. uncertainty in the model's input data. It can be seen that model uncertainty stemming from

  11. Understanding the Importance of Shape in Thermal Modeling: The Case of 1627 Ivar

    Science.gov (United States)

    Crowell, Jenna L.; Howell, Ellen S.; Magri, Christopher; Fernandez, Yanga R.; Nolan, Michael C.; Vervack, Ronald J., Jr.; Marshall, Sean E.

    2016-10-01

    We seek to investigate the compositional surface variation of near Earth asteroids (NEAs). To do this, we employ detailed shape models and near-IR observations, taken over a range of viewing geometries, in order to create thermophysical models. The thermal spectra are therefore linked to regions on the asteroid, and we can seek out a set of thermal parameters that are capable of reproducing the thermal spectra over the entirety of the asteroid's surface. This method also enables us to characterize portions of the asteroid that may have different thermal properties than other regions, in which case there is no single set of thermal parameters that satisfy all of the thermal observations, indicating a heterogeneous surface.We present our findings on 1627 Ivar, an Amor class NEA with a taxonomic type of Sqw [1], and a rotation period of 4.7951689 hr ± 0.0000026 [2]. During Ivar's apparition in 2013, we obtained CCD lightcurves, radar data, and near-IR spectra. Using the software SHAPE, we have used lightcurve and radar data to generate an improved shape model of Ivar [2][3].For the thermophysical modeling, we have used SHERMAN [3,4] to determine which reflective, thermal, and surface properties for Ivar best reproduce our spectra, taken using the SpeX instrument at the NASA IRTF [5]. Input parameters for SHERMAN include the asteroid's IR emissivity, optical scattering law and thermal inertia in order to complete thermal computations based on the shape model. We also compare these results to those created by using the Kaasalainen lightcurve model [6]. Since models created from lightcurve inversion techniques far outnumber those created using radar data, it is important to understand how these two models differ when studying thermal models.References: [1] DeMeo et al. 2009, Icarus 202, 160-180 [2] Crowell et al. 2016, Icarus, in press [3] Crowell et al. 2014, AAS/DPS 46 [4] Howell et al. 2015, AAS/DPS 47 [5] Rayner et al. 2003, PASP 115, 362 [6] Kaasalainen et al. 2004

  12. Donor pretreatment with carbamylated erythropoietin in a brain death model reduces inflammation more effectively than erythropoietin while preserving renal function

    NARCIS (Netherlands)

    Nijboer, Willemijn N.; Ottens, Petra J.; van Dijk, Antony; van Goor, Harry; Ploeg, Rutger J.; Leuvenink, Henri G. D.

    2010-01-01

    Objective: We hypothesized that donor treatment of deceased brain dead donors would lead to a decrease in inflammatory responses seen in brain death and lead to a restoration of kidney function. Design: A standardized slow-induction rat brain death model followed by evaluation of kidney function in

  13. Donor pretreatment with carbamylated erythropoietin in a brain death model reduces inflammation more effectively than erythropoietin while preserving renal function.

    NARCIS (Netherlands)

    Nijboer, W.N.; Ottens, P.J.; Dijk, A.P.J. van; Goor, H. van; Ploeg, R.J.; Leuvenink, H.G.

    2010-01-01

    OBJECTIVE: We hypothesized that donor treatment of deceased brain dead donors would lead to a decrease in inflammatory responses seen in brain death and lead to a restoration of kidney function. DESIGN: A standardized slow-induction rat brain death model followed by evaluation of kidney function in

  14. Sodium homeostasis is preserved in a global 11β-hydroxysteroid dehydrogenase type 1 knockout mouse model

    DEFF Research Database (Denmark)

    Christensen, Thorbjørn H; Bailey, Matthew A; Kenyon, Christopher J

    2015-01-01

    hypothesized that loss of renal 11βHSD1 would result in salt wasting and tested this in a knockout mouse model in which 11βHSD1 was deleted in all body tissues. In balance studies, 11βHSD1 deletion had no effect on water, sodium or potassium metabolism; transition to a low-sodium diet did not reveal...

  15. MODELING OF WORLD'S SYSTEMICALLY IMPORTANT ECONOMIES IMPACT ON THE DYNAMICS OF MACROECONOMIC INDICATORS IN UKRAINE

    Directory of Open Access Journals (Sweden)

    O. Bazhenova

    2015-03-01

    Full Text Available This paper develops the vector autoregression model of the Ukraine’s economy for exploring the dynamics of key indicators of the domestic economy in response to the shocks from systemically important economies. The foreign variables in the model are growth rates of real GDP, consumer price indices in the advanced economies and in countries of emerging and developing Asia and oil price. The results suggest that the shocks from the “large” economies are absorbed by the domestic economy for a long time. A significant part of the variability of real GDP growth index in Ukraine is due to external factors. Inflation in advanced countries has the most significant influence on this variability (among other external shocks that confirms inflation import from these economies. At the same time the price of oil does not significantly contribute to the explanation of the mentioned variability. Given the euro area share increase in foreign trade and China’s impact on metal market conditions this paper also explores the influence of these economies’ indicators (notably production indices and consumer price indices on Ukraine’s economy.

  16. Ecological niche models reveal the importance of climate variability for the biogeography of protosteloid amoebae.

    Science.gov (United States)

    Aguilar, María; Lado, Carlos

    2012-08-01

    Habitat availability and environmental preferences of species are among the most important factors in determining the success of dispersal processes and therefore in shaping the distribution of protists. We explored the differences in fundamental niches and potential distributions of an ecological guild of slime moulds-protosteloid amoebae-in the Iberian Peninsula. A large set of samples collected in a north-east to south-west transect of approximately 1000 km along the peninsula was used to test the hypothesis that, together with the existence of suitable microhabitats, climate conditions may determine the probability of survival of species. Although protosteloid amoebae share similar morphologies and life history strategies, canonical correspondence analyses showed that they have varied ecological optima, and that climate conditions have an important effect in niche differentiation. Maxent environmental niche models provided consistent predictions of the probability of presence of the species based on climate data, and they were used to generate maps of potential distribution in an 'everything is everywhere' scenario. The most important climatic factors were, in both analyses, variables that measure changes in conditions throughout the year, confirming that the alternation of fruiting bodies, cysts and amoeboid stages in the life cycles of protosteloid amoebae constitutes an advantage for surviving in a changing environment. Microhabitat affinity seems to be influenced by climatic conditions, which suggests that the micro-environment may vary at a local scale and change together with the external climate at a larger scale.

  17. Terminological and methodological aspects in investigating the preservation of rare library materials

    Directory of Open Access Journals (Sweden)

    Damir Hasenay

    2008-07-01

    efficient management and good organization of preservation presupposes a systematic and comprehensive approach applicable independent of the type of institution or type of material. The management and organization issues concerning the preservation of rare library materials is shown as an overview of their most important elements, with a critical evaluation of the most important achievements in theory in practice. The methodological aspect is also very important in investigating the preservation of rare library materials.The special emphasis is placed on the systematic investigation of the status of library holdings and the possibilities offered by the qualitative and quantitative description of holdings on the one hand, and the possibilities offered by the methods of interview and/or questionnaire on the other. Several practical examples that may serve as test models in the approach to this issue have been analyzed.The existing organization of the collection of historical newspapers from the city of Osijek area, and the organization of the collection of old books in the library of the Franciscan monastery in Mostar in relation to their status and protection activities have also been discussed. By comparing these models a significant difference in the material and content characteristics of the analyzed rare library holdings have been identified. This difference calls for the use of different methodologies for investigating the condition of the holdings. The information on the condition of the library holdings and approaches to their preservation serve as a starting point for planning further steps for the efficient preservation of rare library materials. The insights into the problem of preservation presented in this paper should be understood as a foundation for further implementation on similar examples.Key words : preservation of library materials, rare library materials, rare books, historical newspapers, organization and management of preservation, description of the

  18. The importance of data quality for generating reliable distribution models for rare, elusive, and cryptic species

    Science.gov (United States)

    Aubry, Keith B.; Raley, Catherine M.; McKelvey, Kevin S.

    2017-01-01

    The availability of spatially referenced environmental data and species occurrence records in online databases enable practitioners to easily generate species distribution models (SDMs) for a broad array of taxa. Such databases often include occurrence records of unknown reliability, yet little information is available on the influence of data quality on SDMs generated for rare, elusive, and cryptic species that are prone to misidentification in the field. We investigated this question for the fisher (Pekania pennanti), a forest carnivore of conservation concern in the Pacific States that is often confused with the more common Pacific marten (Martes caurina). Fisher occurrence records supported by physical evidence (verifiable records) were available from a limited area, whereas occurrence records of unknown quality (unscreened records) were available from throughout the fisher’s historical range. We reserved 20% of the verifiable records to use as a test sample for both models and generated SDMs with each dataset using Maxent. The verifiable model performed substantially better than the unscreened model based on multiple metrics including AUCtest values (0.78 and 0.62, respectively), evaluation of training and test gains, and statistical tests of how well each model predicted test localities. In addition, the verifiable model was consistent with our knowledge of the fisher’s habitat relations and potential distribution, whereas the unscreened model indicated a much broader area of high-quality habitat (indices > 0.5) that included large expanses of high-elevation habitat that fishers do not occupy. Because Pacific martens remain relatively common in upper elevation habitats in the Cascade Range and Sierra Nevada, the SDM based on unscreened records likely reflects primarily a conflation of marten and fisher habitat. Consequently, accurate identifications are far more important than the spatial extent of occurrence records for generating reliable SDMs for the

  19. The importance of volumetric canopy morphology when modelling drag around riparian vegetation

    Science.gov (United States)

    Boothroyd, Richard; Hardy, Richard; Warburton, Jeff; Marjoribanks, Timothy

    2017-04-01

    Riparian vegetation has a significant impact on the hydraulic functioning of river systems. The bulk of past work concerned with modelling the influence of vegetation on flow has considered vegetation to be morphologically simple, and has generally neglected the complexity and porosity of natural plants, defined herein as the volumetric canopy morphology. However, the volumetric canopy morphology can influence the mean and turbulent properties of the flow, producing spatially heterogeneous downstream velocity fields. By explicitly accounting for this in a computational fluid dynamics (CFD) model, and representing the plant as a porous blockage, complex flow structures and drag can be modelled. For a riparian species, Hebe odora, good agreement with flume measurements are found. Plant shear layer turbulence is shown to be dominated by Kelvin-Helmholtz and Görtler-type vortices, generated through shear instability. Porous representations of the plants, that allow for flow to pass through the plant canopy interior, are compared against fully impermeable plant representations. Penetration of fluid through the canopy in the porous case resembles 'bleed-flow', and this results in a plant wake region that significantly differs from the impermeable case, which is characteristic of wake flow around a traditional bluff body. These results demonstrate the significant effect that the volumetric canopy morphology and porosity of natural plants has on the three-dimensional flow and in-stream drag, and enables a re-evaluation of vegetative flow resistance. The modelled results allow a species dependent Manning's n to be calculated, and this presents an opportunity to move away from the conventional methods of representing vegetation in hydraulic models, in favour of a more physically determined approach. Given the importance of vegetation in river corridor management, and the increasing application of UAV imagery to map riparian vegetation, the numerical scheme developed here

  20. How important is heterogeneous parameter distribution in capturing the catchment response through hydrologic modelling?

    Science.gov (United States)

    Devak, Manjula; Dhanya, Ct

    2017-04-01

    The scrupulous selection of critical spatial and temporal resolution and the evaluation of optimum values for various model parameters are essential aspects in any hydrological modelling study. The accurate assessment of various model parameters is vitally important for the detailed and complete representation of the various physical processes illustrating land-atmosphere interaction. Studies in the past have taken up various auto-calibration and parameter transferability schemes to address these; but the heterogeneity of calibration parameters across grids is greatly ignored often. In many studies, heterogeneity is often compromised through the usual interpolation approaches adopted across grids. In the present study, we focus to analyze the response of a catchment by adopting a heterogeneous and homogeneous parameter distribution in the hydrological model. The semi-distributed hydrological model, Variable Infiltration Capacity (VIC-3L) model, which offers sub-grid variability in soil moisture storage capacity and vegetation classes, is used for this comparison. Nine model parameters are selected for calibrating the VIC-3L model, namely variable infiltration curve parameter (infilt), maximum velocity of base flow for each grid cells (DSmax), fraction of DSmax where non-linear base flow begins (DS, fraction of maximum soil moisture where non-linear base flow occurs (WS), depth of 2nd soil layer (D2), depth of 3rd soil layer (D3), exponent used in baseflow curve (c), advection coefficient (C) and diffusion coefficient (D). Latin-Hypercube sampling is adopted to sample these nine parameters. In homogenous approach, the traditional way of constant soil parameter distribution (HoSCP) is adopted to prepare the parameter set. While, in heterogeneous approach, grid-to-grid variability is ensured by constructing a Heterogeneous Soil Calibration Parameter (HeSCP) set through systematic sampling of already sampled set. The sampling size is made equal to the number of grids

  1. The nature of blast-wave-driven interfacial instabilities - important implications for modeling supernovae explosions

    Science.gov (United States)

    Miles, Aaron

    2004-11-01

    In this talk we discuss the nature of late-time, broad-banded instability development at an interface when a strong blast wave travels from a heavier to lighter fluid, as is the case in a supernova explosion. After a short period of Richtmyer-Meshkov growth, the interface is unstable via the Rayleigh-Taylor mechanism, which rapidly becomes the dominant energy source for growth. This situation is distinct from the classical case in two important ways, both of which can be understood in terms of a bubble merger model we have developed for blast-wave-driven systems. Rather than the constant acceleration feeding the instability to spawn ever larger scales and accelerate the growth, the decaying acceleration in the blast-wave case leads to a decay in the RT growth rate, and a freezing in of a preferred largest scale, which is dependent on the precise details of the system. In the language of bubble-merger models, this can be understood in terms of the time for the generation of the next largest scale being longer than the lifetime of the blast wave. Secondly, the continual expansion behind the blast front precludes the emergence of a self-similar regime, independent of the initial conditions, in the planar case. Self-similarity may be recovered in diverging systems but may be difficult to observe in reality because of rather restrictive conditions that must be met. These observations are borne out by hi-resolution numerical simulations using the higher order Godunov AMR hydrocode Raptor in 2 and 3D, and explain other simulations of instability growth in supernovae explosions; the initial "interfacial" structure is likely very important in determining the late-time growth. The model predictions are also consistent with numerous images of natural and manmade explosions.

  2. Research on the Stability of a Rabbit Dry Eye Model Induced by Topical Application of the Preservative Benzalkonium Chloride

    Science.gov (United States)

    Luan, Shaohong; Wan, Pengxia; Li, Naiyang; Tang, Jing; Han, Yu; Xiong, Cuiju; Wang, Zhichong

    2012-01-01

    Background Dry eye is a common disease worldwide, and animal models are critical for the study of it. At present, there is no research about the stability of the extant animal models, which may have negative implications for previous dry eye studies. In this study, we observed the stability of a rabbit dry eye model induced by the topical benzalkonium chloride (BAC) and determined the valid time of this model. Methods and Findings Eighty white rabbits were randomly divided into four groups. One eye from each rabbit was randomly chosen to receive topical 0.1% BAC twice daily for 2 weeks (Group BAC-W2), 3 weeks (Group BAC-W3), 4 weeks (Group BAC-W4), or 5 weeks (Group BAC-W5). Fluorescein staining, Schirmer's tests, and conjunctival impression cytology were performed before BAC treatment (normal) and on days 0, 7, 14 and 21 after BAC removal. The eyeballs were collected at these time points for immunofluorescence staining, hematoxylin and eosin (HE) staining, and electron microscopy. After removing BAC, the signs of dry eye in Group BAC-W2 lasted one week. Compared with normal, there were still significant differences in the results of Schirmer's tests and fluorescein staining in Groups BAC-W3 and BAC-W4 on day 7 (P<0.05) and in Group BAC-W5 on day 14 (P<0.05). Decreases in goblet cell density remained stable in the three experimental groups at all time points (P<0.001). Decreased levels of mucin-5 subtype AC (MUC5AC), along with histopathological and ultrastructural disorders of the cornea and conjunctiva could be observed in Group BAC-W4 and particularly in Group BAC-W5 until day 21. Conclusions A stable rabbit dry eye model was induced by topical 0.1% BAC for 5 weeks, and after BAC removal, the signs of dry eye were sustained for 2 weeks (for the mixed type of dry eye) or for at least 3 weeks (for mucin-deficient dry eye). PMID:22438984

  3. Research on the stability of a rabbit dry eye model induced by topical application of the preservative benzalkonium chloride.

    Directory of Open Access Journals (Sweden)

    Chaoyang Li

    Full Text Available BACKGROUND: Dry eye is a common disease worldwide, and animal models are critical for the study of it. At present, there is no research about the stability of the extant animal models, which may have negative implications for previous dry eye studies. In this study, we observed the stability of a rabbit dry eye model induced by the topical benzalkonium chloride (BAC and determined the valid time of this model. METHODS AND FINDINGS: Eighty white rabbits were randomly divided into four groups. One eye from each rabbit was randomly chosen to receive topical 0.1% BAC twice daily for 2 weeks (Group BAC-W2, 3 weeks (Group BAC-W3, 4 weeks (Group BAC-W4, or 5 weeks (Group BAC-W5. Fluorescein staining, Schirmer's tests, and conjunctival impression cytology were performed before BAC treatment (normal and on days 0, 7, 14 and 21 after BAC removal. The eyeballs were collected at these time points for immunofluorescence staining, hematoxylin and eosin (HE staining, and electron microscopy. After removing BAC, the signs of dry eye in Group BAC-W2 lasted one week. Compared with normal, there were still significant differences in the results of Schirmer's tests and fluorescein staining in Groups BAC-W3 and BAC-W4 on day 7 (P<0.05 and in Group BAC-W5 on day 14 (P<0.05. Decreases in goblet cell density remained stable in the three experimental groups at all time points (P<0.001. Decreased levels of mucin-5 subtype AC (MUC5AC, along with histopathological and ultrastructural disorders of the cornea and conjunctiva could be observed in Group BAC-W4 and particularly in Group BAC-W5 until day 21. CONCLUSIONS: A stable rabbit dry eye model was induced by topical 0.1% BAC for 5 weeks, and after BAC removal, the signs of dry eye were sustained for 2 weeks (for the mixed type of dry eye or for at least 3 weeks (for mucin-deficient dry eye.

  4. The importance of spatial ability and mental models in learning anatomy

    Science.gov (United States)

    Chatterjee, Allison K.

    As a foundational course in medical education, gross anatomy serves to orient medical and veterinary students to the complex three-dimensional nature of the structures within the body. Understanding such spatial relationships is both fundamental and crucial for achievement in gross anatomy courses, and is essential for success as a practicing professional. Many things contribute to learning spatial relationships; this project focuses on a few key elements: (1) the type of multimedia resources, particularly computer-aided instructional (CAI) resources, medical students used to study and learn; (2) the influence of spatial ability on medical and veterinary students' gross anatomy grades and their mental models; and (3) how medical and veterinary students think about anatomy and describe the features of their mental models to represent what they know about anatomical structures. The use of computer-aided instruction (CAI) by gross anatomy students at Indiana University School of Medicine (IUSM) was assessed through a questionnaire distributed to the regional centers of the IUSM. Students reported using internet browsing, PowerPoint presentation software, and email on a daily bases to study gross anatomy. This study reveals that first-year medical students at the IUSM make limited use of CAI to study gross anatomy. Such studies emphasize the importance of examining students' use of CAI to study gross anatomy prior to development and integration of electronic media into the curriculum and they may be important in future decisions regarding the development of alternative learning resources. In order to determine how students think about anatomical relationships and describe the features of their mental models, personal interviews were conducted with select students based on students' ROT scores. Five typologies of the characteristics of students' mental models were identified and described: spatial thinking, kinesthetic approach, identification of anatomical structures

  5. Toward sustainable material usage: evaluating the importance of market motivated agency in modeling material flows.

    Science.gov (United States)

    Gaustad, Gabrielle; Olivetti, Elsa; Kirchain, Randolph

    2011-05-01

    Increasing recycling will be a key strategy for moving toward sustainable materials usage. There are many barriers to increasing recycling, including quality issues in the scrap stream. Repeated recycling can compound this problem through the accumulation of tramp elements over time. This paper explores the importance of capturing recycler decision-making in accurately modeling accumulation and the value of technologies intended to mitigate it. A method was developed combining dynamic material flow analysis with allocation of those materials into production portfolios using blending models. Using this methodology, three scrap allocation methods were explored in the context of a case study of aluminum use: scrap pooling, pseudoclosed loop, and market-based. Results from this case analysis suggest that market-driven decisions and upgrading technologies can partially mitigate the negative impact of accumulation on scrap utilization, thereby increasing scrap use and reducing greenhouse gas emissions. A market-based allocation method for modeling material flows suggests a higher value for upgrading strategies compared to a pseudoclosed loop or pooling allocation method for the scenarios explored.

  6. The Importance of Materials Data and Modelling Parameters in an FE Simulation of Linear Friction Welding

    Directory of Open Access Journals (Sweden)

    R. Turner

    2014-01-01

    Full Text Available Linear friction welding has become a key technology in the aeroengine industry due to its capability to produce blisk components. Finite element (FE simulation of linear friction welding applications has been studied in recent years by a number of institutions, using a variety of software codes. Several codes have been demonstrated to be capable of predicting with reasonable accuracy some or all of the critical outputs of friction welding, namely, the thermal loading, plastic deformation, and residual stresses generated. The importance of reliable material data in performing these calculations is paramount. Available material data in the published literature is often restricted to lower temperatures and strain rate regimes. Extrapolation methods used on this data to estimate high temperature properties can lead to uncertainties in the modelled predictions. This paper reviews the approach to materials modelling, including material datasets and material constitutive laws, for FE simulation work in the literature regarding linear friction welding. Best-practice methods for materials constitutive laws, materials data-sets, and the associated experimental temperatures and strain rates used to gather data are suggested. Finally, successfully validated modelled outcomes—when a robust, reliable, and accurate material database has been selected—are demonstrated for a number of the FE methods considered.

  7. Package Formats for Preserved Digital Material

    DEFF Research Database (Denmark)

    Zierau, Eld

    2012-01-01

    This paper presents an investigation of the best suitable package formats for long term digital preservation. The choice of a package format for preservation is crucial for future access, thus a thorough analysis of choice is important. The investigation presented here covers setting up requireme......This paper presents an investigation of the best suitable package formats for long term digital preservation. The choice of a package format for preservation is crucial for future access, thus a thorough analysis of choice is important. The investigation presented here covers setting up...... the listed requirements will ensure mitigating a number of risks of information loss. Thus WARC is the best choice for a package format in cases where these same risks are judged most important. Similar analysis will need to be carried out in cases where the requirements differ from the ones described here...

  8. Overexpression of mitochondrial oxodicarboxylate carrier (ODC1 preserves oxidative phosphorylation in a yeast model of Barth syndrome

    Directory of Open Access Journals (Sweden)

    Maxence de Taffin de Tilques

    2017-04-01

    Full Text Available Cardiolipin (CL is a diglycerol phospholipid mostly found in mitochondria where it optimizes numerous processes, including oxidative phosphorylation (OXPHOS. To function properly, CL needs to be unsaturated, which requires the acyltransferase tafazzin. Loss-of-function mutations in this protein are responsible for Barth syndrome (BTHS, presumably because of a diminished OXPHOS capacity. Here, we show that overexpressing Odc1p, a conserved oxodicarboxylic acid carrier located in the mitochondrial inner membrane, fully restores oxidative phosphorylation in a yeast model (taz1Δ of BTHS. The rescuing activity involves the recovery of normal expression of key components that sustain oxidative phosphorylation, including cytochrome c and electron transport chain complexes IV and III, which are strongly downregulated in taz1Δ yeast. Interestingly, overexpression of Odc1p was also shown previously to rescue yeast models of mitochondrial diseases caused by defects in the assembly of ATP synthase and by mutations in the MPV17 protein that result in hepatocerebral mitochondrial DNA depletion syndrome. These findings define the transport of oxodicarboxylic acids across the inner membrane as a potential therapeutic target for a large spectrum of mitochondrial diseases, including BTHS.

  9. The role of spatial information in the preservation of the shrimp nursery function of mangroves: a spatially explicit bio-economic model for the assessment of land use trade-offs.

    Science.gov (United States)

    Zavalloni, Matteo; Groeneveld, Rolf A; van Zwieten, Paul A M

    2014-10-01

    Conversion to aquaculture affects the provision of important ecosystem services provided by mangrove ecosystems, and this effect depends strongly on the location of the conversion. We introduce in a bio-economic mathematical programming model relevant spatial elements that affect the provision of the nursery habitat service of mangroves: (1) direct or indirect connection of mangroves to watercourses; (2) the spatial allocation of aquaculture ponds; and (3) the presence of non-linear relations between mangrove extent and juvenile recruitment to wild shrimp populations. By tracing out the production possibilities frontier of wild and cultivated shrimp, the model assesses the role of spatial information in the trade-off between aquaculture and the nursery habitat function using spatial elements relevant to our model of a mangrove area in Ca Mau Province, Viet Nam. Results show that where mangrove forests have to coexist with shrimp aquaculture ponds, the inclusion of specific spatial information on ecosystem functions in considerations of land allocation can achieve aquaculture benefits while largely preserving the economic benefits generated by the nursery habitat function. However, if spatial criteria are ignored, ill-advised land allocation decisions can easily lead to a collapse of the mangrove's nursery function.

  10. The importance of the Non Obese Diabetic (NOD) mouse model in autoimmune diabetes.

    Science.gov (United States)

    Pearson, James A; Wong, F Susan; Wen, Li

    2016-01-01

    Type 1 Diabetes (T1D) is an autoimmune disease characterized by the pancreatic infiltration of immune cells resulting in T cell-mediated destruction of the insulin-producing beta cells. The successes of the Non-Obese Diabetic (NOD) mouse model have come in multiple forms including identifying key genetic and environmental risk factors e.g. Idd loci and effects of microorganisms including the gut microbiota, respectively, and how they may contribute to disease susceptibility and pathogenesis. Furthermore, the NOD model also provides insights into the roles of the innate immune cells as well as the B cells in contributing to the T cell-mediated disease. Unlike many autoimmune disease models, the NOD mouse develops spontaneous disease and has many similarities to human T1D. Through exploiting these similarities many targets have been identified for immune-intervention strategies. Although many of these immunotherapies did not have a significant impact on human T1D, they have been shown to be effective in the NOD mouse in early stage disease, which is not equivalent to trials in newly-diagnosed patients with diabetes. However, the continued development of humanized NOD mice would enable further clinical developments, bringing T1D research to a new translational level. Therefore, it is the aim of this review to discuss the importance of the NOD model in identifying the roles of the innate immune system and the interaction with the gut microbiota in modifying diabetes susceptibility. In addition, the role of the B cells will also be discussed with new insights gained through B cell depletion experiments and the impact on translational developments. Finally, this review will also discuss the future of the NOD mouse and the development of humanized NOD mice, providing novel insights into human T1D.

  11. DIAGNOSIS IMPORTANCE OF RURAL DEVELOPMENT OF A MODEL AGROFORESTAL IN PEASANT COMMUNITIES OF SIERRA DE HUAUTLA

    Directory of Open Access Journals (Sweden)

    Miguel Uribe-Gómez

    2015-07-01

    Full Text Available Family agricultural is socioeconomically important in rural areas, but in Mexico, from the 80's this production system presents social stagnation. This type of agriculture presents a dynamic reality in the interests of each producer and limiting access to factors of production (land, labor and capital. In this investigation a methodology for analysis and diagnosis of production systems in rural areas, in two communities in the Country Sierra de Huautla Tepalcingo, Morelos, Mexico was applied. The proposal is based on an assessment of the environmental, historical, technological and socio-economic assessment of different productive activities for different types of units Family Production of the communities studied. The study showed that 40% of Family Production Units fail to exceed the threshold of survival and show impossibility capitalization medium and long term. So it is advisable to implement a model of local agricultural development to improve the socioeconomic conditions of Family Production Units of peasant communities.

  12. A study of vibrational excitations of ozone in the framework of a polyad preserving model of interacting Morse oscillators

    Science.gov (United States)

    Bermúdez-Montaña, M.; Lemus, R.

    2017-01-01

    The vibrational spectroscopic description of the ozone molecule 16O3 in its electronic ground state X1A1 is presented in the framework of a simple local model, where Morse potentials are associated with both stretching and bending modes. The Hamiltonian is written in terms of internal coordinates considering the local mode character of the ozone molecule. Later on an algebraic representation in terms of Morse ladder operators is introduced through a linear approximation in the expansion of the coordinates and momenta. Three polyads are considered in our study: P11 =ν1 +ν3 +ν2 , P21 = 2 (ν1 +ν3) +ν2 , and P32 = 3 (ν1 +ν3) + 2ν2 , as suggested by resonances derived from the fundamentals as well as from previous variational analysis. The best description is provided by the P11 polyad scheme, yielding an rms deviation of 1.85 cm-1 for a fit involving 121 energy levels. Considering the other two polyads the description is less accurate: rms = 2.78 cm-1 for polyad P21 and rms = 2.63 cm-1 for polyad P32 , considering 99 and 100 energy levels, respectively. These fits represent the best descriptions in the framework of an algebraic approach. In addition, since our algebraic model keeps the connection with configuration space, the force constants derived from the three fits have been estimated. We have found that all the available experimental energies may be assigned at least to one of the three fits. As the energy increases the eigenstates obtained from different polyad schemes differ. This fact paves the way to establish a polyad breaking approach as a next step to improve the description.

  13. Taurine treatment preserves brain and liver mitochondrial function in a rat model of fulminant hepatic failure and hyperammonemia.

    Science.gov (United States)

    Jamshidzadeh, Akram; Heidari, Reza; Abasvali, Mozhgan; Zarei, Mehdi; Ommati, Mohammad Mehdi; Abdoli, Narges; Khodaei, Forouzan; Yeganeh, Yasaman; Jafari, Faezeh; Zarei, Azita; Latifpour, Zahra; Mardani, Elnaz; Azarpira, Negar; Asadi, Behnam; Najibi, Asma

    2017-02-01

    Ammonia-induced mitochondrial dysfunction and energy crisis is known as a critical consequence of hepatic encephalopathy (HE). Hence, mitochondria are potential targets of therapy in HE. The current investigation was designed to evaluate the role of taurine treatment on the brain and liver mitochondrial function in a rat model of hepatic encephalopathy and hyperammonemia. The animals received thioacetamide (400mg/kg, i.p, for three consecutive days at 24-h intervals) as a model of acute liver failure and hyperammonemia. Several biochemical parameters were investigated in the serum, while the animals' cognitive function and locomotor activity were monitored. Mitochondria was isolated from the rats' brain and liver and several indices were assessed in isolated mitochondria. Liver failure led to cognitive dysfunction and impairment in locomotor activity in the rats. Plasma and brain ammonia was high and serum markers of liver injury were drastically elevated in the thioacetamide-treated group. An assessment of brain and liver mitochondrial function in the thioacetamide-treated animals revealed an inhibition of succinate dehydrogenase activity (SDA), collapsed mitochondrial membrane potential, mitochondrial swelling, and increased reactive oxygen species (ROS). Furthermore, a significant decrease in mitochondrial ATP was detected in the brain and liver mitochondria isolated from thioacetamide-treated animals. Taurine treatment (250, 500, and 1000mg/kg) decreased mitochondrial swelling, ROS, and LPO. Moreover, the administration of this amino acid restored brain and liver mitochondrial ATP. These data suggest taurine to be a potential protective agent with therapeutic capability against hepatic encephalopathy and hyperammonemia-induced mitochondrial dysfunction and energy crisis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. The Importance of Preservation of Autochthonous Biotope of Pannonian Plane in the Area of Special Nature Reserve “Pašnjaci Velike Droplje“ for Education and Ecotourism Development

    Directory of Open Access Journals (Sweden)

    Milana Pasic

    2008-01-01

    Full Text Available In the past the region of Vojvodina was dominated by vast steppes, saline areas, marshes and flooded terrains. Wet terrains were converted into steppes during the Holocene climate changes, but the land under cultivation is gradually taking their place, too. Autochthonous biotope is preserved in some regions of Vojvodina. These regions are under state protection. Special nature reserve “Pašnjaci velike droplje“consists of saline areas and vast steppes and it is the only habitat of Great Bustard in Serbia. Reserve is located in north Banat. Development of ecotourism is based upon endangered ornithology species, heterogeneous fauna as well as upon up the educational purpose of the reserve. There are also possibilities for organizing of photo safaris and nature schools in the reserve. In order to protect autochthonous biotope, legal regulations on protection should be obeyed, fields should be revitalized i.e. they should be transformed into former state of natural mosaic of vast steppes and saline areas.

  15. Privacy-preserving distributed clustering

    DEFF Research Database (Denmark)

    Erkin, Zekeriya; Veugen, Thijs; Toft, Tomas

    2013-01-01

    by taking the distributed structure of the system into account and improving the efficiency in terms of computation and communication by data packing. While our construction can be easily adjusted to a centralized or a distributed computing model, we rely on a set of particular users that help the service...... provider with computations. Experimental results clearly indicate that the work we present is an efficient way of deploying a privacy-preserving clustering algorithm in a distributed manner....

  16. Preserving and documenting the Cultural Heritage

    Directory of Open Access Journals (Sweden)

    Deniz Özkut

    2012-10-01

    Full Text Available The phenomenon of preservation may be described as a physical process that depends onconceptual facts. When observed from a conceptual point of view, ‘values’ cause the divergencesin the preservation process, which could be named as the pre-requisites of the construction.Values carry emotional and physical points of view. The emotional context, of course, dependson recognizing and remembering while physical context depends on direction of research. They are indicators of cultural characteristics and historical identity. ‘Cultural values’1, more over, explains the meanings attributed to the cultural property, which meanings will be preserved, and the reasons for their preservation. On behalf of this context, the preservation process may be defined as the preservation of the cultural heritage within an effective system. This effective system isaimed at attaining the total quality as a result of a synthesis of the technology, technique, and material originally deployed with those of the present. Besides, one of the most important inputin the preservation process is the priorities of the intervention to be held, as the latter will determine the decisions and types of intervention during the implementation phase of the preservation project. As a significant paradox, the most important parameter that shapes both a preservationproject and its process appears to be the risks that consist of indefinite input preventing theproject from a proper definition of its context. Since all physical problems and the social statusof the cultural property to be preserved have direct impact upon the design process of thepreservation project, these priorities and the risks should be clarified in the course of pre-assessment phase at the beginning of the preservation process.

  17. Glycerol-Preserved Arterial Allografts Evaluated in the Infrarenal Rat Aorta

    National Research Council Canada - National Science Library

    Fahner, P.J; Idu, M.M; van Gulik, T.M; van Wijk, B; van der Wal, A.C; Legemate, D.A

    2009-01-01

    .... Since glycerol preservation proved effective for the storage of skin allografts, this preservation method was investigated for vascular allografts using a rat aortic transplantation model. Methods...

  18. VT Historic Preservation Grant

    Data.gov (United States)

    Vermont Center for Geographic Information — The State-funded Historic Preservation Grant Program helps municipalities and non-profit organizations rehabilitate the historic buildings that are a vital part of...

  19. A hydrogeomorphic river network model predicts where and why hyporheic exchange is important in large basins

    Science.gov (United States)

    Gomez-Velez, Jesus D.; Harvey, Judson W.

    2014-09-01

    Hyporheic exchange has been hypothesized to have basin-scale consequences; however, predictions throughout river networks are limited by available geomorphic and hydrogeologic data and by models that can analyze and aggregate hyporheic exchange flows across large spatial scales. We developed a parsimonious but physically based model of hyporheic flow for application in large river basins: Networks with EXchange and Subsurface Storage (NEXSS). We applied NEXSS across a broad range of geomorphic diversity in river reaches and synthetic river networks. NEXSS demonstrates that vertical exchange beneath submerged bed forms rather than lateral exchange through meanders dominates hyporheic fluxes and turnover rates along river corridors. Per kilometer, low-order streams have a biogeochemical potential at least 2 orders of magnitude larger than higher-order streams. However, when biogeochemical potential is examined per average length of each stream order, low- and high-order streams were often found to be comparable. As a result, the hyporheic zone's intrinsic potential for biogeochemical transformations is comparable across different stream orders, but the greater river miles and larger total streambed area of lower order streams result in the highest cumulative impact from low-order streams. Lateral exchange through meander banks may be important in some cases but generally only in large rivers.

  20. Digital preservation for heritages

    CERN Document Server

    Lu, Dongming

    2011-01-01

    ""Digital Preservation for Heritages: Technologies and Applications"" provides a comprehensive and up-to-date coverage of digital technologies in the area of cultural heritage preservation, including digitalization, research aiding, conservation aiding, digital exhibition, and digital utilization. Processes, technical frameworks, key technologies, as well as typical systems and applications are discussed in the book. It is intended for researchers and students in the fields of computer science and technology, museology, and archaeology. Dr. Dongming Lu is a professor at College of Computer Sci

  1. Preservation Copying Endangered Historic Negative Collections

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad

    2008-01-01

    This article discusses preservation copying of unstable B&W nitrate and acetate still photographic negatives. It focuses on evaluating two different strategies for preserving the copies from a point of view of quality and cost-effectiveness. The evaluated strategies are preservation of the master...... files in a digital repository and outputting the copies on film, which is preserved in a traditional storage facility. The issues are put into perspective by a case study completed at the Royal Library, where endangered nitrate negatives of unique national value have been digitized. The paper starts...... by describing essential characteristics of negatives, which must be passed on to the copies, and the required metadata and technical imaging specifications. Next the paper discusses strategies for preservation and makes an analysis with the LIFE2 Costing Model. The paper concludes that the most beneficial...

  2. Power Preservation Friendly Congestion Control

    Directory of Open Access Journals (Sweden)

    Ittipong Khemapech

    2014-03-01

    Full Text Available Wireless sensor networks (WSNs are an important area with a major technological impact. Power preservation is one of the important issues in communication protocol development for WSNs. This article presents a review of Event-to-Sink Reliable Transport (ESRT which is specifically developed for an event-based WSNs application. Five characteristic regions and corresponding algorithms have been proposed in ESRT. At the end of each cycle, the reliability is observed and the data reporting rate is adjusted accordingly. Two main contributions of this study include an evaluation of the algorithms proposed by ESRT on their capabilities of power preservation and convergence to the optimal state where a sink receives a desired number of received packets and there is no congestion. According to the results, all of the algorithms demonstrate profound reporting rate adjustments. Moreover, both transmitting and receiving powers can be significantly preserved in the case when the sources generated more packets than required and the network is congested. Therefore, the proposed algorithms unlikely require any enhancements. Moreover, ESRT is analysed how well it can fit in some of the existing WSNs applications. The application category which may deploy ESRT is the event detection and tracking where complete reliability is not required.

  3. Patient-specific induced pluripotent stem cells in neurological disease modeling: the importance of nonhuman primate models

    Directory of Open Access Journals (Sweden)

    Qiu Z

    2013-07-01

    Full Text Available Zhifang Qiu,1,2 Steven L Farnsworth,2 Anuja Mishra,1,2 Peter J Hornsby1,21Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, TX, USA; 2Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, TX, USAAbstract: The development of the technology for derivation of induced pluripotent stem (iPS cells from human patients and animal models has opened up new pathways to the better understanding of many human diseases, and has created new opportunities for therapeutic approaches. Here, we consider one important neurological disease, Parkinson's, the development of relevant neural cell lines for studying this disease, and the animal models that are available for testing the survival and function of the cells, following transplantation into the central nervous system. Rapid progress has been made recently in the application of protocols for neuroectoderm differentiation and neural patterning of pluripotent stem cells. These developments have resulted in the ability to produce large numbers of dopaminergic neurons with midbrain characteristics for further study. These cells have been shown to be functional in both rodent and nonhuman primate (NHP models of Parkinson's disease. Patient-specific iPS cells and derived dopaminergic neurons have been developed, in particular from patients with genetic causes of Parkinson's disease. For complete modeling of the disease, it is proposed that the introduction of genetic changes into NHP iPS cells, followed by studying the phenotype of the genetic change in cells transplanted into the NHP as host animal, will yield new insights into disease processes not possible with rodent models alone.Keywords: Parkinson's disease, pluripotent cell differentiation, neural cell lines, dopaminergic neurons, cell transplantation, animal models

  4. Importance of calibration for mathematical modeling of self-purification of lotic environments

    Directory of Open Access Journals (Sweden)

    Marcio Ricardo Salla

    Full Text Available Abstract: Aim To demonstrate the importance of calibration in mathematical modeling of self-purification in lotic environments, this study simulated the behavior of various parameters in a river with average annual flows between 4.0 and 32.0 m3.s-1, in a segment downstream from the entry of treated wastewater from a sewage treatment station (average monthly flow of 2.1 m3.s-1. Methods Numerical solution by finite difference of the advection-diffusion equation was used to study the dispersion and to quantify and monitor the evolution over time of the parameters DO, BOD5, Ptotal, NH3, NO3- and the levels of the heavy metals cadmium, chromium, copper, lead and zinc. The longitudinal behavior of the water quality parameters simulated by calibrating the state variables was compared with the behavior of the same parameters simulated via state variables available in the literature. The sensitivity of the state variables was also analyzed. Results The calibration process led to good fits between the simulated and actual data for all the parameters analyzed. On the other hand, the comparison of the water quality model using calibrated state variables with the model based on state variables obtained in the literature revealed inconsistencies regarding the parameters DO, Ptotal, ammonia, nitrate and all the heavy metals. Conclusions Considering the wide threshold ranges of the state variables in the literature and the dearth of studies on calibrating the coefficient of decay and quantifying the release of heavy metals by bottom sediment, this study can serve as a base for future investigations in lotic environments with similar hydraulic and water quality characteristics.

  5. OPR-PPR, a Computer Program for Assessing Data Importance to Model Predictions Using Linear Statistics

    Science.gov (United States)

    Tonkin, Matthew J.; Tiedeman, Claire R.; Ely, D. Matthew; Hill, Mary C.

    2007-01-01

    The OPR-PPR program calculates the Observation-Prediction (OPR) and Parameter-Prediction (PPR) statistics that can be used to evaluate the relative importance of various kinds of data to simulated predictions. The data considered fall into three categories: (1) existing observations, (2) potential observations, and (3) potential information about parameters. The first two are addressed by the OPR statistic; the third is addressed by the PPR statistic. The statistics are based on linear theory and measure the leverage of the data, which depends on the location, the type, and possibly the time of the data being considered. For example, in a ground-water system the type of data might be a head measurement at a particular location and time. As a measure of leverage, the statistics do not take into account the value of the measurement. As linear measures, the OPR and PPR statistics require minimal computational effort once sensitivities have been calculated. Sensitivities need to be calculated for only one set of parameter values; commonly these are the values estimated through model calibration. OPR-PPR can calculate the OPR and PPR statistics for any mathematical model that produces the necessary OPR-PPR input files. In this report, OPR-PPR capabilities are presented in the context of using the ground-water model MODFLOW-2000 and the universal inverse program UCODE_2005. The method used to calculate the OPR and PPR statistics is based on the linear equation for prediction standard deviation. Using sensitivities and other information, OPR-PPR calculates (a) the percent increase in the prediction standard deviation that results when one or more existing observations are omitted from the calibration data set; (b) the percent decrease in the prediction standard deviation that results when one or more potential observations are added to the calibration data set; or (c) the percent decrease in the prediction standard deviation that results when potential information on one

  6. Importance of Field Data for Numerical Modeling to Dam Removal on a Mountain Channel

    Science.gov (United States)

    Kuo, W. C.; Wang, H. W.

    2015-12-01

    In 2011, a 13-m high Chijiawan Dam on Chijiawan Creek was removed due to the safety concern due to aging structure and scoured dam foundation as well as habitat restoration of the endangered Formosan landlocked salmon. Similar to Chijiawan Dam, many dams in Taiwan are located in steep mountainous area with coarser sediment and high sediment yield, and may be removed in the near future. Since the capability of current sediment transport model is insufficient, a systematic planning of field survey and monitoring work can effectively help to decrease data uncertainty in simulation. In this study, we aimed to understand the minimum requirements of data for numerical model to predict channel responses after dam removal, according to the data of pre-project and long term post-project monitoring works from removal of Chijiawan dam. We collected the hourly discharge data of Taipower gaging station located 6.8 km from the dam from 2010 to 2012 and conducted surveys of grain size distributions, cross-sectional and longitudinal profiles. We applied Sedimentation and River Hydraulics (SRH) one-dimensional model to simulate bed elevation changes by different setting of data input, including bed sediment, roughness coefficient, cross-section spacing, and flow discharge. Then, we performed a sensitivity analysis by using Root Mean Square Error (RMSE) to evaluate the minimum requirements of data for predicting to dam removal. The RMSE variability of varied setting of bed sediment, roughness coefficient, cross-section spacing, and flow discharge ranged from 0.02 m, 0.17 m, 0.14 m and 0.09 m, respectively. The results highlight that the simulation is sensitive to roughness coefficient, cross-section spacing, and flow discharge, and less sensitive to bed sediment. We anticipate the results will help decision maker to understand the importance of field data in future removals.

  7. Importance of temporal resolution of meteorological forcings for physics-based snow modeling

    Science.gov (United States)

    Sohrabi, M.; Benjankar, R. M.; Kumar, M.; Marks, D. G.; Kormos, P.; Tonina, D.

    2015-12-01

    In alpine regions, snow delays hydrological responses to precipitation and controls initiation and length of the growing season. Therefore, precise simulations of snow accumulation and melt are crucial for understanding hydrological dynamics and predicting hydrologic response from watersheds. These predictions are important for water resource management and for ecological studies of vegetation distribution, growth and for wildlife habitat. Snow models require fine temporal resolution of meteorological inputs to capture diurnal changes. However, lack of meteorological data at fine-temporal resolution may force the use of coarser than hourly data. The objective of this work is to understand what sort of information can be lost over the watershed depending on the temporal resolution of meteorological inputs, for a range of hydroclimatic and topographic conditions. To address this goal, a spatially distributed and physics-based snow model (iSnobal) was run using 1-, 3- and 6-hourly meteorological inputs for a wet, average and a dry year over Boise River Basin (BRB), Idaho, USA. Simulated snow variables such as Snow Water Equivalent (SWE) and Surface Water Input (SWI - melt draining from the snowcover plus rain on bare ground) were averaged over 3 elevation bands including rain dominated (≤1400m), rain-snow transition (>1400 and ≤1900m) and snow dominated (>1900m). Except at the rain dominated band, using 6-hr inputs causes considerable overestimation of SWE and SWI, particularly in the wet year. The results show that at the rain-snow transition and snow dominated bands at least 3-hr meteorological data are necessary for snow modeling, due to strong diurnal changes in meteorological variables at these elevations. However, using course temporal resolution data for the rain dominated band made only a small difference in results.

  8. Importance-truncated no-core shell model for fermionic many-body systems

    Energy Technology Data Exchange (ETDEWEB)

    Spies, Helena

    2017-03-15

    The exact solution of quantum mechanical many-body problems is only possible for few particles. Therefore, numerical methods were developed in the fields of quantum physics and quantum chemistry for larger particle numbers. Configuration Interaction (CI) methods or the No-Core Shell Model (NCSM) allow ab initio calculations for light and intermediate-mass nuclei, without resorting to phenomenology. An extension of the NCSM is the Importance-Truncated No-Core Shell Model, which uses an a priori selection of the most important basis states. The importance truncation was first developed and applied in quantum chemistry in the 1970s and latter successfully applied to models of light and intermediate mass nuclei. Other numerical methods for calculations for ultra-cold fermionic many-body systems are the Fixed-Node Diffusion Monte Carlo method (FN-DMC) and the stochastic variational approach with Correlated Gaussian basis functions (CG). There are also such method as the Coupled-Cluster method, Green's Function Monte Carlo (GFMC) method, et cetera, used for calculation of many-body systems. In this thesis, we adopt the IT-NCSM for the calculation of ultra-cold Fermi gases at unitarity. Ultracold gases are dilute, strongly correlated systems, in which the average interparticle distance is much larger than the range of the interaction. Therefore, the detailed radial dependence of the potential is not resolved, and the potential can be replaced by an effective contact interaction. At low energy, s-wave scattering dominates and the interaction can be described by the s-wave scattering length. If the scattering length is small and negative, Cooper-pairs are formed in the Bardeen-Cooper-Schrieffer (BCS) regime. If the scattering length is small and positive, these Cooper-pairs become strongly bound molecules in a Bose-Einstein-Condensate (BEC). In between (for large scattering lengths) is the unitary limit with universal properties. Calculations of the energy spectra

  9. Multivariate Models of Parent-Late Adolescent Gender Dyads: The Importance of Parenting Processes in Predicting Adjustment

    Science.gov (United States)

    McKinney, Cliff; Renk, Kimberly

    2008-01-01

    Although parent-adolescent interactions have been examined, relevant variables have not been integrated into a multivariate model. As a result, this study examined a multivariate model of parent-late adolescent gender dyads in an attempt to capture important predictors in late adolescents' important and unique transition to adulthood. The sample…

  10. Historic Preservation Information CFM Website

    Data.gov (United States)

    Department of Veterans Affairs — The VA Historic Preservation Office keeps information about VA's programs to comply with Federal preservation requirements, and also interesting information about VA...

  11. Food Preservation beyond the Season.

    Science.gov (United States)

    Hanes, Phyllis

    1992-01-01

    Examines how current scientific knowledge of food preservation emerged from traditions handed down through the generations. Discusses various methods of preservation, their history, and current application. (LZ)

  12. Implementing digital preservation in repositories: Knowledge and practices

    Directory of Open Access Journals (Sweden)

    Caterina Groposo Pavão

    2016-09-01

    Full Text Available Digital preservation has to be undertaken by institutional repositories, which are responsible for the preservation of the scientific output from academic institutions. However, due to the constant evolution of the field, to gain domain knowledge and recognise best practices is a complex task for people responsible for digital preservation in those institutions. Digital preservation research, practices and solutions address specific problems, such as formats, curation, reference models, authenticity, policies and preservation plans, tools, etc., while stakeholders need an integrated, contextualized and applicable overview. This paper focuses on the implementation of digital preservation in repositories, from the perspective of the team responsible for the project, regarding the necessary knowledge and best practices. Initially, it defines and contextualizes digital preservation repositories. The following section presents a conceptual model of digital preservation, synthesized from conceptual models developed in influential projects in the field, which allows us to identify the domain knowledge in digital preservation. Finally, aspects represented in the model are discussed in the light of the performance of teams implementing digital preservation repositories. It provides recommendations, guides and examples that may be useful for the implementation of digital preservation. It points to the need to strengthen the relationship between domain knowledge in digital preservation repositories with practices developed in numerous projects developed worldwide.

  13. [The importance of model organisms to study cilia and flagella biology].

    Science.gov (United States)

    Vincensini, Laetitia; Blisnick, Thierry; Bastin, Philippe

    2011-01-01

    Cilia and flagella are ubiquitous organelles that protrude from the surfaces of many cells, and whose architecture is highly conserved from protists to humans. These complex organelles, composed of over 500 proteins, can be either immotile or motile. They are involved in a myriad of biological processes, including sensing (non-motile cilia) and/or cell motility or movement of extracellular fluids (motile cilia). The ever-expanding list of human diseases linked to defective cilia illustrates the functional importance of cilia and flagella. These ciliopathies are characterised by an impressive diversity of symptoms and an often complex genetic etiology. A precise knowledge of cilia and flagella biology is thus critical to better understand these pathologies. However, multi-ciliated cells are terminally differentiated and difficult to manipulate, and a primary cilium is assembled only when the cell exits from the cell cycle. In this context the use of model organisms, that relies on the high degree of structural but also of molecular conservation of these organelles across evolution, is instrumental to decipher the many facets of cilia and flagella biology. In this review, we highlight the specific strengths of the main model organisms to investigate the molecular composition, mode of assembly, sensing and motility mechanisms and functions of cilia and flagella. Pioneering studies carried out in the green alga Chlamydomonas established the link between cilia and several genetic diseases. Moreover, multicellular organisms such as mouse, zebrafish, Xenopus, C. elegans or Drosophila, and protists like Paramecium, Tetrahymena and Trypanosoma or Leishmania each bring specific advantages to the study of cilium biology. For example, the function of genes involved in primary ciliary dyskinesia (due to defects in ciliary motility) can be efficiently assessed in trypanosomes.

  14. Modeling loggerhead turtle movement in the Mediterranean: importance of body size and oceanography.

    Science.gov (United States)

    Eckert, Scott A; Moore, Jeffrey E; Dunn, Daniel C; van Buiten, Ricardo Sagarminaga; Eckert, Karen L; Halpin, Patrick N

    2008-03-01

    Adapting state-space models (SSMs) to telemetry data has been helpful for dealing with location error and for modeling animal movements. We used a combination of two hierarchical Bayesian SSMs to estimate movement pathways from Argos satellite-tag data for 15 juvenile loggerhead turtles (Caretta caretta) in the western Mediterranean Sea, and to probabilistically assign locations to one of two behavioral movement types and relate those behaviors to environmental features. A Monte Carlo procedure helped propagate location uncertainty from the first SSM into the estimation of behavioral states and environment--behavior relationships in the second SSM. Turtles using oceanic habitats of the Balearic Sea (n = 9 turtles) within the western Mediterranean were more likely to exhibit "intensive search" behavior as might occur during foraging, but only larger turtles responded to variations in sea-surface height. This suggests that they were better able than smaller turtles to cue on environmental features that concentrate prey resources or were more dependent on high-quality feeding areas. These findings stress the importance of individual heterogeneity in the analysis of movement behavior and, taken in concert with descriptive studies of Pacific loggerheads, suggest that directed movements toward patchy ephemeral resources may be a general property of larger juvenile loggerheads in different populations. We discovered size-based variation in loggerhead distribution and documented use of the western Mediterranean Sea by turtles larger than previously thought to occur there. With one exception, only individuals > 57 cm curved carapace length used the most westerly basin in the Mediterranean (western Alborán Sea). These observations shed new light on loggerhead migration phenology.

  15. 物联网空间内LBS隐私安全保护模型研究%Privacy-preserving model of LBS in Internet of Things

    Institute of Scientific and Technical Information of China (English)

    路红; 廖龙龙

    2014-01-01

    To solve the problem, the framework, various privacy threats and security needs of LBS in IoT are discussed, and a privacy-preserving model is designed which can protect privacy of real identity, physical location and service con-tent in IoT. The privacy security model is realized by using Onion Routing algorithm and fully homomorphic encryption algorithm. The analysis shows that this model can realize identity anonymity, position protection, service encryption, etc., and can keep safe of LBS privacy in IoT.%为解决物联网空间内LBS服务的隐私安全问题,在分析物联网环境中的LBS服务框架的基础上,针对其面临的各种隐私安全威胁及安全需求,基于匿名通信原理和可计算加密思想设计了一种支持真实身份、实体位置和服务内容等LBS隐私保护的安全模型,提出采用Onion Routing算法和全同态加密算法实现该模型。模型实现算法的分析表明,该模型可实现身份匿名、位置保护、服务加密等,对物联网空间内LBS隐私具有很好的安全保护。

  16. Abnormal calcium homeostasis in heart failure with preserved ejection fraction is related to both reduced contractile function and incomplete relaxation: an electromechanically detailed biophysical modeling study

    Science.gov (United States)

    Adeniran, Ismail; MacIver, David H.; Hancox, Jules C.; Zhang, Henggui

    2015-01-01

    Heart failure with preserved ejection fraction (HFpEF) accounts for about 50% of heart failure cases. It has features of incomplete relaxation and increased stiffness of the left ventricle. Studies from clinical electrophysiology and animal experiments have found that HFpEF is associated with impaired calcium homeostasis, ion channel remodeling and concentric left ventricle hypertrophy (LVH). However, it is still unclear how the abnormal calcium homeostasis, ion channel and structural remodeling affect the electro-mechanical dynamics of the ventricles. In this study we have developed multiscale models of the human left ventricle from single cells to the 3D organ, which take into consideration HFpEF-induced changes in calcium handling, ion channel remodeling and concentric LVH. Our simulation results suggest that at the cellular level, HFpEF reduces the systolic calcium level resulting in a reduced systolic contractile force, but elevates the diastolic calcium level resulting in an abnormal residual diastolic force. In our simulations, these abnormal electro-mechanical features of the ventricular cells became more pronounced with the increase of the heart rate. However, at the 3D organ level, the ejection fraction of the left ventricle was maintained due to the concentric LVH. The simulation results of this study mirror clinically observed features of HFpEF and provide new insights toward the understanding of the cellular bases of impaired cardiac electromechanical functions in heart failure. PMID:25852567

  17. Production inventory model for two-level trade credit financing under the effect of preservation technology and learning in supply chain

    Directory of Open Access Journals (Sweden)

    Sunil Kumar

    2015-12-01

    Full Text Available The present study investigated the inventory model for a retailer under two levels of trade credit to reflect the supply chain management. Supplier offers trade credit period of M to the retailer while in turn retailer provides a trade credit period of N to his/her customers. The supplier is willing to provide the retailer a full trade credit period for payments and the retailer offers the partial trade credit period to his/her customers. Here, selling items are considered as perishable items such as fruits, fresh fishes, gasoline, photographic films, etc. so that its potential worth decreases. It is assumed that decay in potential worth of items can be increased by using preservation technology. The demand is considered as the function of selling price and trade credit. Ordering cost can be reducing due to learning by doing phenomenon. By applying convex fractional programming results, we obtain necessary and sufficient conditions of an optimal solution. Some theorems are developed to determine retailer’s optimal ordering policies and numerical examples are given to illustrate these theorems. In addition, some managerial insights from the numerical examples are also concluded.

  18. Abnormal calcium homeostasis in heart failure with preserved ejection fraction is related to both reduced contractile function and incomplete relaxation: An electromechanically detailed biophysical modelling study

    Directory of Open Access Journals (Sweden)

    Ismail eAdeniran

    2015-03-01

    Full Text Available Heart failure with preserved ejection fraction (HFpEF accounts for about 50% of heart failure cases. It has features of incomplete relaxation and increased stiffness of the left ventricle. Studies from clinical electrophysiology and animal experiments have found that HFpEF is associated with impaired calcium homeostasis, ion channel remodelling and concentric left ventricle hypertrophy (LVH. However, it is still unclear how the abnormal calcium homeostasis, ion channel and structural remodelling affect the electro-mechanical dynamics of the ventricles. In this study we have developed multiscale models of the human left ventricle from single cells to the 3D organ, which take into consideration HFpEF-induced changes in calcium handling, ion channel remodelling and concentric LVH. Our simulation results suggest that at the cellular level, HFpEF reduces the systolic calcium level resulting in a reduced systolic contractile force, but elevates the diastolic calcium level resulting in an abnormal residual diastolic force. In our simulations, these abnormal electro-mechanical features of the ventricular cells became more pronounced with the increase of the heart rate. However, at the 3D organ level, the ejection fraction of the left ventricle was maintained due to the concentric LVH. The simulation results of this study mirror clinically observed features of HFpEF and provide new insights towards the understanding of the cellular bases of impaired cardiac electromechanical functions in heart failure.

  19. Hoxb8 conditionally immortalised macrophage lines model inflammatory monocytic cells with important similarity to dendritic cells.

    Science.gov (United States)

    Rosas, Marcela; Osorio, Fabiola; Robinson, Matthew J; Davies, Luke C; Dierkes, Nicola; Jones, Simon A; Reis e Sousa, Caetano; Taylor, Philip R

    2011-02-01

    We have examined the potential to generate bona fide macrophages (MØ) from conditionally immortalised murine bone marrow precursors. MØ can be derived from Hoxb8 conditionally immortalised macrophage precursor cell lines (MØP) using either M-CSF or GM-CSF. When differentiated in GM-CSF (GM-MØP) the resultant cells resemble GM-CSF bone marrow-derived dendritic cells (BMDC) in morphological phenotype, antigen phenotype and functional responses to microbial stimuli. In spite of this high similarity between the two cell types and the ability of GM-MØP to effectively present antigen to a T-cell hybridoma, these cells are comparatively poor at priming the expansion of IFN-γ responses from naïve CD4(+) T cells. The generation of MØP from transgenic or genetically aberrant mice provides an excellent opportunity to study the inflammatory role of GM-MØP, and reduces the need for mouse colonies in many studies. Hence differentiation of conditionally immortalised MØPs in GM-CSF represents a unique in vitro model of inflammatory monocyte-like cells, with important differences from bone marrow-derived dendritic cells, which will facilitate functional studies relating to the many 'sub-phenotypes' of inflammatory monocytes.

  20. Comparative Cytogenetics between Two Important Songbird, Models: The Zebra Finch and the Canary.

    Science.gov (United States)

    Dos Santos, Michelly da Silva; Kretschmer, Rafael; Frankl-Vilches, Carolina; Bakker, Antje; Gahr, Manfred; O Brien, Patricia C M; Ferguson-Smith, Malcolm A; de Oliveira, Edivaldo H C

    2017-01-01

    Songbird species (order Passeriformes, suborder Oscines) are important models in various experimental fields spanning behavioural genomics to neurobiology. Although the genomes of some songbird species were sequenced recently, the chromosomal organization of these species is mostly unknown. Here we focused on the two most studied songbird species in neuroscience, the zebra finch (Taeniopygia guttata) and the canary (Serinus canaria). In order to clarify these issues and also to integrate chromosome data with their assembled genomes, we used classical and molecular cytogenetics in both zebra finch and canary to define their chromosomal homology, localization of heterochromatic blocks and distribution of rDNA clusters. We confirmed the same diploid number (2n = 80) in both species, as previously reported. FISH experiments confirmed the occurrence of multiple paracentric and pericentric inversions previously found in other species of Passeriformes, providing a cytogenetic signature for this order, and corroborating data from in silico analyses. Additionally, compared to other Passeriformes, we detected differences in the zebra finch karyotype concerning the morphology of some chromosomes, in the distribution of 5S rDNA clusters, and an inversion in chromosome 1.

  1. Comparative Cytogenetics between Two Important Songbird, Models: The Zebra Finch and the Canary

    Science.gov (United States)

    dos Santos, Michelly da Silva; Kretschmer, Rafael; Frankl-Vilches, Carolina; Bakker, Antje; Gahr, Manfred; O´Brien, Patricia C. M.; Ferguson-Smith, Malcolm A.

    2017-01-01

    Songbird species (order Passeriformes, suborder Oscines) are important models in various experimental fields spanning behavioural genomics to neurobiology. Although the genomes of some songbird species were sequenced recently, the chromosomal organization of these species is mostly unknown. Here we focused on the two most studied songbird species in neuroscience, the zebra finch (Taeniopygia guttata) and the canary (Serinus canaria). In order to clarify these issues and also to integrate chromosome data with their assembled genomes, we used classical and molecular cytogenetics in both zebra finch and canary to define their chromosomal homology, localization of heterochromatic blocks and distribution of rDNA clusters. We confirmed the same diploid number (2n = 80) in both species, as previously reported. FISH experiments confirmed the occurrence of multiple paracentric and pericentric inversions previously found in other species of Passeriformes, providing a cytogenetic signature for this order, and corroborating data from in silico analyses. Additionally, compared to other Passeriformes, we detected differences in the zebra finch karyotype concerning the morphology of some chromosomes, in the distribution of 5S rDNA clusters, and an inversion in chromosome 1. PMID:28129381

  2. The Main Influencing Factors of Customer Trust in China’s Import Cross-Border E- commerce Business Model

    OpenAIRE

    Zhou, Lu; Liu, Jiaqi; Lu, Yanzhu

    2016-01-01

    China’s import cross-border e-commerce (CICBEC) business model differs from other online shopping business models in both the participators and transaction processes. Government as an important participator has greatly promoted the healthy and rapid development of this business model. As a vital topic in all kinds of businesses, customer trust is also a core research topic in online shopping. Many scholars have studied customer trust in traditional online shopping while few of them focused on...

  3. Training for Preservation Management

    Directory of Open Access Journals (Sweden)

    Mirjam M. Foot

    1999-05-01

    Full Text Available In August 1997 the first of a series of summer schools in Preservation Management was held at the Archivschule in Marburg (Germany. The school was organised by the ECPA, the LIBER Division on Preservation, ICA and the Archivschule itself and was aimed at archivists and librarians in management positions from European institutions. It dealt with managerial, organisational and financial aspects of preservation and required active participation by those attending. Apart from introductory sessions by the teaching staff at the Archivschule, a large part of the course took the form of working groups, discussions, assignments and role play, to which participants were expected to take their own experience and problems. The school was conducted in German. Topics, spread over five days, ranged from preservation in the context of the core activities of libraries and archives; planning of preservation projects; general management issues, such as resource management, budgeting, priority setting, communication and effecting change; to more detailed considerations of day-to-day issues, such as storage, disaster control, microfilming and digitising, mass conservation processes, and moulds and fungi.

  4. Cancer and fertility preservation

    DEFF Research Database (Denmark)

    Lambertini, Matteo; Del Mastro, Lucia; Pescio, Maria C

    2016-01-01

    cryopreservation and embryo/oocyte cryopreservation are standard strategies for fertility preservations in male and female patients, respectively; other strategies (e.g. pharmacological protection of the gonads and gonadal tissue cryopreservation) are considered experimental techniques. However, since then, new......In the last years, thanks to the improvement in the prognosis of cancer patients, a growing attention has been given to the fertility issues. International guidelines on fertility preservation in cancer patients recommend that physicians discuss, as early as possible, with all patients...... of reproductive age their risk of infertility from the disease and/or treatment and their interest in having children after cancer, and help with informed fertility preservation decisions. As recommended by the American Society of Clinical Oncology and the European Society for Medical Oncology, sperm...

  5. Mass preserving image registration for lung CT

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin Chien Pau

    2012-01-01

    This paper presents a mass preserving image registration algorithm for lung CT images. To account for the local change in lung tissue intensity during the breathing cycle, a tissue appearance model based on the principle of preservation of total lung mass is proposed. This model is incorporated...... into a standard image registration framework with a composition of a global affine and several free-form B-Spline transformations with increasing grid resolution. The proposed mass preserving registration method is compared to registration using the sum of squared intensity differences as a similarity function...... inhale phases of 4D-CT images. Registration errors, measured as the average distance between vessel tree centerlines in the matched images, are significantly lower for the proposed mass preserving image registration method in the second, third and fourth group, while there is no statistically significant...

  6. Preserved Collateral Blood Flow in the Endovascular M2CAO Model Allows for Clinically Relevant Profiling of Injury Progression in Acute Ischemic Stroke

    Science.gov (United States)

    Little, Philip; Kvist, Ola; Grankvist, Rikard; Jonsson, Stefan; Damberg, Peter; Söderman, Michael; Arnberg, Fabian; Holmin, Staffan

    2017-01-01

    Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans. Twenty-five Sprague-Dawley rats were subjected to Short (90 min), Intermediate (180 min) or Extended (600 min) transient M2CAO and examined longitudinally with interleaved diffusion-, T2- and arterial spin labeling perfusion-weighted magnetic resonance imaging before and after reperfusion. We identified a rapid emergence of cytotoxic edema within tissue regions undergoing infarction, progressing in several distinct phases in the form of subsequent moderation and then reversal at 230 min (p < 0.0001). We identified also the early emergence of vasogenic edema, which increased consistently before and after reperfusion (p < 0.0001). The perfusion of the penumbra correlated more strongly to the perfusion of adjacent tissue regions than did the perfusion of regions undergoing infarction (p = 0.0088). This was interpreted as an effect of preserved collateral blood flow during M2CAO. Accordingly, we observed only limited recruitment of penumbra regions to the infarction core. However, a gradual increase in infarction size was still occurring as late as 10 hours after M2CAO. Our results indicate that patients suffering MCA branch occlusion stand to benefit from interventional therapy for an extended time period after the emergence of ischemic injury. PMID:28068417

  7. Advanced Digital Preservation

    CERN Document Server

    Giaretta, David

    2011-01-01

    There is growing recognition of the need to address the fragility of digital information, on which our society heavily depends for smooth operation in all aspects of daily life. This has been discussed in many books and articles on digital preservation, so why is there a need for yet one more? Because, for the most part, those other publications focus on documents, images and webpages -- objects that are normally rendered to be simply displayed by software to a human viewer. Yet there are clearly many more types of digital objects that may need to be preserved, such as databases, scientific da

  8. Salt effects on functional traits in model and in economically important Lotus species.

    Science.gov (United States)

    Uchiya, P; Escaray, F J; Bilenca, D; Pieckenstain, F; Ruiz, O A; Menéndez, A B

    2016-07-01

    A common stress on plants is NaCl-derived soil salinity. Genus Lotus comprises model and economically important species, which have been studied regarding physiological responses to salinity. Leaf area ratio (LAR), root length ratio (RLR) and their components, specific leaf area (SLA) and leaf mass fraction (LMF) and specific root length (SRL) and root mass fraction (RMF) might be affected by high soil salinity. We characterised L. tenuis, L. corniculatus, L. filicaulis, L. creticus, L. burtii and L. japonicus grown under different salt concentrations (0, 50, 100 and 150 mm NaCl) on the basis of SLA, LMF, SRL and RMF using PCA. We also assessed effects of different salt concentrations on LAR and RLR in each species, and explored whether changes in these traits provide fitness benefit. Salinity (150 mm NaCl) increased LAR in L. burtii and L. corniculatus, but not in the remaining species. The highest salt concentration caused a decrease of RLR in L. japonicus Gifu, but not in the remaining species. Changes in LAR and RLR would not be adaptive, according to adaptiveness analysis, with the exception of SLA changes in L. corniculatus. PCA revealed that under favourable conditions plants optimise surfaces for light and nutrient acquisition (SLA and SRL), whereas at higher salt concentrations they favour carbon allocation to leaves and roots (LMF and RMF) in detriment to their surfaces. PCA also showed that L. creticus subjected to saline treatment was distinguished from the remaining Lotus species. We suggest that augmented carbon partitioning to leaves and roots could constitute a salt-alleviating mechanism through toxic ion dilution.

  9. Moving Image Preservation in Libraries.

    Science.gov (United States)

    De Stefano, Paula

    2003-01-01

    Examines the current practices of film and video preservation in libraries and examines barriers that have hindered the development of full-fledged preservation programs for them. Topics include advances in education and training; preservation paradigms; and mechanics of film production that affect preservation. (Author/LRW)

  10. Planets: Integrated Services for Digital Preservation

    Directory of Open Access Journals (Sweden)

    Adam Farquhar

    2007-12-01

    Full Text Available The Planets Project is developing services and technology to address core challenges in digital preservation. This article introduces the motivation for this work, describes the extensible technical architecture and places the Planets approach into the context of the Open Archival Information System (OAIS Reference Model. It also provides a scenario demonstrating Planets’ usefulness in solving real-life digital preservation problems and an overview of the project’s progress to date.

  11. Modeling Leptospirosis in Trinidad, West Indies: A Waterborne Zoonosis of Increasing Public Health Importance

    Science.gov (United States)

    Vega, M. C.; Opadeyi, J.

    2012-12-01

    draining soils, percentage of imperfectly draining soils, percentage of impeded draining soils and mean annual rainfall. These covariables together with socio-economic data were used to set up the GWR models. Local model correlation (R^{2}) was 0.78, higher than the global correlation of 0.58 and there was found to be a clear spatial correlation between covariables and leptospirosis cases. Percentage of draining soils and topography were found to be significant (p<0.01 and 0.00) indicating spatial variability in the influence of these factors on the occurrence of leptospirosis in Trinidad communities. Composition of the soils and their lack of drainage may be an important factor influencing leptospirosis occurrence. Leptospires do not have a waterproof membrane therefore for their survival they must remain submersed in water. Previous studies have found leptospires to be associated with soils of high moisture and organic matter content.

  12. Inhibition of C5a-induced inflammation with preserved C5b-9-mediated bactericidal activity in a human whole blood model of meningococcal sepsis.

    NARCIS (Netherlands)

    Sprong, T.; Brandtzaeg, P.; Fung, M.; Pharo, A.M.; Hoiby, E.A.; Michaelsen, T.E.; Aase, A.; Meer, J.W.M. van der; Deuren, M. van; Mollnes, T.E.

    2003-01-01

    The complement system plays an important role in the initial defense against Neisseria meningitidis. In contrast, uncontrolled activation in meningococcal sepsis contributes to the development of tissue damage and shock. In a novel human whole blood model of meningococcal sepsis, we studied the effe

  13. Inhibition of C5a-induced inflammation with preserved C5b-9-mediated bactericidal activity in a human whole blood model of meningococcal sepsis.

    NARCIS (Netherlands)

    Sprong, T.; Brandtzaeg, P.; Fung, M.; Pharo, A.M.; Hoiby, E.A.; Michaelsen, T.E.; Aase, A.; Meer, J.W.M. van der; Deuren, M. van; Mollnes, T.E.

    2003-01-01

    The complement system plays an important role in the initial defense against Neisseria meningitidis. In contrast, uncontrolled activation in meningococcal sepsis contributes to the development of tissue damage and shock. In a novel human whole blood model of meningococcal sepsis, we studied the

  14. Importance of global aerosol modeling including secondary organic aerosol formed from monoterpene

    OpenAIRE

    Goto, Daisuke; Takemura, Toshihiko; Nakajima, Teruyuki

    2008-01-01

    A global three-dimensional aerosol transport-radiation model, coupled to an atmospheric general circulation model (AGCM), has been extended to improve the model process for organic aerosols, particularly secondary organic aerosols (SOA), and to estimate SOA contributions to direct and indirect radiative effects. Because the SOA formation process is complicated and unknown, the results in different model simulations include large differences. In this work, we simulate SOA production assuming v...

  15. An Importance Sampling Scheme for Models in a Strong External Field

    CERN Document Server

    Molkaraie, Mehdi

    2015-01-01

    We propose Monte Carlo methods to estimate the partition function of the two-dimensional Ising model in the presence of an external magnetic field. The estimation is done in the dual of the Forney factor graph representing the model. The proposed methods can efficiently compute an estimate of the partition function in a wide range of model parameters. As an example, we consider models that are in a strong external field.

  16. Improved Edge Awareness in Discontinuity Preserving Smoothing

    CERN Document Server

    Heinrich, Stuart B

    2011-01-01

    Discontinuity preserving smoothing is a fundamentally important procedure that is useful in a wide variety of image processing contexts. It is directly useful for noise reduction, and frequently used as an intermediate step in higher level algorithms. For example, it can be particularly useful in edge detection and segmentation. Three well known algorithms for discontinuity preserving smoothing are nonlinear anisotropic diffusion, bilateral filtering, and mean shift filtering. Although slight differences make them each better suited to different tasks, all are designed to preserve discontinuities while smoothing. However, none of them satisfy this goal perfectly: they each have exception cases in which smoothing may occur across hard edges. The principal contribution of this paper is the identification of a property we call edge awareness that should be satisfied by any discontinuity preserving smoothing algorithm. This constraint can be incorporated into existing algorithms to improve quality, and usually ha...

  17. Preserving Southwest Virginia's Folklore.

    Science.gov (United States)

    Burgin, Ramond

    1997-01-01

    Describes Southwest Virginia's rich tradition of folklore and culture and the need for its preservation. Summarizes the author's time-consuming process of preparing an inventory and indexing the vast archival collections gathered by students in American Folklore classes at Mountain Empire Community College and by the Southwest Virginia Folklore…

  18. POLARISATION PRESERVING OPTICAL FIBRE

    DEFF Research Database (Denmark)

    2000-01-01

    . This cladding structure provides polarisation preserving properties to the optical fibre. Optical fibres using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice - such as cladding providing Photonic Band Gap (PBG) effects....

  19. Paints and Preservatives.

    Science.gov (United States)

    Powell, Larry E.; Miller, Larry E.

    The publication contains an outline for use by agriculture teachers in developing a teaching plan for a unit on paints and preservatives. The topics included are (1) recognizing, solving, and preventing paint problems and (2) operating and using power spray painting equipment. Items presented for each topic are: the situation, (intended to inform…

  20. Kinetic modeling of mechanisms of industrially important organic reactions in gas and liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Vahteristo, K.

    2010-07-01

    This dissertation is based on 5 articles which deal with reaction mechanisms of the following selected industrially important organic reactions: 1. dehydrocyclization of n-butylbenzene to produce naphthalene, 2. dehydrocyclization of 1-(p-tolyl)-2-methylbutane (MB) to produce 2,6-dimethylnaphthalene, 3. esterification of neopentyl glycol (NPG) with different carboxylic acids to produce monoesters, 4. skeletal isomerization of 1-pentene to produce 2-methyl-1-butene and 2-methyl-2-butene. The results of initial- and integral-rate experiments of n-butylbenzene dehydrocyclization over selfmade chromia/alumina catalyst were applied when investigating reaction 2. Reaction 2 was performed using commercial chromia/alumina of different acidity, platina on silica and vanadium/calcium/alumina as catalysts. On all catalysts used for the dehydrocyclization, major reactions were fragmentation of MB and 1-(p-tolyl)-2-methylbutenes (MBes), dehydrogenation of MB, double bond transfer, hydrogenation and 1,6-cyclization of MBes. Minor reactions were 1,5-cyclization of MBes and methyl group fragmentation of 1,6- cyclization products. Esterification reactions of NPG were performed using three different carboxylic acids: propionic, isobutyric and 2-ethylhexanoic acid. Commercial heterogeneous gellular (Dowex 50WX2), macroreticular (Amberlyst 15) type resins and homogeneous para-toluene sulfonic acid were used as catalysts. At first NPG reacted with carboxylic acids to form corresponding monoester and water. Then monoester esterified with carboxylic acid to form corresponding diester. In disproportionation reaction two monoester molecules formed NPG and corresponding diester. All these three reactions can attain equilibrium. Concerning esterification, water was removed from the reactor in order to prevent backward reaction. Skeletal isomerization experiments of 1-pentene were performed over HZSM-22 catalyst. Isomerization reactions of three different kind were detected: double bond, cis

  1. Reduced motor neuron excitability is an important contributor to weakness in a rat model of sepsis.

    Science.gov (United States)

    Nardelli, Paul; Vincent, Jacob A; Powers, Randall; Cope, Tim C; Rich, Mark M

    2016-08-01

    The mechanisms by which sepsis triggers intensive care unit acquired weakness (ICUAW) remain unclear. We previously identified difficulty with motor unit recruitment in patients as a novel contributor to ICUAW. To study the mechanism underlying poor recruitment of motor units we used the rat cecal ligation and puncture model of sepsis. We identified striking dysfunction of alpha motor neurons during repetitive firing. Firing was more erratic, and often intermittent. Our data raised the possibility that reduced excitability of motor neurons was a significant contributor to weakness induced by sepsis. In this study we quantified the contribution of reduced motor neuron excitability and compared its magnitude to the contributions of myopathy, neuropathy and failure of neuromuscular transmission. We injected constant depolarizing current pulses (5s) into the soma of alpha motor neurons in the lumbosacral spinal cord of anesthetized rats to trigger repetitive firing. In response to constant depolarization, motor neurons in untreated control rats fired at steady and continuous firing rates and generated smooth and sustained tetanic motor unit force as expected. In contrast, following induction of sepsis, motor neurons were often unable to sustain firing throughout the 5s current injection such that force production was reduced. Even when firing, motor neurons from septic rats fired erratically and discontinuously, leading to irregular production of motor unit force. Both fast and slow type motor neurons had similar disruption of excitability. We followed rats after recovery from sepsis to determine the time course of resolution of the defect in motor neuron excitability. By one week, rats appeared to have recovered from sepsis as they had no piloerection and appeared to be in no distress. The defects in motor neuron repetitive firing were still striking at 2weeks and, although improved, were present at one month. We infer that rats suffered from weakness due to reduced

  2. Salted and preserved duck eggs: a consumer market segmentation analysis.

    Science.gov (United States)

    Arthur, Jennifer; Wiseman, Kelleen; Cheng, K M

    2015-08-01

    The combination of increasing ethnic diversity in North America and growing consumer support for local food products may present opportunities for local producers and processors in the ethnic foods product category. Our study examined the ethnic Chinese (pop. 402,000) market for salted and preserved duck eggs in Vancouver, British Columbia (BC), Canada. The objective of the study was to develop a segmentation model using survey data to categorize consumer groups based on their attitudes and the importance they placed on product attributes. We further used post-segmentation acculturation score, demographics and buyer behaviors to define these groups. Data were gathered via a survey of randomly selected Vancouver households with Chinese surnames (n = 410), targeting the adult responsible for grocery shopping. Results from principal component analysis and a 2-step cluster analysis suggest the existence of 4 market segments, described as Enthusiasts, Potentialists, Pragmatists, Health Skeptics (salted duck eggs), and Neutralists (preserved duck eggs). Kruskal Wallis tests and post hoc Mann-Whitney tests found significant differences between segments in terms of attitudes and the importance placed on product characteristics. Health Skeptics, preserved egg Potentialists, and Pragmatists of both egg products were significantly biased against Chinese imports compared to others. Except for Enthusiasts, segments disagreed that eggs are 'Healthy Products'. Preserved egg Enthusiasts had a significantly lower acculturation score (AS) compared to all others, while salted egg Enthusiasts had a lower AS compared to Health Skeptics. All segments rated "produced in BC, not mainland China" products in the "neutral to very likely" range for increasing their satisfaction with the eggs. Results also indicate that buyers of each egg type are willing to pay an average premium of at least 10% more for BC produced products versus imports, with all other characteristics equal. Overall

  3. Origin of Individual Differences in Importance Attached to Work: A Model and a Contribution to Its Evaluation.

    Science.gov (United States)

    Sverko, Branimir

    1989-01-01

    Tested model proposing that importance of work for individual depends on individual's perception of possibilities for attainment of personal salient work values through working. Responses from 1,872 high school students, 348 university students, and 344 adults to measures on importance of 20 work values, perceptions of their attainment…

  4. Modeling and monitoring - important elements in a pipeline integrity management system

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Roy; Gartland, Per O. [Force Technology (Norway); Baxandall, Daryl [Force Technology (Canada); Souza Junior, Helio A. de [Corrocean do Brasil Ltda., RJ (Brazil)

    2003-07-01

    A unique model for prediction of corrosion profiles in oil and gas pipelines has been created. The model is based on multiphase flow modeling, water wetting predictions, pH calculations and models of CO{sub 2} and H{sub 2}S corrosion. The input data are typically the pipeline profile, fluid composition data, production rates and data on injected chemicals. It is possible to combine the model with inspection or monitoring data. Based on the uncertainty related to the model and the available data, a probability distribution for the corrosion predictions is established. The result is combined with existing codes for the allowable corrosion attack in pressurized pipes and used to assess the need for pipeline inspection based on the risk of pipeline failure. Detailed example is given for a crude oil pipeline. (author)

  5. The importance of erosion for debris flow runout modelling from applications to the Swiss Alps

    OpenAIRE

    F. Frank; B. W. McArdell; Huggel, C; A. Vieli

    2015-01-01

    This study describes an investigation of channel-bed erosion of sediment by debris flows. An erosion model, developed using field data from debris flows at the Illgraben catchment, Switzerland, was incorporated into the existing RAMMS debris-flow model, which solves the 2-D shallow-water equations for granular flows. In the erosion model, the relationship between maximum shear stress and measured erosion is used to determine the maximum potential erosion depth. Additionally,...

  6. The importance of temporal collocation for the evaluation of aerosol models with observations

    Science.gov (United States)

    Schutgens, N. A. J.; Partridge, D. G.; Stier, P.

    2016-01-01

    It is often implicitly assumed that over suitably long periods the mean of observations and models should be comparable, even if they have different temporal sampling. We assess the errors incurred due to ignoring temporal sampling and show that they are of similar magnitude as (but smaller than) actual model errors (20-60 %).Using temporal sampling from remote-sensing data sets, the satellite imager MODIS (MODerate resolution Imaging Spectroradiometer) and the ground-based sun photometer network AERONET (AErosol Robotic NETwork), and three different global aerosol models, we compare annual and monthly averages of full model data to sampled model data. Our results show that sampling errors as large as 100 % in AOT (aerosol optical thickness), 0.4 in AE (Ångström Exponent) and 0.05 in SSA (single scattering albedo) are possible. Even in daily averages, sampling errors can be significant. Moreover these sampling errors are often correlated over long distances giving rise to artificial contrasts between pristine and polluted events and regions. Additionally, we provide evidence that suggests that models will underestimate these errors. To prevent sampling errors, model data should be temporally collocated to the observations before any analysis is made.We also discuss how this work has consequences for in situ measurements (e.g. aircraft campaigns or surface measurements) in model evaluation.Although this study is framed in the context of model evaluation, it has a clear and direct relevance to climatologies derived from observational data sets.

  7. Extension of CAVS coarse-grained model to phospholipid membranes: The importance of electrostatics.

    Science.gov (United States)

    Shen, Hujun; Deng, Mingsen; Zhang, Yachao

    2017-05-15

    It is evident from experiment that electrostatic potential (or dipole potential) is positive inside PC or PE lipid bilayers in the absence of ions. MARTINI coarse-grained (CG) model, which has been widely used in simulating physical properties of lipid bilayers, fails to reproduce the positive value for the dipole potential in the membrane interior. Although the total dipole potential can be correctly described by the BMW/MARTINI model, the contribution from the ester dipoles, playing a nontrivial role in the electrostatic potential across lipid membranes, is neglected by this hybrid approach. In the ELBA CG model, the role of the ester dipoles is considered, but it is overweighed because various atomistic models have consistently shown that water is actually the leading contributor of dipole potential. Here, we present a CG approach by combining the BMW-like water model (namely CAVS model) with the ELBA-like lipid model proposed in this work. Our CG model was designed not only to correctly reproduce the positive values for the dipole potential inside PC and PE lipid bilayers but also to properly balance the individual contributions from the ester dipoles and water, surmounting the limitations of current CG models in the calculations of dipole potential. © 2017 Wiley Periodicals, Inc.

  8. Impact of GlobalGAP certification on EU banana imports: A gravity modeling approach

    OpenAIRE

    Masood, Amjad; Brümmer, Bernhard

    2014-01-01

    Adopting a gravity framework and using data from 2010 to 2012 for 74 countries, we investigate whether the intensity of GlobalGAP standard adoption has a positive impact on EU banana import values. Intensity is measured by using number of GlobalGAP certified producers and hectares harvested under GlobalGAP certification. Using random and fixed effect estimation we find that intensity of certification, in terms of producers and hectares are associated with higher banana imports. However the es...

  9. Landscape-based population viability models demonstrate importance of strategic conservation planning for birds

    Science.gov (United States)

    Thomas W. Bonnot; Frank R. Thompson; Joshua J. Millspaugh; D. Todd. Jones-Farland

    2013-01-01

    Efforts to conserve regional biodiversity in the face of global climate change, habitat loss and fragmentation will depend on approaches that consider population processes at multiple scales. By combining habitat and demographic modeling, landscape-based population viability models effectively relate small-scale habitat and landscape patterns to regional population...

  10. The importance of temporal collocation for the evaluation of aerosol models with observations

    Directory of Open Access Journals (Sweden)

    N. A. J. Schutgens

    2015-09-01

    Full Text Available It is often implicitly assumed that over suitably long periods the mean of observations and models should be comparable, even if they have different temporal sampling. We assess the errors incurred due to ignoring temporal sampling and show they are of similar magnitude as (but smaller than actual model errors (20–60 %. Using temporal sampling from remote sensing datasets (the satellite imager MODIS and the ground-based sun photometer network AERONET and three different global aerosol models, we compare annual and monthly averages of full model data to sampled model data. Our results show that sampling errors as large as 100 % in AOT (Aerosol Optical Thickness, 0.4 in AE (Ångström Exponent and 0.05 in SSA (Single Scattering Albedo are possible. Even in daily averages, sampling errors can be significant. More-over these sampling errors are often correlated over long distances giving rise to artificial contrasts between pristine and polluted events and regions. Additionally, we provide evidence that suggests that models will underestimate these errors. To prevent sampling errors, model data should be temporally collocated to the observations before any analysis is made. We also discuss how this work has consequences for in-situ measurements (e.g. aircraft campaigns or surface measurements in model evaluation.

  11. The importance of accurate muscle modelling for biomechanical analyses: a case study with a lizard skull

    Science.gov (United States)

    Gröning, Flora; Jones, Marc E. H.; Curtis, Neil; Herrel, Anthony; O'Higgins, Paul; Evans, Susan E.; Fagan, Michael J.

    2013-01-01

    Computer-based simulation techniques such as multi-body dynamics analysis are becoming increasingly popular in the field of skull mechanics. Multi-body models can be used for studying the relationships between skull architecture, muscle morphology and feeding performance. However, to be confident in the modelling results, models need to be validated against experimental data, and the effects of uncertainties or inaccuracies in the chosen model attributes need to be assessed with sensitivity analyses. Here, we compare the bite forces predicted by a multi-body model of a lizard (Tupinambis merianae) with in vivo measurements, using anatomical data collected from the same specimen. This subject-specific model predicts bite forces that are very close to the in vivo measurements and also shows a consistent increase in bite force as the bite position is moved posteriorly on the jaw. However, the model is very sensitive to changes in muscle attributes such as fibre length, intrinsic muscle strength and force orientation, with bite force predictions varying considerably when these three variables are altered. We conclude that accurate muscle measurements are crucial to building realistic multi-body models and that subject-specific data should be used whenever possible. PMID:23614944

  12. SEAGRASS STRESS RESPONSE MODEL: THE IMPORTANCE OF LIGHT, TEMPERATURE, SEDIMENTATION AND GEOCHEMISTRY

    Science.gov (United States)

    Our objective is to define interactions between seagrass and water-column and sediment stressors. The model was developed and optimized for sediments in Thalassia testudinum seagrass beds of Lower Laguna Madre, Texas, USA and is composed of a plant sub-model and a sediment diagen...

  13. Importance of fish behaviour in modelling conservation problems: food limitation as an example

    Science.gov (United States)

    Steven Railsback; Bret Harvey

    2011-01-01

    Simulation experiments using the inSTREAM individual-based brown trout Salmo trutta population model explored the role of individual adaptive behaviour in food limitation, as an example of how behaviour can affect managers’ understanding of conservation problems. The model includes many natural complexities in habitat (spatial and temporal variation in characteristics...

  14. Mathematical modeling of the intracellular protein dynamics: the importance of active transport along microtubules.

    Science.gov (United States)

    Szymańska, Zuzanna; Parisot, Martin; Lachowicz, Mirosław

    2014-12-21

    In this paper we propose a mathematical model of protein and mRNA transport inside a cell. The spatio-temporal model takes into account the active transport along microtubules in the cytoplasm as well as diffusion and is able to reproduce the oscillatory changes in protein concentration observed in many experimental data. In the model the protein and the mRNA interact with each other that allows us to classify the model as a simple gene regulatory network. The proposed model is generic and may be adapted to specific signaling pathways. On the basis of numerical simulations, we formulate a new hypothesis that the oscillatory dynamics is allowed by the mRNA active transport along microtubules from the nucleus to distant locations.

  15. The importance of spatial models for estimating the strength of density dependence

    DEFF Research Database (Denmark)

    Thorson, James T.; Skaug, Hans J.; Kristensen, Kasper;

    2014-01-01

    Identifying the existence and magnitude of density dependence is one of the oldest concerns in ecology. Ecologists have aimed to estimate density dependence in population and community data by fitting a simple autoregressive (Gompertz) model for density dependence to time series of abundance...... for an entire population. However, it is increasingly recognized that spatial heterogeneity in population densities has implications for population and community dynamics. We therefore adapt the Gompertz model to approximate local densities over continuous space instead of population-wide abundance......, and to allow productivity to vary spatially. Using simulated data generated from a spatial model, we show that the conventional (nonspatial) Gompertz model will result in biased estimates of density dependence, e.g., identifying oscillatory dynamics when not present. By contrast, the spatial Gompertz model...

  16. LIBER's Involvement in Supporting Digital Preservation in Member Libraries

    Directory of Open Access Journals (Sweden)

    Paul Ayris

    2009-03-01

    Full Text Available Digital curation and preservation represent new challenges for universities. LIBER has invested considerable effort to engage with the new agendas of digital preservation and digital curation. Through two successful phases of the LIFE project, LIBER is breaking new ground in identifying innovative models for costing digital curation and preservation. Through LIFE’s input into the US-UK Blue Ribbon Task Force on Sustainable Digital Preservation and Access, LIBER is aligned with major international work in the economics of digital preservation. In its emerging new strategy and structures, LIBER will continue to make substantial contributions in this area, mindful of the needs of European research libraries.

  17. Relative importance of fuel management, ignition management and weather for area burned: Evidence from five landscape-fire-succession models

    Science.gov (United States)

    Geoffrey J. Cary; Mike D. Flannigan; Robert E. Keane; Ross A. Bradstock; Ian D. Davies; James M. Lenihan; Chao Li; Kimberley A. Logan; Russell A. Parsons

    2009-01-01

    The behaviour of five landscape fire models (CAFE, FIRESCAPE, LAMOS(HS), LANDSUM and SEMLAND) was compared in a standardised modelling experiment. The importance of fuel management approach, fuel management effort, ignition management effort and weather in determining variation in area burned and number of edge pixels burned (a measure of potential impact on assets...

  18. Tidal marsh accretion processes in the San Francisco Bay-Delta - are our models underestimating the historic and future importance of plant-mediated organic accretion?

    Science.gov (United States)

    Windham-Myers, L.; Drexler, J. Z.; Byrd, K. B.; Schile, L. M.

    2012-12-01

    Peat-accreting coastal wetlands have the potential to keep elevational pace with sea-level rise, thus providing both adaptation and mitigation for expected rises in atmospheric concentrations of greenhouse gases (GHGs). Due to oxidation and sedimentation processes, marsh elevations are generally constrained by sea level rise (1-2 mm yr-1). However, the relative importance of mineral vs. organic accretion remain poorly understood. At least four lines of evidence from the brackish-fresh region of California's SFBay-Delta suggest that potential rates of organic accretion may be underestimated in calibration datasets of the last century. First, tidal marsh elevations have been maintained with changing rates of SLR over the past 6700 years even during periods of low sediment availability. Second, the presence of fibric remnants in historic peat cores suggests that millennial preservation of autochtonous material may be greater in the absence of mineral inputs. Third, an experimental restoration of emergent marsh on subsided peat soil has generated new "proto-peat" at average rates of 4 cm y-1, nearly 40-times mean sea level rise, storing an average of 1 kg C m-2 yr-1 since 1997. Fourth, annual measurements of root production of the dominant fresh-brackish marsh species tule (Schoenoplectus acutus) show high productivity and minimal sensitivity to variable tidal range elevations and fresh-brackish salinities. Separating the relative importance of belowground productivity from decomposition in driving rates of organic accretion may be possible by assessment of fibric remnants, as an index of organic "preservation". Using three distinct peat cores from a larger study with calibrated dating and geochemistry data, fibric remnants (particles >2mm) were assessed at 10 cm intervals and compared with physical and associated geochemical down-core variability (n=230 segments). The presence of fibric remnants was reduced in the presence of sediment, as indicated by mineral content

  19. Allometry in global models: an important reality check on the growth and biomass of forests

    Science.gov (United States)

    Wolf, A.; Berry, J. A.

    2009-12-01

    Data assimilation incorporates information into a model of nature, and regardless of the algorithm employed the success of DA rests heavily on the quality of both the data and the model. Here we ask the question: if would could assimilate biomass from remote sensing or direct observation, could the models accommodate this information? We find that the state variables that are simulated by land surface models, such as biomass per unit area, are not amenable to developing an "observation operator" necessary for comparison with data. That is, lidar, radar, and multi-angle observations are sensitive to the size and shape of individual trees, whereas most land surface models have no representation of an individual. In addition, most land surface models make no distinction between aboveground and belowground woody biomass. We used the Cannell (1982) forest inventory database to individuate the biomass simulated in land surface models and found that the scaling of biomass pools - leaves, stem, coarse and fine roots - do not obey widely observed empirical and theoretical allometric constraints that are observed for individual trees (Enquist and Niklas, 2002), suggesting that the fractional allocation to these pools and their characteristic turnover times are in error. This discrepancy represents a gap in the translation of research on individual-based allocation to the stand level, where self-pruning and competition are manifest in the observed fluxes and biomass pools per unit area. We develop an approach to synthesize individual-based allocation with area-based flux models using a recent database of component flux and biomass compiled from Fluxnet sites (Luyssaert et al., 2008). We present the size-dependent pattern of allocation and turnover time for forest biomass pools at the spatial scale appropriate for land surface models. We discuss the implications of these results at the global scale for forests with changing size and age structure.

  20. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadingson Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    This paper discusses the influence of wave load sampling frequency on calculated sliding distance in an overall stability analysis of a monolithic caisson. It is demonstrated by a specific example of caisson design that for this kind of analyses the sampling frequency in a small scale model could...... be as low as 100 Hz in model scale. However, for design of structure elements like the wave wall on the top of a caisson the wave load sampling frequency must be much higher, in the order of 1000 Hz in the model. Elastic-plastic deformations of foundation and structure were not included in the analysis....

  1. How important is diversity for capturing environmental-change responses in ecosystem models?

    DEFF Research Database (Denmark)

    Prowe, Friederike; Pahlow, M.; Dutkiewicz, S.

    2014-01-01

    Marine ecosystem models used to investigate how global change affects ocean ecosystems and their functioning typically omit pelagic plankton diversity. Diversity, however, may affect functions such as primary production and their sensitivity to environmental changes. Here we use a global ocean...... mixing causes diversity and primary-production changes that turn out to be largely independent of the number of coexisting phytoplankton subtypes. The way diversity is represented in the model provides a small number of niches with respect to nutrient use in accordance with the PFTs defined in the model...

  2. Markov Switching Autoregressive Conditional Heteroscedasticity (SWARCH) Model to Detect Financial Crisis in Indonesia Based on Import and Export Indicators

    Science.gov (United States)

    Sugiyanto; Zukhronah, Etik; Susanti, Yuliana; Rahma Dwi, Sisca

    2017-06-01

    A country is said to be a crisis when the financial system is experiencing a disruption that affects systems that can not function efficiently. The performance efficiency of macroeconomic indicators especially in imports and exports can be used to detect the financial crisis in Indonesia. Based on the import and export indicators from 1987 to 2015, the movement of these indicators can be modelled using SWARCH three states. The results showed that SWARCH (3,1) model was able to detect the crisis that occurred in Indonesia in 1997 and 2008. Using this model, it can be concluded that Indonesia is prone to financial crisis in 2016.

  3. Group Decision-making Models on Determining the Importance Ratings of Technical Characteristics

    Institute of Scientific and Technical Information of China (English)

    GUO Qian; PU Yun; ZHANG Jing

    2011-01-01

    Determining the importance ratings of technical characteristics is a typical group decision-making process. The linguistic-based approach can effectively manage the imprecise and multi-granularity information i;n quality function deployment and facilitate decision-making in deriving the importance ratings. Based on the linguistic weighted averaging (LWA) operator and the linguistic hybrid averaging (LHA) operator, a practical approach is proposed to first aggregate the individual judgments into a collective value for each technical characteristic under linguistic environment, and then measure the deviation degree of linguistic variables to obtain the importance ratings of technical characteristics. A case study shows the application of the proposed method.

  4. Management modelling behaviour: An important prerequisite for the implementation of business ethics

    Directory of Open Access Journals (Sweden)

    E. van Zyl

    2001-08-01

    Full Text Available Researchers agree that ethics and ethical behaviour have become two of the most important topics of the new millennium. Reasons for this can include changing business conditions as well as the growing public demand for quality services, reasonable prices and honest treatment. Furthermore, the present wave of corruption in South African business makes it important to focus on management-related factors that seem to influence employees’ decisions to behave ethically at work. These phenomena will be used as a basis to make practical suggestions on how to improve the situation.

  5. DEVELOPMENT PROBABILITY-LINGUISTIC MODELS VULNERABILITY ASSESSMENT OF AVIATION SECURITY IMPORTANT TECHNICAL FACILITIES

    National Research Council Canada - National Science Library

    2016-01-01

    ... are justified, and the assessment problem of the protected object vulnerability is formulated. The main advantage of the developed model is the extensive opportunities of formalization of diverse information on the security status of the object...

  6. Implementing integrated models of care: the importance of the macro-level context.

    Science.gov (United States)

    Ashton, Toni

    2015-01-01

    Reports of how different countries are responding to the need to develop more integrated health and social care services for older adults can provide useful lessons for other health systems. However an understanding of how the wider structural, political, economic and cultural context affects implementation of these models of care is essential when considering the potential for models to be scaled up or transferred to other jurisdictions.

  7. Patch test with preservatives

    Directory of Open Access Journals (Sweden)

    Kar Sumit

    1992-01-01

    Full Text Available Of the 705 patients patch tested between March 88 to March 91, 317 were tested for sensitivity to preservatives with antigens obtained from Chemo technique AB, Sweden. Paraben was the commonest sensitizer (22.4% followed by Groton B K (8.1% and Triclosan (6.5%. We stress the need to consider these allergens as source of dermatitis and advocate complete labelling of topical preparations marketed.

  8. Fertility preservation options in breast cancer patients.

    Science.gov (United States)

    Kasum, Miro; von Wolff, Michael; Franulić, Daniela; Čehić, Ermin; Klepac-Pulanić, Tajana; Orešković, Slavko; Juras, Josip

    2015-01-01

    The purpose of this review is to analyse current options for fertility preservation in young women with breast cancer (BC). Considering an increasing number of BC survivors, owing to improvements in cancer treatment and delaying of childbearing, fertility preservation appears to be an important issue. Current fertility preservation options in BC survivors range from well-established standard techniques to experimental or investigational interventions. Among the standard options, random-start ovarian stimulation protocol represents a new technique, which significantly decreases the total time of the in vitro fertilisation cycle. However, in patients with oestrogen-sensitive tumours, stimulation protocols using aromatase inhibitors are currently preferred over tamoxifen regimens. Cryopreservation of embryos and oocytes are nowadays deemed the most successful techniques for fertility preservation in BC patients. GnRH agonists during chemotherapy represent an experimental method for fertility preservation due to conflicting long-term outcome results regarding its safety and efficacy. Cryopreservation of ovarian tissue, in vitro maturation of immature oocytes and other strategies are considered experimental and should only be offered within the context of a clinical trial. An early pretreatment referral to reproductive endocrinologists and oncologists should be suggested to young BC women at risk of infertility, concerning the risks and benefits of fertility preservation options.

  9. E-space preservation.

    Science.gov (United States)

    Sonis, Andrew; Ackerman, Marc

    2011-11-01

    To determine the relationship of E-space preservation with lingual holding arches to mandibular permanent second molar impaction. Two hundred consecutively treated patients undergoing nonextraction treatment for incisor crowding were entered into the study. Lower incisor crowding was assessed by the Little Irregularity Index. Treatment involved E-space preservation via a passive lingual arch placed prior to exfoliation of the second primary molar. Panoramic and cephalometric radiographs were analyzed for any significant relationship of mandibular permanent second molar impaction relative to molar angulation, spacing, growth pattern, and skeletal relationships. Twenty-nine patients had at least one impacted second molar (14.5%). Of a possible 400 mandibular second molars, 34 were determined to be impacted (8.5%). Only the mandibular first molar-second molar angulation was found to be significant (P < .001). Pretreatment intermolar angulation of 24 degrees had a positive predictive value of 1. Impaction of permanent second mandibular molars in patients undergoing nonextraction via E-space preservation with a passive lingual arch is 10 to 20 times more prevalent than that observed in the general population. Risk of impaction is best predicted by the pretreatment intermolar angulation between first and second permanent mandibular molars.

  10. A review of successful aging models: Proposing proactive coping as an important additional strategy

    NARCIS (Netherlands)

    Ouwehand, C.; Ridder, D.T.D. de; Bensing, J.

    2007-01-01

    Successful aging is an important concept, and one that has been the subject of much research. During the last 15 years, the emphasis of this research has shifted from formulating criteria for successful aging to describing the processes involved in successful aging. The main purpose of the present a

  11. A review of successful aging models: proposing proactive coping as an important additional strategy.

    NARCIS (Netherlands)

    Ouwehand, C.; Ridder, D.T.D. de; Bensing, J.M.

    2007-01-01

    Successful aging is an important concept, and one that has been the subject of much research. During the last 15 years, the emphasis of this research has shifted from formulating criteria for successful aging to describing the processes involved in successful aging. The main purpose of the present a

  12. On the importance of aerosol nitrate over Europe : data analysis and modelling

    NARCIS (Netherlands)

    Schaap, M.

    2003-01-01

    The central theme of this thesis is the nitrate content of aerosols (or particulate matter (PM)). Aerosols play an important role in the climate system by scattering and/or absorbing solar radiation. In the last decades research has been devoted to quantify the radiative forcing of aerosols on clima

  13. Tidal marsh susceptibility to sea-level rise: importance of local-scale models

    Science.gov (United States)

    Thorne, Karen M.; Buffington, Kevin J.; Elliott-Fisk, Deborah L.; Takekawa, John Y.

    2015-01-01

    Increasing concern over sea-level rise impacts to coastal tidal marsh ecosystems has led to modeling efforts to anticipate outcomes for resource management decision making. Few studies on the Pacific coast of North America have modeled sea-level rise marsh susceptibility at a scale relevant to local wildlife populations and plant communities. Here, we use a novel approach in developing an empirical sea-level rise ecological response model that can be applied to key management questions. Calculated elevation change over 13 y for a 324-ha portion of San Pablo Bay National Wildlife Refuge, California, USA, was used to represent local accretion and subsidence processes. Next, we coupled detailed plant community and elevation surveys with measured rates of inundation frequency to model marsh state changes to 2100. By grouping plant communities into low, mid, and high marsh habitats, we were able to assess wildlife species vulnerability and to better understand outcomes for habitat resiliency. Starting study-site conditions were comprised of 78% (253-ha) high marsh, 7% (30-ha) mid marsh, and 4% (18-ha) low marsh habitats, dominated by pickleweed Sarcocornia pacifica and cordgrass Spartina spp. Only under the low sea-level rise scenario (44 cm by 2100) did our models show persistence of some marsh habitats to 2100, with the area dominated by low marsh habitats. Under mid (93 cm by 2100) and high sea-level rise scenarios (166 cm by 2100), most mid and high marsh habitat was lost by 2070, with only 15% (65 ha) remaining, and a complete loss of these habitats by 2080. Low marsh habitat increased temporarily under all three sea-level rise scenarios, with the peak (286 ha) in 2070, adding habitat for the endemic endangered California Ridgway’s rail Rallus obsoletus obsoletus. Under mid and high sea-level rise scenarios, an almost complete conversion to mudflat occurred, with most of the area below mean sea level. Our modeling assumed no marsh migration upslope due to human

  14. Consistently modeling the same movement strategy is more important than model skill level in observational learning contexts.

    Science.gov (United States)

    Buchanan, John J; Dean, Noah

    2014-02-01

    The experiment undertaken was designed to elucidate the impact of model skill level on observational learning processes. The task was bimanual circle tracing with a 90° relative phase lead of one hand over the other hand. Observer groups watched videos of either an instruction model, a discovery model, or a skilled model. The instruction and skilled model always performed the task with the same movement strategy, the right-arm traced clockwise and the left-arm counterclockwise around circle templates with the right-arm leading. The discovery model used several movement strategies (tracing-direction/hand-lead) during practice. Observation of the instruction and skilled model provided a significant benefit compared to the discovery model when performing the 90° relative phase pattern in a post-observation test. The observers of the discovery model had significant room for improvement and benefited from post-observation practice of the 90° pattern. The benefit of a model is found in the consistency with which that model uses the same movement strategy, and not within the skill level of the model. It is the consistency in strategy modeled that allows observers to develop an abstract perceptual representation of the task that can be implemented into a coordinated action. Theoretically, the results show that movement strategy information (relative motion direction, hand lead) and relative phase information can be detected through visual perception processes and be successfully mapped to outgoing motor commands within an observational learning context.

  15. Importance of a 3D forward modeling tool for surface wave analysis methods

    Science.gov (United States)

    Pageot, Damien; Le Feuvre, Mathieu; Donatienne, Leparoux; Philippe, Côte; Yann, Capdeville

    2016-04-01

    Since a few years, seismic surface waves analysis methods (SWM) have been widely developed and tested in the context of subsurface characterization and have demonstrated their effectiveness for sounding and monitoring purposes, e.g., high-resolution tomography of the principal geological units of California or real time monitoring of the Piton de la Fournaise volcano. Historically, these methods are mostly developed under the assumption of semi-infinite 1D layered medium without topography. The forward modeling is generally based on Thomson-Haskell matrix based modeling algorithm and the inversion is driven by Monte-Carlo sampling. Given their efficiency, SWM have been transfered to several scale of which civil engineering structures in order to, e.g., determine the so-called V s30 parameter or assess other critical constructional parameters in pavement engineering. However, at this scale, many structures may often exhibit 3D surface variations which drastically limit the efficiency of SWM application. Indeed, even in the case of an homogeneous structure, 3D geometry can bias the dispersion diagram of Rayleigh waves up to obtain discontinuous phase velocity curves which drastically impact the 1D mean velocity model obtained from dispersion inversion. Taking advantages of high-performance computing center accessibility and wave propagation modeling algorithm development, it is now possible to consider the use of a 3D elastic forward modeling algorithm instead of Thomson-Haskell method in the SWM inversion process. We use a parallelized 3D elastic modeling code based on the spectral element method which allows to obtain accurate synthetic data with very low numerical dispersion and a reasonable numerical cost. In this study, we choose dike embankments as an illustrative example. We first show that their longitudinal geometry may have a significant effect on dispersion diagrams of Rayleigh waves. Then, we demonstrate the necessity of 3D elastic modeling as a forward

  16. Animal models and their importance to human physiological responses in microgravity

    Science.gov (United States)

    Tipton, C. M.

    1996-01-01

    Two prominent theories to explain the physiological effects of microgravity relate to the cascade of changes associated with the cephalic shifts of fluids and the absence of tissue deformation forces. One-g experiments for humans used bed rest and the head-down tilt (HDT) method, while animal experiments have been conducted using the tail-suspended, head-down, and hindlimbs non-weightbearing model. Because of the success of the HDT approach with rats to simulate the gravitational effects on the musculoskeletal system exhibited by humans, the same model has been used to study the effects of gravity on the cardiopulmonary systems of humans and other vertebrates. Results to date indicate the model is effective in producing comparable changes associated with blood volume, erythropoiesis, cardiac mass, baroreceptor responsiveness, carbohydrate metabolism, post-flight VO2max, and post-flight cardiac output during exercise. Inherent with these results is the potential of the model to be useful in investigating responsible mechanisms. The suspension model has promise in understanding the capillary blood PO2 changes in space as well as the arterial PO2 changes in subjects participating in a HDT experiment. However, whether the model can provide insights on the up-or-down regulation of adrenoreceptors remains to be determined, and many investigators believe the HDT approach should not be followed to study gravitational influences on pulmonary function in either humans or animals. It was concluded that the tail-suspended animal model had sufficient merit to study in-flight and post-flight human physiological responses and mechanisms.

  17. Mathematical modeling of drying of potato slices in a forced convective dryer based on important parameters.

    Science.gov (United States)

    Naderinezhad, Samira; Etesami, Nasrin; Poormalek Najafabady, Arefe; Ghasemi Falavarjani, Majid

    2016-01-01

    The effect of air temperature, air velocity, and sample shapes (circle and square with the same cross-sectional area) on kinetic drying of potato slices in a tunnel dryer was investigated experimentally and a suitable drying model was developed. The experiments of drying of potato slices were conducted at an air temperature of 45-70°C with an air velocity 1.60 and 1.81 m sec(-1). Results showed that drying temperature was the most effective parameter in the drying rate. The influence of air velocity was more profound in low temperature. The time for drying square slices was lower compared to the circle ones. Furthermore, drying data were fitted to different empirical models. Among the models, Midilli-Kucuk was the best to explain the single layer drying of potato slices. The parameters of this model were determined as functions of air velocity and temperature by multiple regression analysis for circle and square slices. Various statistical parameters were examined for evaluating the model.

  18. On the importance of modelling the internal spatial dynamics of biological cells.

    Science.gov (United States)

    Sayyid, Faiz; Kalvala, Sara

    2016-07-01

    Spatial effects such as cell shape have very often been considered negligible in models of cellular pathways, and many existing simulation infrastructures do not take such effects into consideration. Recent experimental results are reversing this judgement by showing that very small spatial variations can make a big difference in the fate of a cell. This is particularly the case when considering eukaryotic cells, which have a complex physical structure and many subtle control mechanisms, but bacteria are also interesting for the huge variation in shape both between species and in different phases of their lifecycle. In this work we perform simulations that measure the effect of three common bacterial shapes on the behaviour of model cellular pathways. To perform these experiments we develop ReDi-Cell, a highly scalable GPGPU cell simulation infrastructure for the modelling of cellular pathways in spatially detailed environments. ReDi-Cell is validated against known-good simulations, prior to its use in new work. We then use ReDi-Cell to conduct novel experiments that demonstrate the effect that three common bacterial shapes (Cocci, Bacilli and Spirilli) have on the behaviour of model cellular pathways. Pathway wavefront shape, pathway concentration gradients, and chemical species distribution are measured in the three different shapes. We also quantify the impact of internal cellular clutter on the same pathways. Through this work we show that variations in the shape or configuration of these common cell shapes alter model cell behaviour.

  19. Important issues facing model-based approaches to tunneling transport in molecular junctions

    CERN Document Server

    Baldea, Ioan

    2015-01-01

    Extensive studies on thin films indicated a generic cubic current-voltage $I-V$ dependence as a salient feature of charge transport by tunneling. A quick glance at $I-V$ data for molecular junctions suggests a qualitatively similar behavior. This would render model-based studies almost irrelevant, since, whatever the model, its parameters can always be adjusted to fit symmetric (asymmetric) $I-V$ curves characterized by two (three) expansion coefficients. Here, we systematically examine popular models based on tunneling barrier or tight-binding pictures and demonstrate that, for a quantitative description at biases of interest ($V$ slightly higher than the transition voltage $V_t$), cubic expansions do not suffice. A detailed collection of analytical formulae as well as their conditions of applicability are presented to facilitate experimentalists colleagues to process and interpret their experimental data by obtained by measuring currents in molecular junctions. We discuss in detail the limits of applicabili...

  20. On the importance of observational data properties when assessing regional climate model performance of extreme precipitation

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Sørup, Hjalte Jomo Danielsen; Christensen, Ole Bøssing

    2013-01-01

    In recent years, there has been an increase in the number of climate studies addressing changes in extreme precipitation. A common step in these studies involves the assessment of the climate model performance. This is often measured by comparing climate model output with observational data....... In the majority of such studies the characteristics and uncertainties of the observational data are neglected. This study addresses the influence of using different observational datasets to assess the climate model performance. Four different datasets covering Denmark using different gauge systems and comprising...... both networks of point measurements and gridded datasets are considered. Additionally, the influence of using different performance indices and metrics is addressed. A set of indices ranging from mean to extreme precipitation properties is calculated for all the datasets. For each of the observational...

  1. Mathematical modelling of methanogenic reactor start-up: Importance of volatile fatty acids degrading population.

    Science.gov (United States)

    Jabłoński, Sławomir J; Łukaszewicz, Marcin

    2014-12-01

    Development of balanced community of microorganisms is one of the obligatory for stable anaerobic digestion. Application of mathematical models might be helpful in development of reliable procedures during the process start-up period. Yet, the accuracy of forecast depends on the quality of input and parameters. In this study, the specific anaerobic activity (SAA) tests were applied in order to estimate microbial community structure. Obtained data was applied as input conditions for mathematical model of anaerobic digestion. The initial values of variables describing the amount of acetate and propionate utilizing microorganisms could be calculated on the basis of SAA results. The modelling based on those optimized variables could successfully reproduce the behavior of a real system during the continuous fermentation.

  2. The importance of behavior theory in control system modeling of physical activity sensor data.

    Science.gov (United States)

    Riley, William T; Martin, Cesar A; Rivera, Daniel E

    2014-01-01

    Among health behaviors, physical activity has the most extensive record of research using passive sensors. Control systems and other system dynamic approaches have long been considered applicable for understanding human behavior, but only recently has the technology provided the precise and intensive longitudinal data required for these analytic approaches. Although sensors provide intensive data on the patterns and variations of physical activity over time, the influences of these variations are often unmeasured. Health behavior theories provide an explanatory framework of the putative mediators of physical activity changes. Incorporating the intensive longitudinal measurement of these theoretical constructs is critical to improving the fit of control system model of physical activity and for advancing behavioral theory. Theory-based control models also provide guidance on the nature of the controllers which serve as the basis for just-in-time adaptive interventions based on these control system models.

  3. Self-potentials in partially saturated media: the importance of explicit modeling of electrode effects

    CERN Document Server

    Jougnot, D

    2013-01-01

    Self-potential (SP) data are of interest to vadose zone hydrology because of their direct sensitivity to water flow and ionic transport. There is unfortunately little consensus in the literature about how to best model SP data under partially saturated conditions and different approaches (often supported by one laboratory data set alone) have been proposed. We argue herein that this lack of agreement can largely be traced to electrode effects that have not been properly taken into account. A series of drainage and imbibition experiments are considered, in which we find that previously proposed approaches to remove electrode effects are unlikely to provide adequate corrections. Instead, we explicitly model the electrode effects together with classical SP contributions using a flow and transport model. The simulated data agree overall with the observed SP signals and allow decomposing the different signal contributions to analyze them separately. By reviewing other published experimental data, we suggest that m...

  4. Plasmaspheric electron densities: the importance in modelling radiation belts and in SSA operation

    Science.gov (United States)

    Lichtenberger, János; Jorgensen, Anders; Koronczay, Dávid; Ferencz, Csaba; Hamar, Dániel; Steinbach, Péter; Clilverd, Mark; Rodger, Craig; Juhász, Lilla; Sannikov, Dmitry; Cherneva, Nina

    2016-04-01

    The Automatic Whistler Detector and Analyzer Network (AWDANet, Lichtenberger et al., J. Geophys. Res., 113, 2008, A12201, doi:10.1029/2008JA013467) is able to detect and analyze whistlers in quasi-realtime and can provide equatorial electron density data. The plasmaspheric electron densities are key parameters for plasmasphere models in Space Weather related investigations, particularly in modeling charged particle accelerations and losses in Radiation Belts. The global AWDANet detects millions of whistlers in a year. The network operates since early 2002 with automatic whistler detector capability and it has been recently completed with automatic analyzer capability in PLASMON (http://plasmon.elte.hu, Lichtenberger et al., Space Weather Space Clim. 3 2013, A23 DOI: 10.1051/swsc/2013045.) Eu FP7-Space project. It is based on a recently developed whistler inversion model (Lichtenberger, J. J. Geophys. Res., 114, 2009, A07222, doi:10.1029/2008JA013799), that opened the way for an automated process of whistler analysis, not only for single whistler events but for complex analysis of multiple-path propagation whistler groups. The network operates in quasi real-time mode since mid-2014, fifteen stations provide equatorial electron densities that are used as inputs for a data assimilative plasmasphere model but they can also be used directly in space weather research and models. We have started to process the archive data collected by AWDANet stations since 2002 and in this paper we present the results of quasi-real-time and off-line runs processing whistlers from quiet and disturb periods. The equatorial electron densities obtained by whistler inversion are fed into the assimilative model of the plasmasphere providing a global view of the region for processed the periods

  5. Modified release itraconazole amorphous solid dispersion to treat Aspergillus fumigatus: importance of the animal model selection.

    Science.gov (United States)

    Maincent, Julien P; Najvar, Laura K; Kirkpatrick, William R; Huang, Siyuan; Patterson, Thomas F; Wiederhold, Nathan P; Peters, Jay I; Williams, Robert O

    2017-02-01

    Previously, modified release itraconazole in the form of a melt-extruded amorphous solid dispersion based on a pH dependent enteric polymer combined with hydrophilic additives (HME-ITZ), exhibited improved in vitro dissolution properties. These properties agreed with pharmacokinetic results in rats showing high and sustained itraconazole (ITZ) systemic levels. The objective of the present study was to better understand the best choice of rodent model for evaluating the pharmacokinetic and efficacy of this orally administered modified release ITZ dosage form against invasive Aspergillus fumigatus. A mouse model and a guinea pig model were investigated and compared to results previously published. In the mouse model, despite similar levels as previously reported values, plasma and lung levels were variable and fungal burden was not statistically different for placebo controls, HME-ITZ and Sporanox(®) (ITZ oral solution). This study demonstrated that the mouse model is a poor choice for studying modified release ITZ dosage forms based on pH dependent enteric polymers due to low fluid volume available for dissolution and low intestinal pH. To the contrary, guinea pig was a suitable model to evaluate modified release ITZ dosage forms. Indeed, a significant decrease in lung fungal burden as a result of high and sustained ITZ tissue levels was measured. Sufficiently high intestinal pH and fluids available for dissolution likely facilitated the dissolution process. Despite high ITZ tissue level, the primary therapeutic agent voriconazole exhibited an even more pronounced decrease in fungal burden due to its reported higher clinical efficacy specifically against Aspergillus fumigatus.

  6. The iconographic model of the Minerva from Collippo and its historic importance

    Directory of Open Access Journals (Sweden)

    Virgílio Hipólito Correia

    2014-12-01

    Full Text Available A statue head representing Minerva from the ancient Collippo (S. Sebastião do Freixo, Batalha is studied and its iconographic model is identified in a similar piece from the temple of Apollo Sosianus in Rome; other pieces of the same model are identified.It is proposed that this piece represents a remain of an intervention in the forum of the ancient town probably dating from the Claudio‑neronian period and its relation to similar processes occurring in the capital of the province of Lusitania is discussed.http://dx.doi.org/10.14195/2183-1718_66_16

  7. DIAGNOSIS IMPORTANCE OF RURAL DEVELOPMENT OF A MODEL AGROFORESTAL IN PEASANT COMMUNITIES OF SIERRA DE HUAUTLA

    OpenAIRE

    Miguel Uribe-Gómez; Artemio Cruz-León; Dionicio Juárez-Ramón; Alejandro Lara-Bueno; José L. Romo-Lozano; Ramón Valdivia-Alcalá; Marcos Portillo-Vázquez

    2015-01-01

    Family agricultural is socioeconomically important in rural areas, but in Mexico, from the 80's this production system presents social stagnation. This type of agriculture presents a dynamic reality in the interests of each producer and limiting access to factors of production (land, labor and capital). In this investigation a methodology for analysis and diagnosis of production systems in rural areas, in two communities in the Country Sierra de Huautla Tepalcingo, Morelos, Mexico was applied...

  8. Contamination versus preservation of cosmetics

    DEFF Research Database (Denmark)

    Lundov, Michael Dyrgaard; Moesby, Lise; Zachariae, Claus

    2009-01-01

    cosmetics. In order to avoid contamination of cosmetics, the manufacturers add preservatives to their products. In the EU and the USA, cosmetics are under legislation and all preservatives must be safety evaluated by committees. There are several different preservatives available but the cosmetic market...... is dominated by a few preservatives: parabens, formaldehyde, formaldehyde releasers, and methylchloroisothiazolinone/methylisothiazolinone. Allergy to preservatives is one of the main reasons for contact eczema caused by cosmetics. Concentration of the same preservative in similar products varies greatly......, and this may indicate that some cosmetic products are over preserved. As development and elicitation of contact allergy is dose dependent, over preservation of cosmetics potentially leads to increased incidences of contact allergy. Very few studies have investigated the antimicrobial efficiency...

  9. Important Physiological Parameters and Physical Activity Data for Evaluating Exposure Modeling Performance: a Synthesis

    Science.gov (United States)

    The purpose of this report is to develop a database of physiological parameters needed for understanding and evaluating performance of the APEX and SHEDS exposure/intake dose rate model used by the Environmental Protection Agency (EPA) as part of its regulatory activities. The A...

  10. An Ecological Risk Model for Early Childhood Anxiety: The Importance of Early Child Symptoms and Temperament

    Science.gov (United States)

    Mian, Nicholas D.; Wainwright, Laurel; Briggs-Gowan, Margaret J.; Carter, Alice S.

    2011-01-01

    Childhood anxiety is impairing and associated with later emotional disorders. Studying risk factors for child anxiety may allow earlier identification of at-risk children for prevention efforts. This study applied an ecological risk model to address how early childhood anxiety symptoms, child temperament, maternal anxiety and depression symptoms,…

  11. Numerical considerations for Lagrangian stochastic dispersion models: Eliminating rogue trajectories, and the importance of numerical accuracy

    Science.gov (United States)

    When Lagrangian stochastic models for turbulent dispersion are applied to complex flows, some type of ad hoc intervention is almost always necessary to eliminate unphysical behavior in the numerical solution. This paper discusses numerical considerations when solving the Langevin-based particle velo...

  12. Importance of interfaces in governing thermal transport in composite materials: modeling and experimental perspectives.

    Science.gov (United States)

    Roy, Ajit K; Farmer, Barry L; Varshney, Vikas; Sihn, Sangwook; Lee, Jonghoon; Ganguli, Sabyasachi

    2012-02-01

    Thermal management in polymeric composite materials has become increasingly critical in the air-vehicle industry because of the increasing thermal load in small-scale composite devices extensively used in electronics and aerospace systems. The thermal transport phenomenon in these small-scale heterogeneous systems is essentially controlled by the interface thermal resistance because of the large surface-to-volume ratio. In this review article, several modeling strategies are discussed for different length scales, complemented by our experimental efforts to tailor the thermal transport properties of polymeric composite materials. Progress in the molecular modeling of thermal transport in thermosets is reviewed along with a discussion on the interface thermal resistance between functionalized carbon nanotube and epoxy resin systems. For the thermal transport in fiber-reinforced composites, various micromechanics-based analytical and numerical modeling schemes are reviewed in predicting the transverse thermal conductivity. Numerical schemes used to realize and scale the interface thermal resistance and the finite mean free path of the energy carrier in the mesoscale are discussed in the frame of the lattice Boltzmann-Peierls-Callaway equation. Finally, guided by modeling, complementary experimental efforts are discussed for exfoliated graphite and vertically aligned nanotubes based composites toward improving their effective thermal conductivity by tailoring interface thermal resistance.

  13. Comparing Modeled and Measured Mercury Speciation in Contaminated Groundwater: Importance of Dissolved Organic Matter Composition.

    Science.gov (United States)

    Richard, Jan-Helge; Bischoff, Cornelia; Biester, Harald

    2016-07-19

    In addition to analytical speciation, reliable Hg species modeling is crucial for predicting the mobility and toxicity of Hg, but geochemical speciation codes have not yet been tested for their prediction accuracy. Our study compares analyses of Hg species in highly Hg-contaminated groundwater (Hgtot: 0.02-4 μmol·L(-1)) at three sites with predictions of Hg speciation obtained from three geochemical codes (WHAM, Visual MINTEQ, PHREEQC) with and without implementation of Hg complexation by dissolved organic matter (DOM). Samples were analyzed for chemical composition, elemental, inorganic, and DOM-bound Hg (Hg(0), Hginorg, HgDOM). Hg-DOM complexation was modeled using three approaches: binding to humic/fulvic acids, binding to thiol-groups, or a combination of both. Results of Hg(0) modeling were poor in all scenarios. Prediction accuracy for Hginorg and HgDOM strongly depended on the assumed DOM composition. Best results were achieved when weaker binding sites, simulated by WHAMs DOM submodel, were combined with strongly binding thiol groups. Indications were found that thiol-DOM ratios in groundwater are likely to be lower than in surface water, highlighting the need for analytical thiol quantification in groundwater DOM. This study shows that DOM quality is a crucial parameter for prediction of Hg speciation in groundwater by means of geochemical modeling.

  14. On the importance of measurement error correlations in data assimilation for integrated hydrological models

    Science.gov (United States)

    Camporese, Matteo; Botto, Anna

    2017-04-01

    Data assimilation is becoming increasingly popular in hydrological and earth system modeling, as it allows us to integrate multisource observation data in modeling predictions and, in doing so, to reduce uncertainty. For this reason, data assimilation has been recently the focus of much attention also for physically-based integrated hydrological models, whereby multiple terrestrial compartments (e.g., snow cover, surface water, groundwater) are solved simultaneously, in an attempt to tackle environmental problems in a holistic approach. Recent examples include the joint assimilation of water table, soil moisture, and river discharge measurements in catchment models of coupled surface-subsurface flow using the ensemble Kalman filter (EnKF). One of the typical assumptions in these studies is that the measurement errors are uncorrelated, whereas in certain situations it is reasonable to believe that some degree of correlation occurs, due for example to the fact that a pair of sensors share the same soil type. The goal of this study is to show if and how the measurement error correlations between different observation data play a significant role on assimilation results in a real-world application of an integrated hydrological model. The model CATHY (CATchment HYdrology) is applied to reproduce the hydrological dynamics observed in an experimental hillslope. The physical model, located in the Department of Civil, Environmental and Architectural Engineering of the University of Padova (Italy), consists of a reinforced concrete box containing a soil prism with maximum height of 3.5 m, length of 6 m, and width of 2 m. The hillslope is equipped with sensors to monitor the pressure head and soil moisture responses to a series of generated rainfall events applied onto a 60 cm thick sand layer overlying a sandy clay soil. The measurement network is completed by two tipping bucket flow gages to measure the two components (subsurface and surface) of the outflow. By collecting

  15. Image segmentation on adaptive edge-preserving smoothing

    Science.gov (United States)

    He, Kun; Wang, Dan; Zheng, Xiuqing

    2016-09-01

    Nowadays, typical active contour models are widely applied in image segmentation. However, they perform badly on real images with inhomogeneous subregions. In order to overcome the drawback, this paper proposes an edge-preserving smoothing image segmentation algorithm. At first, this paper analyzes the edge-preserving smoothing conditions for image segmentation and constructs an edge-preserving smoothing model inspired by total variation. The proposed model has the ability to smooth inhomogeneous subregions and preserve edges. Then, a kind of clustering algorithm, which reasonably trades off edge-preserving and subregion-smoothing according to the local information, is employed to learn the edge-preserving parameter adaptively. At last, according to the confidence level of segmentation subregions, this paper constructs a smoothing convergence condition to avoid oversmoothing. Experiments indicate that the proposed algorithm has superior performance in precision, recall, and F-measure compared with other segmentation algorithms, and it is insensitive to noise and inhomogeneous-regions.

  16. Creating preservation metadata from XML-metadata profiles

    Science.gov (United States)

    Ulbricht, Damian; Bertelmann, Roland; Gebauer, Petra; Hasler, Tim; Klump, Jens; Kirchner, Ingo; Peters-Kottig, Wolfgang; Mettig, Nora; Rusch, Beate

    2014-05-01

    Registration of dataset DOIs at DataCite makes research data citable and comes with the obligation to keep data accessible in the future. In addition, many universities and research institutions measure data that is unique and not repeatable like the data produced by an observational network and they want to keep these data for future generations. In consequence, such data should be ingested in preservation systems, that automatically care for file format changes. Open source preservation software that is developed along the definitions of the ISO OAIS reference model is available but during ingest of data and metadata there are still problems to be solved. File format validation is difficult, because format validators are not only remarkably slow - due to variety in file formats different validators return conflicting identification profiles for identical data. These conflicts are hard to resolve. Preservation systems have a deficit in the support of custom metadata. Furthermore, data producers are sometimes not aware that quality metadata is a key issue for the re-use of data. In the project EWIG an university institute and a research institute work together with Zuse-Institute Berlin, that is acting as an infrastructure facility, to generate exemplary workflows for research data into OAIS compliant archives with emphasis on the geosciences. The Institute for Meteorology provides timeseries data from an urban monitoring network whereas GFZ Potsdam delivers file based data from research projects. To identify problems in existing preservation workflows the technical work is complemented by interviews with data practitioners. Policies for handling data and metadata are developed. Furthermore, university teaching material is created to raise the future scientists awareness of research data management. As a testbed for ingest workflows the digital preservation system Archivematica [1] is used. During the ingest process metadata is generated that is compliant to the

  17. Constrained Graph Optimization: Interdiction and Preservation Problems

    Energy Technology Data Exchange (ETDEWEB)

    Schild, Aaron V [Los Alamos National Laboratory

    2012-07-30

    The maximum flow, shortest path, and maximum matching problems are a set of basic graph problems that are critical in theoretical computer science and applications. Constrained graph optimization, a variation of these basic graph problems involving modification of the underlying graph, is equally important but sometimes significantly harder. In particular, one can explore these optimization problems with additional cost constraints. In the preservation case, the optimizer has a budget to preserve vertices or edges of a graph, preventing them from being deleted. The optimizer wants to find the best set of preserved edges/vertices in which the cost constraints are satisfied and the basic graph problems are optimized. For example, in shortest path preservation, the optimizer wants to find a set of edges/vertices within which the shortest path between two predetermined points is smallest. In interdiction problems, one deletes vertices or edges from the graph with a particular cost in order to impede the basic graph problems as much as possible (for example, delete edges/vertices to maximize the shortest path between two predetermined vertices). Applications of preservation problems include optimal road maintenance, power grid maintenance, and job scheduling, while interdiction problems are related to drug trafficking prevention, network stability assessment, and counterterrorism. Computational hardness results are presented, along with heuristic methods for approximating solutions to the matching interdiction problem. Also, efficient algorithms are presented for special cases of graphs, including on planar graphs. The graphs in many of the listed applications are planar, so these algorithms have important practical implications.

  18. Oxygen absorbers in food preservation: a review.

    Science.gov (United States)

    Cichello, Simon Angelo

    2015-04-01

    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen impermeable package material and the quality of oxygen absorber. Ferrous iron oxides are the most reliable and commonly used oxygen absorbers within the food industry. Oxygen absorbers have been transformed from sachets of dried iron-powder to simple self-adhesive patches to accommodate any custom size, capacity and application. Oxygen concentration can be effectively lowered to 100 ppm, with applications spanning a wide range of food products and beverages across the world (i.e. bread, meat, fish, fruit, and cheese). Newer molecules that preserve packaged food materials from all forms of degradation are being developed, however oxygen absorbers remain a staple product for the preservation of food and pharmaceutical products to reduce food wastage in developed nations and increased food security in the developing & third world.

  19. Data Preservation in High Energy Physics

    CERN Document Server

    Kogler, Roman; Steder, Michael

    2011-01-01

    Data from high-energy physics experiments are collected with significant financial and human effort and are mostly unique. However, until recently no coherent strategy existed for data preservation and re-use, and many important and complex data sets have simply been lost. While the current focus is on the LHC at CERN, in the current period several important and unique experimental programs at other facilities are coming to an end, including those at HERA, b-factories and the Tevatron. To address this issue, an inter-experimental study group on HEP data preservation and long-term analysis (DPHEP) was convened at the end of 2008. The group now aims to publish a full and detailed review of the present status of data preservation in high energy physics. This contribution summarises the results of the DPHEP study group, describing the challenges of data preservation in high energy physics and the group's first conclusions and recommendations. The physics motivation for data preservation, generic computing and pre...

  20. Recent Advances in the Use of Drosophila melanogaster as a Model to Study Immunopathogenesis of Medically Important Filamentous Fungi

    Directory of Open Access Journals (Sweden)

    Georgios Hamilos

    2012-01-01

    Full Text Available Airborne opportunistic fungi, including Aspergillus and other less common saprophytic molds, have recently emerged as important causes of mortality in immunocompromised individuals. Understanding the molecular mechanisms of host-fungal interplay in robust experimental pathosystems is becoming a research priority for development of novel therapeutics to combat these devastating infections. Over the past decade, invertebrate hosts with evolutionarily conserved innate immune signaling pathways and powerful genetics, such as Drosophila melanogaster, have been employed as a means to overcome logistic restrains associated with the use mammalian models of fungal infections. Recent studies in Drosophila models of filamentous fungi demonstrated that several genes implicated in fungal virulence in mammals also play a similarly important pathogenic role in fruit flies, and important host-related aspects in fungal pathogenesis are evolutionarily conserved. In view of recent advances in Drosophila genetics, fruit flies will become an invaluable surrogate model to study immunopathogenesis of fungal diseases.

  1. Boolean modeling identifies Greatwall/MASTL as an important regulator in the AURKA network of neuroblastoma.

    Science.gov (United States)

    Dahlhaus, Meike; Burkovski, Andre; Hertwig, Falk; Mussel, Christoph; Volland, Ruth; Fischer, Matthias; Debatin, Klaus-Michael; Kestler, Hans A; Beltinger, Christian

    2016-02-01

    Aurora Kinase A (AURKA) is often overexpressed in neuroblastoma (NB) with poor outcome. The causes of AURKA overexpression in NB are unknown. Here, we describe a gene regulatory network consisting of core regulators of AURKA protein expression and activation during mitosis to identify potential causes. This network was transformed to a dynamic Boolean model. Simulated activation of the serine/threonine protein kinase Greatwall (GWL, encoded by MASTL) that attenuates the pivotal AURKA inhibitor PP2A, predicted stabilization of AURKA. Consistent with this notion, gene set enrichment analysis showed enrichment of mitotic spindle assembly genes and MYCN target genes in NB with high GWL/MASTL expression. In line with the prediction of GWL/MASTL enhancing AURKA, elevated expression of GWL/MASTL was associated with NB risk factors and poor survival of patients. These results establish Boolean network modeling of oncogenic pathways in NB as a useful means for guided discovery in this enigmatic cancer.

  2. On determining important aspects of mathematical models: Application to problems in physics and chemistry

    Science.gov (United States)

    Rabitz, Herschel

    1987-01-01

    The use of parametric and functional gradient sensitivity analysis techniques is considered for models described by partial differential equations. By interchanging appropriate dependent and independent variables, questions of inverse sensitivity may be addressed to gain insight into the inversion of observational data for parameter and function identification in mathematical models. It may be argued that the presence of a subset of dominantly strong coupled dependent variables will result in the overall system sensitivity behavior collapsing into a simple set of scaling and self similarity relations amongst elements of the entire matrix of sensitivity coefficients. These general tools are generic in nature, but herein their application to problems arising in selected areas of physics and chemistry is presented.

  3. The importance of spatial resolution and convective parameterisation in modelling soil moisture - precipitation feedbacks

    Science.gov (United States)

    Garcia-Carreras, Luis; Taylor, Christopher M.; Roberts, Malcolm; Marsham, John H.

    2017-04-01

    Soil moisture influences low-level temperature and humidity, which can strongly affect convective development. The location of convection in turn alters the soil moisture anomalies present on the following day, providing a feedback mechanism. Satellite observations show that in the tropics afternoon rainfall falls preferentially where the ground is drier than its surroundings. A large number of global weather and climate models, on the other hand, show a positive soil moisture - rainfall feedback, inconsistent with observations. This systematic bias will tend to exaggerate drought impacts in global atmospheric models, and points to missing fundamental processes in the models related to the coupling between the surface and convection. While the source of this error is still unclear, it has been hypothesized that the triggering of parameterisations of convection is excessively sensitive to low-level moisture, leading to convection initiating preferentially over wet soils. Here we quantify the soil-moisture - precipitation feedback sign using the same method as in Taylor et al. (Nature, 2012), which is now part of the ESMValTool model evaluation toolbox. We analyse multi-year global simulations using the Met Office Unified Model (MetUM) with different resolutions and representations of convection. Three simulations are run at 15 km grid-spacing with different representations of convection: 1. the standard operational MetUM parameterisation scheme, 2. 'convection permitting', where the parameterisations of shallow and deep convection are turned off, and 3. only the parameterisation of shallow convection is turned on. The use of the same resolution and setup, except for the representation of convection, allows us to exclude any effects from changing resolution. Additional simulations at 30, 50 and 150 km grid-spacings using the standard MetUM parameterisation of convection scheme are then used to explore the impact of resolution. All simulations show daytime

  4. Why Knowledge Modeling is Important for Business and for a Danish Terminology and Knowledge Bank

    DEFF Research Database (Denmark)

    Erdman Thomsen, Hanne; Madsen, Bodil Nistrup

    2011-01-01

    Businesses and organizations, including public authorities, have a growing need for organizing and handling large amounts of data. In order to manage complex knowledge, knowledge must be modeled and structured. One very powerful method used for structuring knowledge is the use of ontologies....... Businesses and organizations need efficient tools for building domain-specific ontologies and systems for managing knowledge. Most medium-sized and large Danish businesses and organizations operate in a bilingual or multilingual environment, where knowledge is transferred and stored in Danish and/or English...... the foundation for a national terminology and knowledge bank. Furthermore, I will briefly introduce our plans for teaching within the field of knowledge modeling at Copenhagen Business School, CBS....

  5. Using time-varying global sensitivity analysis to understand the importance of different uncertainty sources in hydrological modelling

    Science.gov (United States)

    Pianosi, Francesca; Wagener, Thorsten

    2016-04-01

    Simulations from environmental models are affected by potentially large uncertainties stemming from various sources, including model parameters and observational uncertainty in the input/output data. Understanding the relative importance of such sources of uncertainty is essential to support model calibration, validation and diagnostic evaluation, and to prioritize efforts for uncertainty reduction. Global Sensitivity Analysis (GSA) provides the theoretical framework and the numerical tools to gain this understanding. However, in traditional applications of GSA, model outputs are an aggregation of the full set of simulated variables. This aggregation of propagated uncertainties prior to GSA may lead to a significant loss of information and may cover up local behaviour that could be of great interest. In this work, we propose a time-varying version of a recently developed density-based GSA method, called PAWN, as a viable option to reduce this loss of information. We apply our approach to a medium-complexity hydrological model in order to address two questions: [1] Can we distinguish between the relative importance of parameter uncertainty versus data uncertainty in time? [2] Do these influences change in catchments with different characteristics? The results present the first quantitative investigation on the relative importance of parameter and data uncertainty across time. They also provide a demonstration of the value of time-varying GSA to investigate the propagation of uncertainty through numerical models and therefore guide additional data collection needs and model calibration/assessment.

  6. Mitral leaflet modeling: Importance of in vivo shape and material properties.

    Science.gov (United States)

    Stevanella, Marco; Krishnamurthy, Gaurav; Votta, Emiliano; Swanson, Julia C; Redaelli, Alberto; Ingels, Neil B

    2011-08-11

    The anterior mitral leaflet (AML) is a thin membrane that withstands high left ventricular (LV) pressure pulses 100,000 times per day. The presence of contractile cells determines AML in vivo stiffness and complex geometry. Until recently, mitral valve finite element (FE) models have neglected both of these aspects. In this study we assess their effect on AML strains and stresses, hypothesizing that these will differ significantly from those reported in literature. Radiopaque markers were sewn on the LV, the mitral annulus, and AML in sheep hearts, and their four-dimensional coordinates obtained with biplane video fluoroscopy. Employing in vivo data from three representative hearts, AML FE models were created from the marker coordinates at the end of isovolumic relaxation assumed as the unloaded reference state. AML function was simulated backward through systole, applying the measured trans-mitral pressure on AML LV surface and marker displacements on AML boundaries. Simulated AML displacements and curvatures were consistent with in vivo measurements, confirming model accuracy. AML circumferential strains were mostly tensile (1-3%), despite being compressive (-1%) near the commissures. Radial strains were compressive in the belly (-1 to -0.2%), and tensile (2-8%) near the free edge. These results differ significantly from those of previous FE models. They reflect the synergy of high tissue stiffness, which limits tensile circumferential strains, and initial compound curvature, which forces LV pressure to compress AML radially. The obtained AML shape may play a role not only in preventing mitral regurgitation, but also in optimizing LV outflow fluid dynamics.

  7. The importance of nature's invisible fabric: food web structure mediates modeled responses to river restoration

    Science.gov (United States)

    Bellmore, R.; Benjamin, J.; Newsom, M.; Bountry, J.; Dombroski, D.

    2016-12-01

    Restoration is frequently aimed at the recovery of target species, but also influences the larger food web in which these species participate. Effects of restoration on this broader network of organisms can influence target species both directly and indirectly via changes in energy flow through food webs. To help incorporate these complexities into river restoration planning we constructed a food web model that links river food web dynamics to in-stream physical habitat and riparian vegetation conditions. We present an application of this model to the Methow River, Washington (USA), a location of on-going restoration aimed at recovering salmon. Three restoration strategies were simulated: riparian vegetation restoration, nutrient augmentation via salmon carcass addition, and floodplain reconnection. To explore how food web structure mediates responses to these actions, we modified the food web by adding populations of invasive aquatic snails and nonnative fish. Simulations suggest that floodplain reconnection may be a better strategy than carcass addition and vegetation planting for improving conditions for salmon in this river segment. However, modeled responses were strongly sensitive to changes in the structure of the food web. The addition of invasive snails and nonnative fishes modified pathways of energy through the food web, which negated restoration improvements. This finding illustrates that forecasting responses to restoration may require accounting for the structure of food webs, and that changes in this structure—as might be expected with the spread of invasive species—could compromise restoration outcomes. By elucidating the direct and indirect pathways by which restoration affects target species, dynamic food web models can improve restoration planning by fostering a deeper understanding of system connectedness and dynamics.

  8. Pole tide Love number - an important parameter for polar motion modeling

    Science.gov (United States)

    Kirschner, S.; Schmidt, M. G.; Seitz, F.

    2013-12-01

    The Euler-Liouville equation is the basic physical model to describe Earth rotation. It is based on the balance of angular momentum in the Earth system. The pole tide Love number is needed to characterize the rotational deformation effect, which depends on the internal structure and rheology of the Earth. There is a direct dependency between the pole tide Love number and the period and damping of the Chandler oscillation. Here we estimate the pole tide Love number on the basis of an inversion of the Euler-Liouville equation. The Earth orientation parameters are used as input parameters. They have been observed precisely over several decades by geodetic methods (C01 and C04 time series). It will be shown that the estimated pole tide Love number leads to significantly better results for polar motion compared to the original value taken from the Conventions of the International Earth Rotation and Reference System Service (IERS). Nevertheless the estimation is dependent on the input models for the subsystems (e.g. atmosphere and ocean models), applied estimation approach and time frame. These aspects are analyzed and discussed in detail.

  9. Fee-for-service as a business model of growing importance: the academic biobank experience.

    Science.gov (United States)

    McDonald, Sandra A; Sommerkamp, Kara; Egan-Palmer, Maureen; Kharasch, Karen; Holtschlag, Victoria

    2012-10-01

    Biorepositories offer tremendous scientific value to a wide variety of customer groups (academic, commercial, industrial) in their ability to deliver a centralized, standardized service model, encompassing both biospecimen storage and related laboratory services. Generally, the scientific expertise and economies of scale that are offered in centralized, properly resourced research biobanks has yielded value that has been well-recognized by universities, pharmaceutical companies, and other sponsoring institutions. However, like many facets of the economy, biobanks have been under increasing cost pressure in recent years. This has been a particular problem in the academic arena, where direct support from grant sources (both governmental and philanthropic) typically now is more difficult to secure, or provides reduced financial support, relative to previous years. One way to address this challenge is to establish or enhance a well-defined fee-for-service model which is properly calibrated to cover operational costs while still offering competitive value to users. In this model, customers are never charged for the biospecimens themselves, but rather for the laboratory services associated with them. Good communication practices, proper assessment of value, implementation of best practices, and a sound business plan are all needed for this initiative to succeed. Here we summarize our experiences at Washington University School of Medicine in the expectation they will be useful to others.

  10. The importance of health belief models in determining self-care behaviour in diabetes.

    Science.gov (United States)

    Harvey, J N; Lawson, V L

    2009-01-01

    Patients' self-care behaviours have a major role in diabetes management. Diabetes education provides the required knowledge, but despite this, self-care is often suboptimal. The degree to which patients follow advice as regards the various self-care behaviours is determined by their health beliefs (Illness Representations or Personal Models) of diabetes. Psychometric studies have tried to categorize and measure the beliefs about illness that influence patients to adhere to treatment recommendations in diabetes. Various models have been proposed to explain the relationship between beliefs and behaviour. Leventhal's Self-Regulatory Model, which takes account of the emotional as well as the objective rational response to illness, currently seems to offer the best system for identifying the determinants of patient self-care behaviour. A review of interventions indicates those based on psychological theory offer professionals the best chance of maximizing their patients' contribution to diabetes self-management and achieving improved outcomes, both glycaemic and psychosocial. Studies designed specifically to modify illness representations are now being undertaken. This brief review aims to summarize developments in this area of psychological theory over the last 20 years and the implications for promoting better self-care behaviour in diabetes.

  11. The importance of land cover change across urban-rural typologies for climate modeling.

    Science.gov (United States)

    Vargo, Jason; Habeeb, Dana; Stone, Brian

    2013-01-15

    Land cover changes affect local surface energy balances by changing the amount of solar energy reflected, the magnitude and duration over which absorbed energy is released as heat, and the amount of energy that is diverted to non-heating fluxes through evaporation. However, such local influences often are only crudely included in climate modeling exercises, if at all. A better understanding of local land conversion dynamics can serve to inform inputs for climate models and increase the role for land use planning in climate management policy. Here we present a new approach for projecting and incorporating metropolitan land cover change into mesoscale climate and other environmental assessment models. Our results demonstrate the relative contributions of different land development patterns to land cover change and conversion and suggest that regional growth management strategies serving to increase settlement densities over time can have a significant influence on the rate of deforestation per unit of population growth. Employing the approach presented herein, the impacts of land conversion on climate change and on parallel environmental systems and services, such as ground water recharge, habitat provision, and food production, may all be investigated more closely and managed through land use planning. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. PCBs in the Arctic atmosphere: determining important driving forces using a global atmospheric transport model

    Directory of Open Access Journals (Sweden)

    C. L. Friedman

    2015-11-01

    Full Text Available We present a spatially and temporally resolved global atmospheric PCB model, driven by meteorological data, that is skilled at simulating mean atmospheric PCB concentrations and seasonal cycles in the Northern Hemisphere mid-latitudes, and mean Arctic concentrations. However, the model does not capture the observed Arctic summer maximum in atmospheric PCBs. We use the model to estimate global budgets for the International Council for the Exploration of the Sea 7 PCBs, and demonstrate that congeners that deposit more readily show lower potential for long-range transport, consistent with a recently-described "differential removal hypothesis" regarding the hemispheric transport of PCBs. Using sensitivity simulations to assess processes within, outside, or transport to the Arctic, we examine the influence of climate- and emissions-driven processes on Arctic concentrations and their effect on improving the simulated Arctic seasonal cycle. We find evidence that processes occurring outside the Arctic have a greater influence on Arctic atmospheric PCB levels than processes that occur within the Arctic. Our simulations suggest that re-emissions from sea ice melting or from the Arctic Ocean during summer would have to be unrealistically high in order to capture observed temporal trends of PCBs in the Arctic atmosphere. We conclude that mid-latitude processes are likely to have a greater effect on the Arctic under global change scenarios than re-emissions within the Arctic.

  13. Phase diagram and spin correlations of the Kitaev-Heisenberg model: Importance of quantum effects

    Science.gov (United States)

    Gotfryd, Dorota; Rusnačko, Juraj; Wohlfeld, Krzysztof; Jackeli, George; Chaloupka, Jiří; Oleś, Andrzej M.

    2017-01-01

    We explore the phase diagram of the Kitaev-Heisenberg model with nearest neighbor interactions on the honeycomb lattice using the exact diagonalization of finite systems combined with the cluster mean field approximation, and supplemented by the insights from analytic approaches: the linear spin-wave and second-order perturbation theories. This study confirms that by varying the balance between the Heisenberg and Kitaev term, frustrated exchange interactions stabilize in this model either one of four phases with magnetic long range order: Néel phase, ferromagnetic phase, and two other phases with coexisting antiferromagnetic and ferromagnetic bonds, zigzag and stripy phase, or one of two distinct spin-liquid phases. Out of these latter disordered phases, the one with ferromagnetic Kitaev interactions has a substantially broader range of stability as the neighboring competing ordered phases, ferromagnetic and stripy, have very weak quantum fluctuations. Focusing on the quantum spin-liquid phases, we study spatial spin correlations and dynamic spin structure factor of the model by the exact diagonalization technique, and discuss the evolution of gapped low-energy spin response across the quantum phase transitions between the disordered spin liquid and phases with long range magnetic order.

  14. Modeling organic aerosols during MILAGRO: importance of biogenic secondary organic aerosols

    Directory of Open Access Journals (Sweden)

    A. Hodzic

    2009-09-01

    Full Text Available The meso-scale chemistry-transport model CHIMERE is used to assess our understanding of major sources and formation processes leading to a fairly large amount of organic aerosols – OA, including primary OA (POA and secondary OA (SOA – observed in Mexico City during the MILAGRO field project (March 2006. Chemical analyses of submicron aerosols from aerosol mass spectrometers (AMS indicate that organic particles found in the Mexico City basin contain a large fraction of oxygenated organic species (OOA which have strong correspondence with SOA, and that their production actively continues downwind of the city. The SOA formation is modeled here by the one-step oxidation of anthropogenic (i.e. aromatics, alkanes, biogenic (i.e. monoterpenes and isoprene, and biomass-burning SOA precursors and their partitioning into both organic and aqueous phases. Conservative assumptions are made for uncertain parameters to maximize the amount of SOA produced by the model. The near-surface model evaluation shows that predicted OA correlates reasonably well with measurements during the campaign, however it remains a factor of 2 lower than the measured total OA. Fairly good agreement is found between predicted and observed POA within the city suggesting that anthropogenic and biomass burning emissions are reasonably captured. Consistent with previous studies in Mexico City, large discrepancies are encountered for SOA, with a factor of 2–10 model underestimate. When only anthropogenic SOA precursors were considered, the model was able to reproduce within a factor of two the sharp increase in OOA concentrations during the late morning at both urban and near-urban locations but the discrepancy increases rapidly later in the day, consistent with previous results, and is especially obvious when the column-integrated SOA mass is considered instead of the surface concentration. The increase in the missing SOA mass in the afternoon coincides with the sharp drop in POA

  15. The Importance of High Temporal Resolution in Modeling Renewable Energy Penetration Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Nicolosi, Marco; Mills, Andrew D; Wiser, Ryan H

    2010-10-08

    Traditionally, modeling investment and dispatch problems in electricity economics has been limited by computation power. Due to this limitation, simplifications are applied. One common practice, for example, is to reduce the temporal resolution of the dispatch by clustering similar load levels. The increase of intermittent electricity from renewable energy sources (RES-E) changes the validity of this assumption. RES-E already cover a certain amount of the total demand. This leaves an increasingly volatile residual demand to be matched by the conventional power market. This paper quantifies differences in investment decisions by applying three different time-resolution residual load patterns in an investment and dispatch power system model. The model optimizes investment decisions in five year steps between today and 2030 with residual load levels for 8760, 288 and 16 time slices per year. The market under consideration is the four zone ERCOT market in Texas. The results show that investment decisions significantly differ across the three scenarios. In particular, investments into base-load technologies are substantially reduced in the high resolution scenario (8760 residual load levels) relative to the scenarios with lower temporal resolution. Additionally, the amount of RES-E curtailment and the market value of RES-E exhibit noteworthy differences.

  16. Phlebotominae of epidemiological importance in cutaneous leishmaniasis in northwestern Argentina: risk maps and ecological niche models.

    Science.gov (United States)

    Quintana, M; Salomón, O; Guerra, R; De Grosso, M Lizarralde; Fuenzalida, A

    2013-03-01

    In Argentina, 58.2% out of the 8126 Cutaneous Leishmaniasis (CL) incident cases accumulated from 1954 to 2006 were reported in the provinces of Salta and Jujuy. The aim of this study was to develop an exploratory risk map and a potential distribution map of the vector, in order to offer recommendations for CL prevention. A total of 12 079 Phlebotominae (Diptera: Psychodidae) belonging to the species Lutzomyia neivai (Pinto), Lu. migonei (França), Lu. cortelezzii (Brèthes), Lu. shannoni (Dyar), Lu. quinquefer (Dyar) and Brumptomyia spp. (França & Parrot) were captured. Potential distribution models were created for two species, Lu. neivai (incriminated vector of Leishmania braziliensis) and Lu. migonei, associated with domestic animals in Argentina and that in turn could be involved as a link between zoonotic transmission cycles and anthropozoonotic. The Maximum Entropy Modeling System (MaxEnt) was used. The Jackknife test was performed, and the 'rainfall of the driest month' was the variable that best generalized the models. Accuracy was evaluated by the area under the curve (AUC) and validated by the Cohen's kappa index. This approximation provides a new analytical resource of high potential for the prevention of the disease, in order to allocate resources properly and to develop the most suitable strategies for action.

  17. Critical analysis of the current approaches to modelling educational effectiveness : The importance of establishing a dynamic model

    NARCIS (Netherlands)

    Creemers, B. P. M.; Kyriakides, L.

    2006-01-01

    Researchers in the area of educational effectiveness should attempt to develop a new theoretical framework. A critical analysis of the current models of educational effectiveness research is provided and reveals that a dynamic model of effectiveness must: (a) be multilevel in nature, (b) be based on

  18. Modelling parasite transmission in a grazing system: the importance of host behaviour and immunity.

    Directory of Open Access Journals (Sweden)

    Naomi J Fox

    Full Text Available Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts' immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites' free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes

  19. Regional input-output models and the treatment of imports in the European System of Accounts

    OpenAIRE

    Kronenberg, Tobias

    2011-01-01

    Input-output models are often used in regional science due to their versatility and their ability to capture many of the distinguishing features of a regional economy. Input-output tables are available for all EU member countries, but they are hard to find at the regional level, since many regional governments lack the resources or the will to produce reliable, survey-based regional input-output tables. Therefore, in many cases researchers adopt nonsurvey techniques to derive regional input-o...

  20. Business model for an International Trade Agent : Importing apparel, footwear and accessories from Colombia

    OpenAIRE

    Peña Archila, Jorge Andres

    2014-01-01

    This thesis proposes a business model for a start-up business that will act as an International Trade agent, the aim of which will be to enhance trade relations between Colombia and Finland due to a free trade agreement between the European Union and Colombia. The scope of this thesis was limited to the products of apparel, footwear and accessories. The primary research was conducted in the form of an unstructured interview with an entrepreneur who has more than two decades of experience ...

  1. Model selection emphasises the importance of non-chromosomal information in genetic studies.

    Directory of Open Access Journals (Sweden)

    Reda Rawi

    Full Text Available Ever since the case of the missing heritability was highlighted some years ago, scientists have been investigating various possible explanations for the issue. However, none of these explanations include non-chromosomal genetic information. Here we describe explicitly how chromosomal and non-chromosomal modifiers collectively influence the heritability of a trait, in this case, the growth rate of yeast. Our results show that the non-chromosomal contribution can be large, adding another dimension to the estimation of heritability. We also discovered, combining the strength of LASSO with model selection, that the interaction of chromosomal and non-chromosomal information is essential in describing phenotypes.

  2. Imported family models? Cohabitation patterns of Latin American women in Spain

    Directory of Open Access Journals (Sweden)

    Clara CORTINA TRILLA

    2010-09-01

    Full Text Available During the last decade, international immigration flows have undergone a dramatic growth in Spain. In this particular context, the purpose of this article is to analyze whether Latin American female migrants residing in Spain largely maintain nuptial and reproductive patterns from their countries of origin. To analyze the prevalence of consensual unions we use three different databases: the Spanish Immigration Survey, the Spanish Labour Force Survey and birth records, all of them corresponding to 2007 and collected by the Spanish Statistical Institute. The study documents the high prevalence of consensual unions among Latin American migrants. Regarding the socio-demographic factors influencing cohabitation, our results show important similarities between Spanish and Latin American women, except for educational attainment.

  3. Report: the current situation of sanitary landfills in Brazil and the importance of the application of economic models.

    Science.gov (United States)

    Neto, Raul Oliveira; Petter, Carlos Otávio; Cortina, José Luis

    2009-12-01

    We present the development stage of the sanitary landfills in Brazil in the context of urban solid residue management, demonstrating the necessity and importance of the employment of economic models. In the article, a cost estimate model is proposed as the basis for studies to be applied by sector management, including the city council, companies, consultants and engineers, contributing to the choice of new areas, public bids, municipal consortia and private public partnerships.

  4. Report: the current situation of sanitary landfills in Brazil and the importance of the application of economic models

    OpenAIRE

    Oliveira Neto, Raúl; Otávio Petter, Carlos; Cortina Pallás, José Luís

    2009-01-01

    We present the development stage of the sanitary landfills in Brazil in the context of urban solid residue management, demonstrating the necessity and importance of the employment of economic models. In the article, a cost estimate model is proposed as the basis for studies to be applied by sector management, including the city council, companies, consultants and engineers, contributing to the choice of new areas, public bids, municipal consortia and private public partnerships. Peer Re...

  5. Mass preserving image registration for lung CT

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin;

    2012-01-01

    on four groups of data: 44 pairs of longitudinal inspiratory chest CT scans with small difference in lung volume; 44 pairs of longitudinal inspiratory chest CT scans with large difference in lung volume; 16 pairs of expiratory and inspiratory CT scans; and 5 pairs of images extracted at end exhale and end...... inhale phases of 4D-CT images. Registration errors, measured as the average distance between vessel tree centerlines in the matched images, are significantly lower for the proposed mass preserving image registration method in the second, third and fourth group, while there is no statistically significant......This paper presents a mass preserving image registration algorithm for lung CT images. To account for the local change in lung tissue intensity during the breathing cycle, a tissue appearance model based on the principle of preservation of total lung mass is proposed. This model is incorporated...

  6. On the importance of paleoclimate modelling for improving predictions of future climate change

    Directory of Open Access Journals (Sweden)

    J. C. Hargreaves

    2009-12-01

    Full Text Available We use an ensemble of runs from the MIROC3.2 AGCM with slab-ocean to explore the extent to which mid-Holocene simulations are relevant to predictions of future climate change. The results are compared with similar analyses for the Last Glacial Maximum (LGM and pre-industrial control climate. We suggest that the paleoclimate epochs can provide some independent validation of the models that is also relevant for future predictions. Considering the paleoclimate epochs, we find that the stronger global forcing and hence larger climate change at the LGM makes this likely to be the more powerful one for estimating the large-scale changes that are anticipated due to anthropogenic forcing. The phenomena in the mid-Holocene simulations which are most strongly correlated with future changes (i.e., the mid to high northern latitude land temperature and monsoon precipitation do, however, coincide with areas where the LGM results are not correlated with future changes, and these are also areas where the paleodata indicate significant climate changes have occurred. Thus, these regions and phenomena for the mid-Holocene may be useful for model improvement and validation.

  7. Flatworm models in pharmacological research: the importance of compound stability testing.

    Science.gov (United States)

    Stalmans, Sofie; Willems, Maxime; Adriaens, Els; Remon, Jean-Paul; D'Hondt, Matthias; De Spiegeleer, Bart

    2014-10-01

    Flatworms possess adult pluripotent stem cells, which make them extraordinary experimental model organisms to assess in vivo the undesirable effects of substances on stem cells. Currently, quality practices, implying evaluation of the stability of the test compound under the proposed experimental conditions, are uncommon in this research field. Nevertheless, performing a stability study during the rational design of in vivo assay protocols will result in more reliable assay results. To illustrate the influence of the stability of the test substance on the final experimental outcome, we performed a short-term International Conference on Harmonization (ICH)-based stability study of cyclophosphamide in the culture medium, to which a marine flatworm model Macrostomum lignano is exposed. Using a validated U(H)PLC method, it was demonstrated that the cyclophosphamide concentration in the culture medium at 20°C is lowered to 80% of the initial concentration after 21days. The multiwell plates, flatworms and diatoms, as well as light exposure, did not influence significantly the cyclophosphamide concentration in the medium. The results of the stability study have practical implications on the experimental set-up of the carcinogenicity assay like the frequency of medium renewal. This case study demonstrates the benefits of applying appropriate quality guidelines already during fundamental research increasing the credibility of the results.

  8. Validating an important aspect of the new ICRP biokinetic model of thorium.

    Science.gov (United States)

    Roth, P; Höllriegl, V; Li, W B; Oeh, U; Schramel, P

    2005-03-01

    The daily urinary excretion of Th (Th) was estimated in 11 adult German subjects who were not exposed occupationally to thorium and its related compounds. Thirty-one urine samples were collected over 24-h periods on different occasions from these subjects and were analyzed using high resolution sector field inductively coupled plasma mass spectrometry (HR-SF-ICP-MS). Using this instrument a limit of detection of 20 pg L for thorium in the reagent blank was achieved. The median (mean) daily urinary thorium excretion was obtained as 1.0 (1.8) ng. This was in good agreement with the mean value of 1.5 ng Th (6 microBq) reported by another group for German population, but is significantly lower in comparison to the daily excretion range of 3.6 to 105 ng reported from other countries. The expected daily urinary excretion of thorium for the adult German population was also calculated by applying the new ICRP biokinetic model of thorium assuming reference intake values. The expected urinary thorium excretion rate for this age group is about 0.1 ng per day. Even if a small contribution from the inhalation is considered, the calculated value will be much lower than the measured values. The reason for the disagreement appears to be the use of a low gastrointestinal absorption factor (f1) of 5 x 10 in the ICRP model. Based on the present study, a higher f1 factor might be proposed separately for dietary incorporated thorium.

  9. Physicochemical properties of copper important for its antibacterial activity and development of a unified model.

    Science.gov (United States)

    Hans, Michael; Mathews, Salima; Mücklich, Frank; Solioz, Marc

    2015-03-16

    Contact killing is a novel term describing the killing of bacteria when they come in contact with metallic copper or copper-containing alloys. In recent years, the mechanism of contact killing has received much attention and many mechanistic details are available. The authors here review some of these mechanistic aspects with a focus on the critical physicochemical properties of copper which make it antibacterial. Known mechanisms of contact killing are set in context to ionic, corrosive, and physical properties of copper. The analysis reveals that the oxidation behavior of copper, paired with the solubility properties of copper oxides, are the key factors which make metallic copper antibacterial. The concept advanced here explains the unique position of copper as an antibacterial metal. Based on our model, novel design criteria for metallic antibacterial materials may be derived.

  10. The importance of magnetic methods for soil mapping and process modelling. Case study in Ukraine

    Science.gov (United States)

    Menshov, Oleksandr; Pereira, Paulo; Kruglov, Oleksandr; Sukhorada, Anatoliy

    2016-04-01

    The correct planning of agriculture areas is fundamental for a sustainable future in Ukraine. After the recent political problems in Ukraine, new challenges emerged regarding sustainability questions. At the same time the soil mapping and modelling are intensively developing all over the world (Pereira et al., 2015; Brevik et al., in press). Magnetic susceptibility (MS) methods are low cost and accurate for the developing maps of agricultural areas, fundamental for Ukrain's economy.This allow to colleact a great amount of soil data, usefull for a better understading of the spatial distribution of soil properties. Recently, this method have been applied in other works in Ukraine and elsewhere (Jordanova et al., 2011; Menshov et al., 2015). The objective of this work is to study the spatial distribution of MS and humus content on the topsoils (0-5 cm) in two different areas. The first is located in Poltava region and the second in Kharkiv region. The results showed that MS depends of soil type, topography and anthropogenic influence. For the interpretation of MS spatial distribution in top soil we consider the frequency and time after the last tillage, tilth depth, fertilizing, and the puddling regarding the vehicle model. On average the soil MS of the top soil of these two cases is about 30-70×10-8 m3/kg. In Poltava region not disturbed soil has on average MS values of 40-50×10-8 m3/kg, for Kharkiv region 50-60×10-8 m3/kg. The tilled soil of Poltava region has on average an MS of 60×10-8 m3/kg, and 70×10-8 m3/kg in Kharkiv region. MS is higher in non-tilled soils than in the tilled ones. The correlation between MS and soil humus content is very high ( up to 0.90) in both cases. Breivik, E., Baumgarten, A., Calzolari, C., Miller, B., Pereira, P., Kabala, C., Jordán, A. Soil mapping, classification, and modelling: history and future directions. Geoderma (in press), doi:10.1016/j.geoderma.2015.05.017 Jordanova D., Jordanova N., Atanasova A., Tsacheva T., Petrov P

  11. Model, First-Principle Calculation of Ammonia Dissociation on Si(100 Surface. Importance of Proton Tunneling

    Directory of Open Access Journals (Sweden)

    Marek Z. Zgierski

    2003-06-01

    Full Text Available Abstract: The dissociation of an ammonia molecule on a cluster of Si atoms simulating the 100 silicon crystal structure with two Si dimers has been investigated by means of the DFT and an approximate instanton methods. The model corresponds to the low coverage limit of the surface. Absolute rate constants of two different dissociation paths are evaluated together with deuterium isotope effects. It is demonstrated that, even at room temperatures, the process is dominated by tunneling and that dissociation to a silicon atom of the adjacent dimer, rather than a silicon within the same dimer, is the prevailing mechanism. This leads to creation of a metastable structure which will slowly decay through a two-step hydrogen atom migration towards the absolute minimum on the potential energy surface corresponding to the NH2 group and the hydrogen atom residing in the same dimer.

  12. Importance of pressure gradient in solid oxide fuel cell electrodes for modeling study

    Science.gov (United States)

    Ni, Meng; Leung, Dennis Y. C.; Leung, Michael K. H.

    The pressure gradients in the electrodes of a solid oxide fuel cell (SOFC) are frequently neglected without any justification in calculating the concentration overpotentials of the SOFC electrodes in modeling studies. In this short communication, a comparative study has been conducted to study the effect of pressure gradients on mass transfer and the resulting concentration overpotentials of an SOFC running on methane (CH 4) fuel. It is found that the pressure gradients in both anode and cathode are significant in the fuel cell electrochemical activities. Neglecting the anode pressure gradient in the calculation can lead to underestimation of the concentration overpotential by about 20% at a typical current density of 5000 A m -2 and at a temperature of 1073 K. The deviation can be even larger at a higher temperature. At the cathode, neglecting the pressure gradient can result in overestimation of the concentration overpotential by about 10% under typical working conditions.

  13. Evaluating the importance of characterizing soil structure and horizons in parameterizing a hydrologic process model

    Science.gov (United States)

    Mirus, Benjamin B.

    2015-01-01

    Incorporating the influence of soil structure and horizons into parameterizations of distributed surface water/groundwater models remains a challenge. Often, only a single soil unit is employed, and soil-hydraulic properties are assigned based on textural classification, without evaluating the potential impact of these simplifications. This study uses a distributed physics-based model to assess the influence of soil horizons and structure on effective parameterization. This paper tests the viability of two established and widely used hydrogeologic methods for simulating runoff and variably saturated flow through layered soils: (1) accounting for vertical heterogeneity by combining hydrostratigraphic units with contrasting hydraulic properties into homogeneous, anisotropic units and (2) use of established pedotransfer functions based on soil texture alone to estimate water retention and conductivity, without accounting for the influence of pedon structures and hysteresis. The viability of this latter method for capturing the seasonal transition from runoff-dominated to evapotranspiration-dominated regimes is also tested here. For cases tested here, event-based simulations using simplified vertical heterogeneity did not capture the state-dependent anisotropy and complex combinations of runoff generation mechanisms resulting from permeability contrasts in layered hillslopes with complex topography. Continuous simulations using pedotransfer functions that do not account for the influence of soil structure and hysteresis generally over-predicted runoff, leading to propagation of substantial water balance errors. Analysis suggests that identifying a dominant hydropedological unit provides the most acceptable simplification of subsurface layering and that modified pedotransfer functions with steeper soil-water retention curves might adequately capture the influence of soil structure and hysteresis on hydrologic response in headwater catchments.

  14. The importance of the unsteady Kutta condition when modelling gust-aerofoil interaction

    Science.gov (United States)

    Ayton, Lorna J.; Gill, J. R.; Peake, N.

    2016-09-01

    The Kutta condition is applied to aerofoils with sharp trailing edges to allow for viscous effects to be considered within a simplified system of equations that are inviscid. This paper discusses in detail the inclusion of an unsteady Kutta condition at a sharp trailing edge during gust-aerofoil interaction and illustrates how the analytic solution for the far-field noise generated by this interaction changes if the unsteady Kutta condition is neglected, or more precisely, if the unsteady pressure is permitted to be singular at the trailing edge. The analytic solution, both with and without the unsteady Kutta condition, is compared with numerical results that have no imposed unsteady Kutta condition. Importantly the results agree well only when the unsteady Kutta condition is neglected in the analytic solution. This paper highlights where the far-field acoustics are most affected by neglecting the unsteady Kutta condition for a variety of singularities that can occur in the unsteady pressure at the trailing edge and shows that results permitting different behaviour in the unsteady surface pressure at the trailing edge could give significantly different far-field noise predictions, even though the surface pressure elsewhere along the aerofoil surface agrees with benchmark solutions.

  15. Saliva Preservative for Diagnostic Purposes

    Science.gov (United States)

    Pierson, Duane L.; Mehta, Satish K.

    2012-01-01

    Saliva is an important body fluid for diagnostic purposes. Glycoproteins, glucose, steroids, DNA, and other molecules of diagnostic value are found in saliva. It is easier to collect as compared to blood or urine. Unfortunately, saliva also contains large numbers of bacteria that can release enzymes, which can degrade proteins and nucleic acids. These degradative enzymes destroy or reduce saliva s diagnostic value. This innovation describes the formulation of a chemical preservative that prevents microbial growth and inactivates the degradative enzymes. This extends the time that saliva can be stored or transported without losing its diagnostic value. Multiple samples of saliva can be collected if needed without causing discomfort to the subject and it does not require any special facilities to handle after it is collected.

  16. 40 CFR 1068.360 - What restrictions apply to assigning a model year to imported engines and equipment?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What restrictions apply to assigning a model year to imported engines and equipment? 1068.360 Section 1068.360 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS GENERAL COMPLIANCE PROVISIONS FOR...

  17. The importance of dietary control in the development of a peanut allergy model in Brown Norway rats

    NARCIS (Netherlands)

    Jonge, J.D. de; Knippels, L.M.J.; Ezendam, J.; Odink, J.; Penninks, A.H.; Loveren, H. van

    2007-01-01

    This report describes the further development of a peanut allergy model in Brown Norway (BN) rats and in particular the importance of allergen-free breeding of the laboratory animals for the allergen to be used. For this purpose BN rats were bred for 3 generations on soy- and peanut-free feed since

  18. Predicting important residues and interaction pathways in proteins using Gaussian Network Model: binding and stability of HLA proteins.

    Directory of Open Access Journals (Sweden)

    Turkan Haliloglu

    Full Text Available A statistical thermodynamics approach is proposed to determine structurally and functionally important residues in native proteins that are involved in energy exchange with a ligand and other residues along an interaction pathway. The structure-function relationships, ligand binding and allosteric activities of ten structures of HLA Class I proteins of the immune system are studied by the Gaussian Network Model. Five of these models are associated with inflammatory rheumatic disease and the remaining five are properly functioning. In the Gaussian Network Model, the protein structures are modeled as an elastic network where the inter-residue interactions are harmonic. Important residues and the interaction pathways in the proteins are identified by focusing on the largest eigenvalue of the residue interaction matrix. Predicted important residues match those known from previous experimental and clinical work. Graph perturbation is used to determine the response of the important residues along the interaction pathway. Differences in response patterns of the two sets of proteins are identified and their relations to disease are discussed.

  19. The importance of becoming double-stranded: Innate immunity and the kinetic model of HIV-1 central plus strand synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Poeschla, Eric, E-mail: poeschla.eric@mayo.edu

    2013-06-20

    Central initiation of plus strand synthesis is a conserved feature of lentiviruses and certain other retroelements. This complication of the standard reverse transcription mechanism produces a transient “central DNA flap” in the viral cDNA, which has been proposed to mediate its subsequent nuclear import. This model has assumed that the important feature is the flapped DNA structure itself rather than the process that produces it. Recently, an alternative kinetic model was proposed. It posits that central plus strand synthesis functions to accelerate conversion to the double-stranded state, thereby helping HIV-1 to evade single-strand DNA-targeting antiviral restrictions such as APOBEC3 proteins, and perhaps to avoid innate immune sensor mechanisms. The model is consistent with evidence that lentiviruses must often synthesize their cDNAs when dNTP concentrations are limiting and with data linking reverse transcription and uncoating. There may be additional kinetic advantages for the artificial genomes of lentiviral gene therapy vectors. - Highlights: • Two main functional models for HIV central plus strand synthesis have been proposed. • In one, a transient central DNA flap in the viral cDNA mediates HIV-1 nuclear import. • In the other, multiple kinetic consequences are emphasized. • One is defense against APOBEC3G, which deaminates single-stranded DNA. • Future questions pertain to antiviral restriction, uncoating and nuclear import.

  20. Modelo Educativo basado en competencias: Importancia y necesidad / Educational model based in competenciy: importance and necessity

    Directory of Open Access Journals (Sweden)

    José Ángel García Retana

    2011-12-01

    Full Text Available ResumenCon el surgimiento de las tecnologías de la información y la comunicación, la Humanidad ha logrado desarrollar un nivel de conocimientos sin precedente en la historia, constituyéndose éste en el principal recurso con cuenta para enfrentar la degradación de los recursos naturales del planeta. Para lograr que el conocimiento ocupe el papel indicado se requiere la construcción de un nuevo modelo educativo que centre el currículo en el educando, particularmente en el desarrollo de sus competencias, de manera tal que se logre una convergencia entre lo individual y lo social en aspectos ligados a lo cognoscitivo, afectivo y psicológico, que potencien una capacidad adaptativa al entorno generado en los últimos años. Solo así se podrá estimular la creatividad y la innovación para enfrentar los retos planteados por dicho entorno, desde una perspectiva holística y transdiciplinar capaz de superar los modelos educativos heredados del siglo XX centrados en la adquisición de información. En este nuevo marco contextual el papel del docente se debe redefinir, pasando de ser un transmisor de conocimientos a un gestionador de ambientes de aprendizaje.AbstractWith the emergence of information technology and communication, Humanity has deveoped an unprecedented level of knowledge in history, becoming the main resource it has to face the degradation of the planet´s natural resources. To achieve that knowledge occupies the indicated role, is required to build a new educational model to center the curriculum on the learner, particulary in the development of their competences, so as to achieve a convergence between individual an social aspects related to the cognitive, emotional and psychological, that enhance adaptive capacity to enviroment generated in recent years. Only then can stimulate creativity and innovation to meet the challenges posed by such an environment, a holistic and transdiciplinary able to overcome the educational model